U.S. patent application number 16/928471 was filed with the patent office on 2022-01-20 for downlink packet replication to support handover.
The applicant listed for this patent is Cisco Technology, Inc.. Invention is credited to Oliver James Bull, Mark Grayson, Srinath Gundavelli, Sangram Kishore Lakkaraju, Louis Gwyn Samuel.
Application Number | 20220022124 16/928471 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-20 |
United States Patent
Application |
20220022124 |
Kind Code |
A1 |
Gundavelli; Srinath ; et
al. |
January 20, 2022 |
DOWNLINK PACKET REPLICATION TO SUPPORT HANDOVER
Abstract
Techniques are provided for downlink packet replication to
support handovers. In one example, downlink packet replication
occurs on a fabric node in an S1AP handover scenario. In another
example, downlink packet replication occurs on a source Access
Point (AP) using a target AP as a secondary AP in an S1AP handover
scenario. In yet another example, downlink packet replication
occurs on a source AP using packet encapsulation in an S1AP
handover scenario. In still another example, downlink packet
replication occurs on a source AP in an X2 handover scenario.
Similar techniques are provided for any suitable
telecommunications/cellular technology.
Inventors: |
Gundavelli; Srinath; (San
Jose, CA) ; Lakkaraju; Sangram Kishore; (Bangalore,
IN) ; Grayson; Mark; (Berkshire, GB) ; Bull;
Oliver James; (Bristol, GB) ; Samuel; Louis Gwyn;
(Wiltshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cisco Technology, Inc. |
San Jose |
CA |
US |
|
|
Appl. No.: |
16/928471 |
Filed: |
July 14, 2020 |
International
Class: |
H04W 40/36 20060101
H04W040/36; H04W 36/08 20060101 H04W036/08; H04W 68/00 20060101
H04W068/00; H04W 60/00 20060101 H04W060/00; H04W 76/12 20060101
H04W076/12; H04W 76/11 20060101 H04W076/11; H04W 72/12 20060101
H04W072/12 |
Claims
1. A method comprising: obtaining a notification that a handover is
to occur for a user equipment from a source access point to a
target access point; identifying a routing locator for a tunnel
router associated with the source access point and a routing
locator for a tunnel router associated with the target access
point; and providing, to a map server, a registration message
including a mapping of an endpoint identifier of the user equipment
to the routing locator for the tunnel router associated with the
source access point and the routing locator for the tunnel router
associated with the target access point, wherein based on the
registration message, the map server causes downlink packets
destined for the user equipment to be replicated and provided to
the source access point and to the target access point.
2. The method of claim 1, wherein the tunnel router associated with
the source access point and the tunnel router associated with the
target access point are a single tunnel router, and wherein:
identifying includes identifying a single routing locator for the
single tunnel router; and providing includes providing a
registration message including a mapping of the endpoint identifier
of the user equipment to the single routing locator.
3. The method of claim 2, wherein: providing includes providing a
registration message including an indication for the single tunnel
router to replicate the downlink packets destined for the user
equipment to generate a first copy of the downlink packets destined
for the user equipment and a second copy of the downlink packets
destined for the user equipment, provide the first copy of the
downlink packets destined for the user equipment to the source
access point, and provide the second copy of the downlink packets
destined for the user equipment to the target access point; based
on the registration message, the map server provides, to the single
tunnel router, a notification message including the mapping of the
endpoint identifier of the user equipment to the single routing
locator and the indication; and based on the notification message,
the single tunnel router replicates the downlink packets destined
for the user equipment to generate the first copy of the downlink
packets destined for the user equipment and the second copy of the
downlink packets destined for the user equipment, provides the
first copy of the downlink packets destined for the user equipment
to the source access point, and provides the second copy of the
downlink packets destined for the user equipment to the target
access point.
4. The method of claim 2, wherein: providing includes providing a
registration message including an indication that the target access
point is a secondary access point to which the single tunnel router
is to provide any of the downlink packets destined for the user
equipment that are obtained from the source access point; based on
the registration message, the map server provides, to the single
tunnel router, a notification message including the mapping of the
endpoint identifier of the user equipment to the single routing
locator and the indication that the target access point is the
secondary access point; the single tunnel router provides the
downlink packets destined for the user equipment to the source
access point; the source access point replicates the downlink
packets destined for the user equipment to generate a first copy of
the downlink packets destined for the user equipment and a second
copy of the downlink packets destined for the user equipment, and
provides the first copy of the downlink packets destined for the
user equipment to the single tunnel router; and based on the
notification message, the single tunnel router provides the first
copy of the downlink packets destined for the user equipment to the
target access point.
5. The method of claim 2, further comprising: obtaining a
notification that the handover has occurred; and providing, to the
map server, another registration message including the mapping of
the endpoint identifier of the user equipment to the single routing
locator, the other registration message including an indication
that the single routing locator is associated with the target
access point, wherein based on the other registration message, the
map server provides, to the single tunnel router, a notification
message including the mapping of the endpoint identifier of the
user equipment to the single routing locator and an indication to
provide the downlink packets destined for the user equipment to the
target access point, and based on the notification message, the
single tunnel router provides the downlink packets destined for the
user equipment to the target access point.
6. The method of claim 1, wherein the tunnel router associated with
the source access point is different from the tunnel router
associated with the target access point.
7. The method of claim 6, wherein: providing includes providing a
registration message including an indication for a border node to
replicate the downlink packets destined for the user equipment to
generate a first copy of the downlink packets destined for the user
equipment and a second copy of the downlink packets destined for
the user equipment, provide the first copy of the downlink packets
destined for the user equipment to the tunnel router associated
with the source access point, and provide the second copy of the
downlink packets destined for the user equipment to the tunnel
router associated with the target access point; based on the
registration message, the map server provides, to the border node,
a publication including the mapping of the endpoint identifier of
the user equipment to the routing locator for the tunnel router
associated with the source access point and the routing locator for
the tunnel router associated with the target access point, and the
indication for the border node to replicate the downlink packets
destined for the user equipment to generate the first copy of the
downlink packets destined for the user equipment and the second
copy of the downlink packets destined for the user equipment,
provide the first copy of the downlink packets destined for the
user equipment to the tunnel router associated with the source
access point, and provide the second copy of the downlink packets
destined for the user equipment to the tunnel router associated
with the target access point; and based on the publication, the
border node replicates the downlink packets destined for the user
equipment to generate the first copy of the downlink packets
destined for the user equipment and the second copy of the downlink
packets destined for the user equipment, provides the first copy of
the downlink packets destined for the user equipment to the tunnel
router associated with the source access point, and provides the
second copy of the downlink packets destined for the user equipment
to the tunnel router associated with the target access point.
8. The method of claim 7, further comprising: obtaining a
notification that the handover has occurred; and providing, to the
map server, another registration message including the mapping of
the endpoint identifier of the user equipment to the routing
locator for the tunnel router associated with the target access
point, wherein based on the other registration message, the map
server provides, to the border node, a publication including the
mapping of the endpoint identifier of the user equipment to the
routing locator for the tunnel router associated with the target
access point, and an indication to provide the downlink packets
destined for the user equipment to the tunnel router associated
with the target access point, and based on the publication, the
border node provides the downlink packets destined for the user
equipment to the tunnel router associated with the target access
point.
9. The method of claim 6, wherein: providing includes providing a
registration message including an indication that the target access
point is a secondary access point to which the tunnel router
associated with the source access point is to provide any of the
downlink packets destined for the user equipment that are obtained
from the source access point; based on the registration message,
the map server provides, to the tunnel router associated with the
source access point, a notification message including the mapping
of the endpoint identifier of the user equipment to the routing
locator for the tunnel router associated with the source access
point and the routing locator for the tunnel router associated with
the target access point, and the indication that the target access
point is the secondary access point; the tunnel router associated
with the source access point provides the downlink packets destined
for the user equipment to the source access point; the source
access point replicates the downlink packets destined for the user
equipment to generate a first copy of the downlink packets destined
for the user equipment and a second copy of the downlink packets
destined for the user equipment and provides the first copy of the
downlink packets destined for the user equipment to the tunnel
router associated with the source access point; based on the
notification message, the tunnel router associated with the source
access point provides the first copy of the downlink packets
destined for the user equipment to the tunnel router associated
with the target access point; and the tunnel router associated with
the target access point provides the first copy of the downlink
packets destined for the user equipment to the target access
point.
10. The method of claim 9, further comprising: obtaining a
notification that the handover has occurred; and providing, to the
map server, another registration message including the mapping of
the endpoint identifier of the user equipment to the routing
locator for the tunnel router associated with the target access
point, wherein based on the other registration message, the map
server provides, to the tunnel router associated with the target
access point, a notification message including the mapping of the
endpoint identifier of the user equipment to the routing locator
for the tunnel router associated with the target access point, and
an indication to provide the downlink packets destined for the user
equipment to the target access point, and based on the notification
message, the tunnel router associated with the target access point
provides the downlink packets destined for the user equipment to
the target access point.
11. The method of claim 1, wherein: the source access point is a
first fourth generation evolved Node B and the target access point
is a second fourth generation evolved Node B; the source access
point is a first fifth generation next generation Node B and the
target access point is a second fifth generation next generation
Node B; or the source access point is a first citizens broadband
radio service device and the target access point is a second
citizens broadband radio service device.
12. A method comprising: obtaining a notification that a handover
is to occur for a user equipment from a source access point to a
target access point; providing, to the target access point, an
indication to decapsulate encapsulated downlink packets destined
for the user equipment, wherein the encapsulated downlink packets
destined for the user equipment are encapsulated with an outer
header identifying the source access point as a source of the
encapsulated downlink packets destined for the user equipment and
further identifying the target access point as a destination of the
encapsulated downlink packets destined for the user equipment; and
providing, to the source access point, an indication to replicate
downlink packets destined for the user equipment to generate a
first copy of the downlink packets destined for the user equipment
and a second copy of the downlink packets destined for the user
equipment, and encapsulate the first copy of the downlink packets
destined for the user equipment with the outer header to generate
the encapsulated downlink packets destined for the user
equipment.
13. The method of claim 12, wherein the source access point and the
target access point are associated with a single tunnel router.
14. The method of claim 13, wherein: the source access point
replicates the downlink packets destined for the user equipment to
generate the first copy of the downlink packets destined for the
user equipment and the second copy of the downlink packets destined
for the user equipment, encapsulates the first copy of the downlink
packets destined for the user equipment with the outer header to
generate the encapsulated downlink packets destined for the user
equipment, and provides the encapsulated downlink packets destined
for the user equipment to the single tunnel router; the single
tunnel router identifies the target access point as the destination
of the encapsulated downlink packets destined for the user
equipment based on the outer header and provides the encapsulated
downlink packets destined for the user equipment to the target
access point; and the target access point decapsulates the
encapsulated downlink packets destined for the user equipment.
15. The method of claim 13, further comprising: obtaining a
notification that the handover has occurred; and providing, to a
map server, a registration message including a mapping of an
endpoint identifier of the user equipment to a single routing
locator for the single tunnel router, the registration message
including an indication that the single routing locator is
associated with the target access point, wherein based on the
registration message, the map server provides, to the single tunnel
router, a notification message including the mapping of the user
equipment to the single routing locator and an indication to
provide the downlink packets destined for the user equipment to the
target access point, and based on the notification message, the
single tunnel router provide the downlink packets destined for the
user equipment to the target access point.
16. The method of claim 12, wherein a tunnel router associated with
the source access point is different from a tunnel router
associated with the target access point.
17. The method of claim 16, wherein: the source access point
replicates the downlink packets destined for the user equipment to
generate the first copy of the downlink packets destined for the
user equipment and the second copy of the downlink packets destined
for the user equipment, encapsulates the first copy of the downlink
packets destined for the user equipment with the outer header to
generate the encapsulated downlink packets destined for the user
equipment, and provides the encapsulated downlink packets destined
for the user equipment to the tunnel router associated with the
source access point; the tunnel router associated with the source
access point identifies the target access point as the destination
of the encapsulated downlink packets destined for the user
equipment based on the outer header and provides the encapsulated
downlink packets destined for the user equipment to the tunnel
router associated with the target access point; the tunnel router
associated with the target access point identifies the target
access point as the destination of the encapsulated downlink
packets destined for the user equipment based on the outer header
and provides the encapsulated downlink packets destined for the
user equipment to the target access point; and the target access
point decapsulates the encapsulated downlink packets destined for
the user equipment.
18. The method of claim 16, further comprising: obtaining a
notification that the handover has occurred; and providing, to a
map server, a registration message including a mapping of an
endpoint identifier of the user equipment to the tunnel router
associated with the target access point, wherein based on the
registration message, the map server provides, to the tunnel router
associated with the target access point, a notification message
including the mapping of the user equipment to the tunnel router
associated with the target access point and an indication to
provide the downlink packets destined for the user equipment to the
target access point; and based on the notification message, the
tunnel router associated with the target access point provides the
downlink packets destined for the user equipment to the target
access point.
19. The method of claim 12, further comprising: obtaining a
notification that the target access point has stopped or will stop
decapsulating the encapsulated downlink packets destined for the
user equipment; and providing, to the source access point, an
indication to stop replicating the downlink packets destined for
the user equipment and encapsulating the downlink packets destined
for the user equipment with the outer header to generate the
encapsulated downlink packets destined for the user equipment.
20. The method of claim 12, wherein: the source access point is a
first fourth generation evolved Node B and the target access point
is a second fourth generation evolved Node B; the source access
point is a first fifth generation next generation Node B and the
target access point is a second fifth generation next generation
Node B; or the source access point is a first citizens broadband
radio service device and the target access point is a second
citizens broadband radio service device.
21. An apparatus comprising: a network interface configured to
obtain or provide network communications; and one or more
processors coupled to the network interface, wherein the one or
more processors are configured to: obtain a notification that a
handover is to occur for a user equipment from a source access
point to a target access point; identify a routing locator for a
tunnel router associated with the source access point and a routing
locator for a tunnel router associated with the target access
point; and provide, to a map server, a registration message
including a mapping of an endpoint identifier of the user equipment
to the routing locator for the tunnel router associated with the
source access point and the routing locator for the tunnel router
associated with the target access point, wherein based on the
registration message, the map server causes downlink packets
destined for the user equipment to be replicated and provided to
the source access point and to the target access point.
22. The apparatus of claim 21, wherein the tunnel router associated
with the source access point and the tunnel router associated with
the target access point are a single tunnel router, and wherein the
one or more processors are configured to: identify a single routing
locator for the single tunnel router; and provide a registration
message including a mapping of the endpoint identifier of the user
equipment to the single routing locator.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to telecommunications
technology.
BACKGROUND
[0002] Handover support for a User Equipment (UE) in a 3rd
Generation Partnership Project (3GPP) network can be based on S1AP
or X2 handover procedures in the fourth generation (4G) case. X2
handover procedures may be utilized when an X2 interface is
available between the Access Points (APs) involved in the handover.
S1AP handover procedures may be utilized when no such X2 interface
is available. These handover procedures may ensure that the
connection to the UE is maintained as the UE moves between two
APs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 illustrates a system configured for downlink packet
replication to support a handover, according to an example
embodiment.
[0004] FIG. 2 illustrates a flowchart of a method for downlink
packet replication to support an S1AP handover.
[0005] FIG. 3 illustrates a call flow diagram of a method of
preparing for replication of downlink packets on a fabric node in
an S1AP handover scenario in which a source Access Point (AP) and a
target AP are associated with a single tunnel router, according to
an example embodiment.
[0006] FIG. 4 illustrates a call flow diagram of a method for
replicating downlink packets on a fabric node in an S1AP handover
scenario in which a source AP and a target AP are associated with a
single tunnel router, according to an example embodiment.
[0007] FIG. 5 illustrates a call flow diagram of a method of
preparing for replication of downlink packets on a fabric node in
an S1AP handover scenario in which a source AP and a target AP are
associated with respective tunnel routers, according to an example
embodiment.
[0008] FIG. 6 illustrates a call flow diagram of a method for
replicating downlink packets on a fabric node in an S1AP handover
scenario in which a source AP and a target AP are associated with
respective tunnel routers, according to an example embodiment.
[0009] FIG. 7 illustrates a call flow diagram of a method of
preparing for replication of downlink packets on a source AP using
a target AP as a secondary AP in an S1AP handover scenario in which
the source AP and the target AP are associated with a single tunnel
router, according to an example embodiment.
[0010] FIG. 8 illustrates a call flow diagram of a method for
replicating downlink packets on a source AP using a target AP as a
secondary AP in an S1AP handover scenario in which the source AP
and a target AP are associated with a single tunnel router,
according to an example embodiment.
[0011] FIG. 9 illustrates a call flow diagram of a method of
preparing for replication of downlink packets on a source AP using
a target AP as a secondary AP in an S1AP handover scenario in which
the source AP and a target AP are associated with respective tunnel
routers, according to an example embodiment.
[0012] FIG. 10 illustrates a call flow diagram of a method for
replicating downlink packets on a source AP using a target AP as a
secondary AP in an S1AP handover scenario in which the source AP
and a target AP are associated with respective tunnel routers,
according to an example embodiment.
[0013] FIG. 11 illustrates a call flow diagram of a method of
preparing for replication of downlink packets on a source AP using
packet encapsulation in an S1AP handover scenario in which the
source AP and a target AP are associated with a single tunnel
router, according to an example embodiment.
[0014] FIG. 12 illustrates a call flow diagram of a method for
replicating downlink packets on a source AP using packet
encapsulation in an S1AP handover scenario in which the source AP
and a target AP are associated with a single tunnel router,
according to an example embodiment.
[0015] FIG. 13 illustrates a call flow diagram of a method of
preparing for replication of downlink packets on a source AP using
packet encapsulation in an S1AP handover scenario in which the
source AP and a target AP are associated with respective tunnel
routers, according to an example embodiment.
[0016] FIG. 14 illustrates a call flow diagram of a method for
replicating downlink packets on a source AP using packet
encapsulation in an S1AP handover scenario in which the source AP
and a target AP are associated with respective tunnel routers,
according to an example embodiment.
[0017] FIGS. 15A and 15B collectively illustrate a call flow
diagram of a method for replicating downlink packets on a source AP
in an X2 handover scenario in which the source AP and a target AP
are associated with a single tunnel router, according to an example
embodiment.
[0018] FIGS. 16A and 16B illustrates a call flow diagram of a
method for replicating downlink packets on a source access point in
an X2 handover scenario in which the source AP and a target AP are
associated with respective tunnel routers, according to an example
embodiment.
[0019] FIG. 17 illustrates a block diagram of a computing device
configured for downlink packet replication to support a handover,
according to an example embodiment.
[0020] FIG. 18 illustrates a flowchart of a method for downlink
packet replication on a fabric node or on a source AP using a
target AP as a secondary AP in an S1AP handover scenario, according
to an example embodiment.
[0021] FIG. 19 illustrates a flowchart of a method for downlink
packet replication on a source AP using packet encapsulation in an
S1AP handover scenario, according to an example embodiment.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0022] Overview
[0023] In one example embodiment, techniques are provided for
downlink packet replication on a fabric node or on a source Access
Point (AP) using a target AP as a secondary AP in an S1AP handover
scenario. A notification that a handover is to occur for a User
Equipment (UE) from a source AP to a target AP is obtained. A
Routing Locator (RLOC) for a tunnel router associated with the
source AP and a RLOC for a tunnel router associated with the target
AP are obtained. A registration message including a mapping of an
endpoint identifier of the UE to the RLOC for the tunnel router
associated with the source AP and the RLOC for the tunnel router
associated with the target AP is provided to a Map Server (MS).
Based on the registration message, the MS causes downlink packets
destined for the UE to be replicated and provided to the source AP
and to the target AP.
[0024] In another example embodiment, techniques are provided for
downlink packet replication on a source AP using packet
encapsulation in an S1AP handover scenario. a notification that a
handover is to occur for a UE from a source AP to a target AP is
obtained. An indication to decapsulate encapsulated downlink
packets destined for the UE is provided to the target AP. The
encapsulated downlink packets destined for the UE are encapsulated
with an outer header identifying the source AP as a source of the
encapsulated downlink packets destined for the UE and further
identifying the target AP as a destination of the encapsulated
downlink packets destined for the UE. An indication to replicate
downlink packets destined for the UE to generate a first copy of
the downlink packets destined for the UE and a second copy of the
downlink packets destined for the UE, and encapsulate the first
copy of the downlink packets destined for the UE with the outer
header to generate the encapsulated downlink packets destined for
the UE, is provided to the source AP.
Example Embodiments
[0025] FIG. 1 illustrates an example system 100 configured for
downlink packet replication to support a handover (e.g., an S1AP or
X2 handover). System 100 includes User Interface (UE) 105, tracking
area 110, network fabric 115, and Data Network (DN) 120. Tracking
area 110 includes Access Points (APs) 125(1)-125(3), which provide
network access coverage to respective coverage areas 130(1)-130(3).
Network fabric 115 includes control plane entities such as Cellular
Termination Function (CTF) 135, Map Server (MS) 140,
Authentication, Authorization, and Accounting (AAA) server 145, and
Home Subscriber Server (HSS) 150, and user/data plane entities such
as switches 155(1) and 155(2), network nodes (e.g., routers)
160(1)-160(4), and border node 165.
[0026] UE 105 may be associated with any suitable device configured
to initiate a flow in system 100. For example, UE 105 may include a
computer, a vehicle and/or any other transportation-related device
having electronic devices configured thereon, an automation device,
an enterprise device, an appliance, an Internet of Things (IoT)
device, a Personal Digital Assistant (PDA), a laptop or electronic
notebook, a cellular telephone, a smartphone, a tablet, an Internet
Protocol (IP) phone, and/or any other device and/or combination of
devices, components, elements, and/or objects capable of initiating
voice, audio, video, media, or data exchanges within system 100. UE
105 may also include any suitable interface to a human user such as
a microphone, a display, a keyboard, or other terminal equipment.
UE 105 may also be any device that seeks to initiate a
communication on behalf of another entity or element such as a
program, a database, or any other component, device, element, or
object capable of initiating an exchange within system 100. UE 105
may be configured with appropriate hardware (e.g., processor(s),
memory element(s), antennas and/or antenna arrays, baseband
processors (modems), and/or the like), software, logic, and/or the
like to facilitate respective over-the-air (air) interfaces for
accessing/connecting to APs 125(1)-125(3). It will be appreciated
that any number of UEs may be present in system 100.
[0027] Network fabric 115 may be associated with a private network,
such as a software-defined access fabric configured specifically
for use by users associated with an enterprise. By `private` it is
meant that a private cellular access network provides network
connectivity/services to clients (e.g., UE 105) served by a network
operator and/or service provider of the private cellular access
network, such as an enterprise. In some instances, a private
network may also be referred to as a non-public network (NPN). In
one example, a private cellular access network may be considered to
be a network that may be implemented to serve enterprise purposes
(e.g., business purposes, government purposes, educational
purposes, etc.) for enterprise clients (e.g., enterprise
users/devices/etc.) in which the private cellular access network
may be operated by any combination of traditional mobile network
operators/service providers, enterprise network operators/service
providers, and/or third party network operators/service providers
(e.g., neutral host network operators/service providers, cloud
service providers, etc.). In one example, the user of UE 105 is an
employee of the enterprise associated with network fabric 115.
[0028] In various embodiments, DN 120 may be any combination of the
Internet, an Internet Protocol (IP) Multimedia Subsystem (IMS),
Ethernet network, Ethernet switching system(s), and/or the like. DN
120 may facilitate user plane (e.g., user data/data transfer)
connectivity for per-access UE 105 sessions. For example, UE 105
may access various services, applications, etc. from DN 120.
[0029] One or more of APs 125(1)-125(3) may be cellular APs that
terminate a cellular (e.g., fourth generation (4G) Long-Term
Evolution (LTE) or fifth generation (5G) New Radio (NR)) air
interface and may be configured with appropriate hardware (e.g.,
processor(s), memory element(s), antennas and/or antenna arrays,
baseband processors (modems), and/or the like), software, logic,
and/or the like to provide over-the-air coverage for a private
cellular access network (e.g., private 4G LTE, private 5G NR,
private Citizens Broadband Radio Service (CBRS), etc.). In various
embodiments, APs 125(1)-125(3) may be implemented as any
combination of an evolved Node B (eNB) to facilitate 4G LTE air
accesses, a next generation Node B (gNB) to facilitate 5G NR air
accesses, a next generation (NG) radio to facilitate any next
generation air accesses, a CBRS Device (CBSD) to facilitate CBRS
accesses, and/or the like now known or hereafter developed.
[0030] CTF 135 may be a control plane entity that provides or is
responsible for any combination of cellular-based access
authentication services, authorization services, mobility
management control, session management services with various
functions being supported on a per-session basis, selection and
control of user plane entities (e.g., per-session), if applicable,
and/or the like. In various embodiments, CTF 135 may be implemented
with functionality as may be inherited from any combination of a 4G
LTE Mobility Management Entity (MME); a Serving Gateway (SGW),
and/or a Packet Data Network (PDN) Gateway (PGW); a 5G Access and
Mobility Management Function (AMF) and/or Session Management
Function (SMF); and/or the like now known or hereafter developed.
In one example, CTF 135 may terminate the S1-MME interface (in the
4G case) or the N1 interface (in the 5G case) from one or more of
APs 125(1)-125(3) (e.g., one or more eNBs/gNBs). The 4G case with
the S1-MME interfaces is illustrated in FIG. 1.
[0031] MS 140 is a control plane entity (e.g., a Locator Identifier
(ID) Separation Protocol (LISP) function) that represents a
distributed mapping database and service that accepts registration
information for clients and/or other endpoint users/devices, etc.
(e.g., UE 105), and stores mappings between numbering or name space
constructs. LISP is a control plane protocol that may facilitate IP
mobility for system 100. Although embodiments herein provide
example details associated with a LISP implementation, other
control plane protocols may be implemented for system 100
including, but not limited to, Proxy Mobile IP version 6 (PMIPv6),
Identifier Locator Addressing (ILA), etc.
[0032] A LISP implementation may utilize various constructs
including Routing Locators (RLOCs) that may be associated with edge
and border switches (e.g., switches 155(1) and 155(2) and border
node 165)) and Endpoint IDs (EIDs) that may be associated
with/identify clients or other endpoints (e.g., UE 105) in order to
facilitate mobility for network fabric 115. An RLOC may be an IP
address or other ID associated with an element in which the
nomenclature `RLOC=element` may generally represent an RLOC set to
the ID of the element. IP addresses as discussed for embodiments
described herein may be implemented as IP version 4 (IPv4) and/or
IPv6 addresses. Other variations for setting an RLOC may be
envisioned using, for example, Type-Length-Value (TLV) expressions,
or the like.
[0033] For the LISP implementation of system 100, MS 140 may store
mappings, generally known as EID-to-RLOC mappings, between RLOCs
for fabric switches/functions/etc. (e.g., switches 155(1) and
155(2) and border node 165) and EIDs for clients (e.g., UE 105) for
which traffic is handled or otherwise associated with the
switches/functions/etc. MS 140 may associate EIDs with any
combination of IP addresses, Media Access Control (MAC) addresses,
or other identifiers for UEs for different EID-to-RLOC mappings
that may be maintained/managed within network fabric 115. MS 140
may also communicate EID-to-RLOC mapping information to various
elements of network fabric (e.g., switches 155(1) and 155(2),
network nodes 160(1)-160(4), border node 165, etc.). MS 140 may
include map resolver functionality such as obtaining map request
messages and processing/forwarding those messages for MS 140. Such
information may be stored in the map-cache of the elements to
facilitate routing via network fabric 115.
[0034] AAA server 145 and HSS 150 may provide/be responsible for
any combination of: providing authentication, authorization, and
accounting functions for clients (e.g., UE 105) that may be present
in system 100; managing subscription/policy information for one or
more clients that may be present in system 100 (e.g., access
profile information, among other subscription/policy information);
maintaining per-client session information for various accesses to
which each client is connected; combinations thereof, and/or the
like. In various embodiments, AAA server 145 and HSS 150 may be
implemented as any combination of standalone and/or combined
elements (e.g., separate AAA and HSS elements or a combined AAA/HSS
element) in order to facilitate AAA-based operations as well as
policy-based operations for network fabric 115.
[0035] Generally, authentication refers to the process where an
entity's identity is authenticated, typically by providing evidence
that it holds a specific digital identity such as an
identifier/identity and corresponding credentials/authentication
attributes/etc. Generally, authorization can be used to determine
whether a particular entity is authorized to perform a given
activity, typically inherited from authentication when logging on
to an application or service. In various instances, authorization
may be determined based on a range of restrictions, for example
time-of-day restrictions, or physical location restrictions, or
restrictions against multiple accesses by the same entity or
user/device. Generally, accounting refers to the tracking of
network resource consumption by users/devices for the purpose of
capacity and trend analysis, cost allocation, billing, etc. It will
be appreciated that AAA server 145 and/or HSS 150 may include
cellular authentication functionality distributed across one or
more servers.
[0036] In various embodiments, AAA server 145 and/or HSS 150 may be
configured with or obtain (e.g., from an external
database/service/etc.) per-client access profile information that
may include, but not be limited to, client (e.g., user/device)
identity information, authentication type attributes (e.g.,
authentication type, sub-type, etc.), authentication attributes
(e.g., credentials, passwords, keys, etc.), combinations thereof,
and/or the like. Additionally, AAA server 145 and/or HSS 150 may be
configured with or obtain (e.g., from an external
database/service/etc.) per-client subscription/policy information
that may include, but not be limited to, service quality
information such as Quality of Service (QoS) information, QoS Class
Identifier (QCI), Guaranteed Bit Rate (GBR), Maximum Bit Rate
(MBR), Aggregate Maximum Bit Rate (AMBR), Allocation and Retention
Priority (ARP), packet delay information, packet loss information,
combinations thereof, and/or the like for one or more client
sessions. In various embodiments, subscription/policy information
may also include a 3rd Generation Partnership Project (3GPP)
service name such as AP Name (APN) information (for 4G networks),
Data Network Name (DNN) information (for 5G networks), combinations
thereof, and/or the like for one or more client sessions.
[0037] In various embodiments, AAA server 145 and/or HSS 150 may be
configured with one or more databases/repositories/etc. and/or may
interface with one or more external databases/repositories/etc. in
order to obtain and/or be configured with access profile
information, subscription/policy information, etc. for clients.
Such internal/external databases/repositories/etc. may include any
combination of enterprise databases, repositories, and/or the like
for one or more clients that may be allowed to connect to accesses
with which network fabric 115 may interface. In various
embodiments, AAA server 145 and/or HSS 150 may be implemented as an
AAA server, an enterprise policy server/manager, a 3GPP HSS,
combinations thereof, and/or the like.
[0038] AAA server 145 may be capable of interfacing/communicating
with other elements of system 100 (e.g., CTF 135) via Remote
Authentication Dial-In User Service (RADIUS) protocol mechanisms
(e.g., messaging, signaling, etc.) or Diameter protocol. FIG. 1
illustrates AAA server 145 communicating with CTF 135 via the
RADIUS protocol. HSS 150 may be capable of
interfacing/communicating with other elements of system 100 (e.g.,
CTF 135) via 3GPP S6a interface mechanisms, S6a-based interface
mechanisms (e.g., for architectures that may involve interfaces
based on, but not strictly adhering to, 3GPP defined S6a interface
mechanisms), Application Programming Interface (API) mechanisms
(e.g., for messaging, signaling, etc. that may be defined by an
enterprise, 3rd-party, application, etc.), fabric-defined
interfaces (e.g., as may be defined by an enterprise), combinations
thereof, and/or the like. FIG. 1 illustrates HSS 150 communicating
with CTF 135 via one or more 3GPP S6a interface mechanisms or
S6a-based interface mechanisms.
[0039] Switches 155(1) and 155(2), network nodes 160(1)-160(4), and
border node 165 may transmit user plane packets between APs
125(1)-125(3) and DN 120. Switch 155(1) may be any suitable network
node configured to obtain/provide network communications (e.g.,
packets) from/to APs 125(1) and 125(2). Switch 155(2) may be any
suitable network node configured to obtain/provide network
communications (e.g., packets) from/to AP 125(3). Network nodes
160(1)-160(4) may be any suitable network node(s) configured to
transmit network communications between switches 155(1) and 155(2)
and border node 165. Border node 165 may be any suitable network
node associated with DN 120 configured to obtain/provide network
communications from/to DN 120. For instance, border node 165 may be
an edge router for network fabric 115. In one example, switches
155(1) and 155(2) and/or border node 165 are IP forwarding elements
that support the LISP ingress/egress Tunnel Router (xTR) functions.
Switches 155(1) or 155(2) may also be referred to interchangeably
as a "fabric edge node" and border node 165 may also be referred to
interchangeably as a "fabric border node." In one example, network
nodes 160(1)-160(4) may be underlay network elements unaware of
LISP operations.
[0040] Although various interconnections/interfaces among various
elements of network fabric 115 are illustrated in FIG. 1 (e.g.,
among control plane entities such as CTF 135, MS 140, AAA server
145, and HSS 150, and/or among user plane entities such as switches
155(1) and 155(2), network nodes 160(1)-160(4), and border node
165), it is to be understood that any elements of network fabric
115 may be interconnected and/or interface using any wired and/or
wireless connections to facilitate communications, operations, etc.
among the elements as discussed for techniques described
herein.
[0041] FIG. 1 illustrates two handover scenarios, represented by
arrows 170(1) and 170(2). In handover scenario 170(1), UE 105
transitions from AP 125(1) to AP 125(2) (e.g., via an S1AP based
handover procedure or an X2 based handover procedure). As explained
in greater detail below, because APs 125(1) and 125(2) are both
attached to switch 155(1), an RLOC change may not be necessary
(e.g., the RLOC of switch 155(1) may be utilized throughout the
handover process). Accordingly, handover scenario 170(1) may be
referred to as an "intra-AP handover scenario." In handover
scenario 170(2), UE 105 transitions from AP 125(1) to AP 125(3)
(e.g., via an S1AP based handover procedure or an X2 based handover
procedures). As explained in greater detail below, because APs
125(1) and 125(3) are attached to different switches (switches
155(1) and 155(2), respectively), an RLOC change may be utilized
(e.g., the RLOC of switch 155(1) may be replaced with the RLOC of
switch 155(2) during the handover process). Accordingly, handover
scenario 170(2) may be referred to as an "inter-AP handover
scenario."
[0042] The AP from which UE 105 is transitioning may be referred to
as a "source AP," and the AP to which UE 105 is transitioning may
be referred to as a "target AP." Thus, in handover scenario 170(1),
AP 125(1) is the source AP and AP 125(2) is the target AP. In
handover scenario 170(2), AP 125(1) is the source AP and AP 125(3)
is the target AP. In either handover scenario 170(1) or 170(2),
traditionally there would be a risk of packet loss while UE 105 is
transitioning from the source AP to the target AP. For example,
downlink packets from DN 120 destined for UE 105 could be routed to
AP 125(1) after AP 125(1) is no longer configured to provide
downlink packets to UE 105, and those packets could be lost to UE
105. Such packet loss during handover can cause poor user
experience.
[0043] Accordingly, CTF 135 includes handover support logic 175 to
enable downlink packet replication to support handovers in system
100. Handover support logic 175 may cause CTF 135 to effectuate
replication of downlink packets during a handover and forwarding of
the downlink packets to both the source AP and the target AP. Thus,
regardless of whether UE 105 can communicate with the source AP or
target AP, at least one of the source or target APs may provide the
downlink packets to UE 105, thereby minimizing packet loss. In
order to achieve downlink packet replication in system 100, CTF 135
may effectively build and manage an interworking between 3GPP
control plane elements and LISP forwarding elements to ensure the
states in the forwarding plane of network fabric 115 remain
accurate. Thus, system 100 may extend support of S1AP and X2
handover procedures to enterprise environments utilizing private
cellular access in the LISP-based user plane.
[0044] With continued reference to FIG. 1, FIG. 2 illustrates a
flowchart of an example method 200 for downlink packet replication
to support an S1AP handover. Method 200 may apply to either of
handover scenarios 170(1) or 170(2). Operation 210 relates to
handover preparation, and operation 220 relates to handover
execution. More specifically, at operation 210, system 100 prepares
to replicate downlink packets destined for UE 105 and forward the
downlink packets to the source AP and to the target AP. At
operation 220, system 100 replicates the downlink packets and
forwards the downlink packets to the source AP and to the target
AP.
[0045] Method 200 may be realized through any of at least three
mechanisms to ensure zero (or near-zero) packet loss during S1AP
handover. The first mechanism may involve packet replication on a
fabric node that forwards the downlink packets to the source and
target APs. The second and third mechanisms may involve packet
replication on the source AP, which may utilize a tunnel (e.g., a
data forwarding tunnel) to forward the downlink packets to the
target AP. In one example, the first mechanism may be particularly
advantageous because replication occurs on a fabric node (e.g., a
network fabric switch) instead of involving the RAN elements (e.g.,
the source AP). However, it will be appreciated that all three
mechanisms may be advantageous depending on the particular use case
in which they are implemented.
[0046] More specifically, the first and second mechanisms may
involve CTF 135 obtaining a notification that a handover is to
occur for UE 105 from a source AP to a target AP; identifying an
RLOC for a tunnel router associated with the source AP and an RLOC
for a tunnel router associated with the target AP; and providing,
to MS 140, a registration message including a mapping of an EID of
UE 105 to the RLOC for the tunnel router associated with the source
AP and the RLOC for the tunnel router associated with the target
AP. Based on the registration message, MS 140 causes downlink
packets destined for UE 105 to be replicated and provided to the
source AP and to the target AP. As explained in greater detail
below, the first mechanism may involve replication of downlink
packets on a fabric node, and the second mechanism may involve
replicating downlink packets on the source AP using the target AP
as a secondary AP.
[0047] The third mechanism may involve CTF 135 obtaining a
notification that a handover is to occur for UE 105 from the source
AP to the target AP; providing, to the target AP, an identification
of the source AP that causes the target AP to decapsulate
encapsulated downlink packets destined for UE 105, where the
encapsulated downlink packets destined for UE 105 are encapsulated
with an outer header identifying the source AP as a source of the
encapsulated downlink packets destined for UE 105 and further
identifying the target AP as a destination of the encapsulated
downlink packets destined for UE 105; and providing, to the source
AP, an indication to replicate downlink packets destined for UE 105
to generate a first copy of the downlink packets destined for UE
105 and a second copy of the downlink packets destined for UE 105,
and encapsulate the first copy of the downlink packets destined for
UE 105 with the outer header to generate the encapsulated downlink
packets destined for UE 105. Thus, as explained in greater detail
below, the third mechanism may involve replicating downlink packets
on the source AP using packet encapsulation. The third mechanism
may also be referred to as "double encapsulation" because it may
involve encapsulating downlink packets destined for UE 105 twice:
the first layer of encapsulation to enable LISP routing and the
second layer of encapsulation to enable the third mechanism.
[0048] With continued reference to FIGS. 1 and 2, FIGS. 3-6
illustrate call flows relating to the first mechanism(s), FIGS.
7-10 illustrate call flows relating to the second mechanism(s), and
FIGS. 11-14 illustrate call flows relating to the third
mechanism(s). FIGS. 3, 7, and 11 relate to operation 210 (handover
preparation) in handover scenario 170(1), FIGS. 4, 8, and 12 relate
to operation 220 (handover execution) in handover scenario 170(1),
FIGS. 5, 9, and 13 relate to operation 210 (handover preparation)
in handover scenario 170(2), and FIGS. 6, 10, and 14 relate to
operation 220 (handover execution) in handover scenario 170(2).
[0049] FIG. 3 illustrates a call flow diagram of an example method
300 of handover preparation utilizing the first mechanism in
handover scenario 170(1). At operation 302, AP 125(1) registers
with CTF 135. At operation 304, an access Virtual Extensible Local
Area Network (VXLAN) tunnel is established between AP 125(1) and
switch 155(1). This access VXLAN tunnel may be referred to as
"AT0." At operation 306, AP 125(2) registers with CTF 135. At
operation 308, an access VXLAN tunnel is established between AP
125(2) and switch 155(1). This access VXLAN tunnel may be referred
to as "AT1." At operation 310, AP 125(3) registers with CTF 135. At
operation 312, an access VXLAN tunnel is established between AP
125(3) and switch 155(1). This access VXLAN tunnel may be referred
to as "AT2."
[0050] At operation 314, UE 105 enters active mode. At operation
316, AP 125(1) obtains the default bearer for UE 105. At operation
318, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 320, CTF 135 obtains the default bearer for UE 105. At
operation 322, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0051] At operation 324, AP 125(1) obtains a Radio Resource Control
(RRC) measurement report from UE 105. At operation 326, AP 125(1)
determines that a handover needs to be performed, selects the
target cell (e.g., selects AP 125(2) as the target AP), and derives
KeNB* (in the 4G case). KeNB* is the transition key derived at the
source AP (here, AP 125(1)) based on the current KeNB and the
target Physical Cell ID (PCI). KeNB* is then passed to the target
AP (here, AP 125(2)) to derive a new KeNB for use by the target AP
(here, AP 125(2)). At operation 328, CTF 135 obtains a notification
that a handover is to occur for UE 105 from AP 125(1) to AP 125(2).
The notification may include, for example, an identification of AP
125(2), the target Tracking Area Identifier (TAI) for AP 125(2)
(e.g., identifying tracking area 110), and a Source to Target
Transparent Container. The Source to Target Transparent Container
permits the source AP (here, AP 125(1)) to send UE bearer
information to the target AP (here, AP 125(2)). This operation may
be transparent to CTF 135. At operation 330, CTF 135 provides, to
AP 125(2), a handover request including the Source to Target
Transparent Container. At operation 332, AP 125(2) generates Access
Stratum (AS) keys from KeNB* and allocates a Cell Radio Network
Temporary Identifier (C-RNTI) for UE 105. At operation 334, CTF 135
obtains a handover request acknowledgement from AP 125(2).
[0052] At operation 336, CTF 135 identifies the RLOC for the tunnel
router associated with AP 125(1) and the RLOC for the tunnel router
associated with AP 125(2). Because method 300 involves handover
scenario 170(1), the tunnel router associated with AP 125(1) and
the tunnel router associated with AP 125(2) are a single tunnel
router, i.e., switch 155(1). Thus, CTF 135 identifies the RLOC for
switch 155(1). At operation 338, CTF 135 provides a registration
message (instead of a General Packet Radio Service (GPRS) Tunneling
Protocol (GTP) Create Indirect Data Forwarding Tunnel Request) to
MS 140. The registration message includes a mapping of the EID of
UE 105 to the RLOC of switch 155(1). Thus, MS 140 has a single
EID-to-RLOC mapping entry that maps the EID of UE 105 to the RLOC
of switch 155(1).
[0053] The registration message further includes an indication for
switch 155(1) to replicate downlink packets destined for UE 105 to
generate a first copy of the downlink packets destined for UE 105
and a second copy of the downlink packets destined for UE 105,
provide the first copy of the downlink packets destined for UE 105
to AP 125(1), and provide the second copy of the downlink packets
destined for UE 105 to AP 125(2). The registration message may also
include the IP address of AP 125(1) and the IP address of AP
125(2). In one specific example, the registration message may
include a Layer 2 (L2) VXLAN Network ID (VNID), an EID set to the
MAC address of UE 105, an RLOC set to the RLOC of switch 155(1),
and a TLV identifying both the IP address of AP 125(1) and the IP
address of AP 125(2) as well as the appropriate Security Group Tag
(SGT).
[0054] Based on the registration message, MS 140 causes downlink
packets destined for UE 105 to be replicated and provided to both
AP 125(1) and AP 125(2). At operation 340, MS 140 provides, to
switch 155(1), a notification message including the mapping of the
EID of UE 105 to the RLOC of switch 155(1) and the indication for
switch 155(1) to replicate downlink packets destined for UE 105 to
generate the first copy of the downlink packets destined for UE 105
and the second copy of the downlink packets destined for UE 105,
provide the first copy of the downlink packets destined for UE 105
to AP 125(1), and provide the second copy of the downlink packets
destined for UE 105 to AP 125(2). In one specific example, MS 140
provides, to switch 155(1), a proxy notify message including the L2
VNID, the EID set to the MAC address of UE 105, the RLOC set to the
RLOC of switch 155(1), and the TLV identifying both the IP address
of AP 125(1) and the IP address of AP 125(2) as well as the
appropriate SGT.
[0055] At operation 342, based on the notification message, switch
155(1) maps the MAC address of UE 105 to both AT0 and AT1. This
causes switch 155(1) to replicate downlink packets destined for UE
105 to generate the first copy of the downlink packets destined for
UE 105 and the second copy of the downlink packets destined for UE
105, provide the first copy of the downlink packets destined for UE
105 to AP 125(1), and provide the second copy of the downlink
packets destined for UE 105 to AP 125(2). For L2-based LISP
overlays, switch 155(1) creates forwarding entries with the virtual
MAC (vMAC) address of UE 105 as reachable over both AT0 and AT1,
with a replication rule enabled. For Layer 3 (L3) based LISP
overlays, switch 155(1) may create forwarding entries with the EID
(e.g., IP address) of UE 105 as reachable over both AT0 and
AT1.
[0056] At operations 344 and 346, MS 140 provides publications to
switch 155(2) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(1). At operation 348, CTF 135 provides a
handover command to AP 125(1). At this point, border node 165 is
configured to provide downlink packets destined for UE 105 to
switch 155(1), which is configured to provide the downlink packets
to APs 125(1) and 125(2). AP 125(1) is in turn configured to
provide the downlink packets to UE 105, and AP 125(2) is configured
to buffer the downlink packets.
[0057] FIG. 4 illustrates a call flow diagram of an example method
400 of handover execution utilizing the first mechanism in handover
scenario 170(1). Initially, border node 165 may obtain downlink
packets from DN 120. The downlink packets may be destined for UE
105 (e.g., the downlink packets may identify the MAC or IP address
of UE 105 as the destination addresses of the downlink packets). At
operation 402, border node 165 provides (e.g., forwards) the
downlink packets over a VXLAN tunnel to switch 155(1).
[0058] Based on the notification message, switch 155(1) replicates
the downlink packets to generate a first copy of the downlink
packets and a second copy of the downlink packets. At operation
404, switch 155(1) provides the first copy of the downlink packets
to AP 125(1) over AT0, and at operation 406, switch 155(1) provides
the second copy of the downlink packets to AP 125(2) over AT1. At
operation 408, AP 125(1) provides the first copy of the downlink
packets to UE 105. At operation 410, AP 125(2) buffers the second
copy of the downlink packets until AP 125(2) obtains a handover
confirmation from UE 105.
[0059] At operation 412, AP 125(1) provides an RRC Connection
Reconfiguration Request to UE 105. At operation 414, CTF 135
obtains an AP status transfer from AP 125(1). At operation 416, AP
125(2) obtains an indication that the RRC connection
reconfiguration is complete. The indication may include the target
C-RNTI. At operation 418, AP 125(2) obtains the handover
confirmation from UE 105, and the handover procedure is complete.
At this point, AP 125(2) is configured to forward the buffered
downlink packets to UE 105 and obtain uplink packets from UE
105.
[0060] At operation 420, AP 125(2) forwards the buffered downlink
packets to UE 105. Thus, UE 105 obtains downlink packets from both
AP 125(1) and AP 125(2) during the handover procedure to help
ensure that no downlink packets are lost. If UE 105 obtains
identical copies of a given downlink packet, UE 105 may simply drop
one of the identical copies. At operation 422, AP 125(2) obtains
the uplink packets from UE 105. The uplink packets may be destined
for DN 120. At operation 424, switch 155(1) may obtain the uplink
packets from AP 125(2). At operation 426, switch 155(1) may provide
the uplink packets to border node 165, which may in turn provide
the uplink packets to DN 120.
[0061] At operation 428, CTF 135 obtains a notification that the
handover has occurred from AP 125(2). At operation 430, CTF 135
starts a handover release timer. At operation 432, CTF 135 provides
a registration message (instead of a modify bearer request) to MS
140. The registration message includes a mapping of the EID of UE
105 to the RLOC of switch 155(1). The registration message further
includes an indication that the RLOC of switch 155(1) is associated
with AP 125(2). In one specific example, the registration message
may include a L2 VNID, an EID set to the MAC address of UE 105, an
RLOC set to the RLOC of switch 155(1), and a TLV identifying the IP
address of AP 125(2) and the appropriate SGT.
[0062] At operation 434, based on the registration message, MS 140
provides, to switch 155(1), a notification message including the
mapping of the EID of UE 105 to the RLOC of switch 155(1) and an
indication for switch 155(1) to provide downlink packets destined
for UE 105 to AP 125(2). In one specific example, MS 140 provides,
to switch 155(1), a proxy notify message including the L2 VNID, the
EID set to the MAC address of UE 105, the RLOC set to the RLOC of
switch 155(1), and the TLV identifying the IP address of AP 125(2)
and the appropriate SGT. At operation 436, based on the
notification message, switch 155(1) maps the MAC address of UE 105
to AT1. This causes switch 155(1) to forward downlink packets
destined for UE 105 to AP 125(2).
[0063] At operations 438 and 440, MS 140 provides publications to
switch 155(2) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(1). At operation 442, switch 155(1)
obtains, from border node 165, downlink packets destined for UE
105. At operation 444, switch 155(1) provides, to AP 125(2), the
downlink packets destined for UE 105. At operation 446, AP 125(2)
provides the downlink packets to UE 105. At operation 448, CTF 135
determines that the handover release timer has expired. At
operation 450, in response to the handover release timer expiring,
CTF 135 provides a UE context release command to AP 125(1). At
operation 452, CTF 135 obtains a UE context release complete
message from AP 125(1).
[0064] FIG. 5 illustrates a call flow diagram of an example method
500 of handover preparation utilizing the first mechanism in
handover scenario 170(2). At operation 502, AP 125(1) registers
with CTF 135. At operation 504, access VXLAN tunnel AT0 is
established between AP 125(1) and switch 155(1). At operation 506,
AP 125(2) registers with CTF 135. At operation 508, access VXLAN
tunnel AT1 is established between AP 125(2) and switch 155(1). At
operation 510, AP 125(3) registers with CTF 135. At operation 512,
access VXLAN tunnel AT2 is established between AP 125(3) and switch
155(1).
[0065] At operation 514, UE 105 enters active mode. At operation
516, AP 125(1) obtains the default bearer for UE 105. At operation
518, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 520, CTF 135 obtains the default bearer for UE 105. At
operation 522, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0066] At operation 524, AP 125(1) obtains an RRC measurement
report from UE 105. At operation 526, AP 125(1) determines that a
handover needs to be performed, selects the target cell (e.g.,
selects AP 125(3) as the target AP), and derives KeNB* (in the 4G
case). At operation 528, CTF 135 obtains a notification that a
handover is to occur for UE 105 from AP 125(1) to AP 125(3). The
notification may include, for example, an identification of AP
125(3), the target TAI for AP 125(3) (e.g., identifying tracking
area 110), and a Source to Target Transparent Container. At
operation 530, CTF 135 provides, to AP 125(3), a handover request
including the Source to Target Transparent Container. At operation
532, AP 125(3) generates AS keys from KeNB* and allocates a C-RNTI
for UE 105. At operation 534, CTF 135 obtains a handover request
acknowledgement from AP 125(3).
[0067] At operation 536, CTF 135 identifies the RLOC for the tunnel
router associated with AP 125(1) and the RLOC for the tunnel router
associated with AP 125(3). Because method 500 involves handover
scenario 170(2), the tunnel router associated with AP 125(1) (i.e.,
switch 155(1)) is different from the tunnel router associated with
AP 125(3) (i.e., switch 155(2)). Thus, CTF 135 identifies the RLOCs
for switches 155(1) and 155(2). At operation 538, CTF 135 provides
a registration message (instead of a GTP Create Indirect Data
Forwarding Tunnel Request) to MS 140. The registration message
includes a mapping of the EID of UE 105 to the RLOC of switch
155(1) and the RLOC of switch 155(2). Thus, MS 140 has multiple
EID-to-RLOC bindings for UE 105. In particular, the EID of UE 105
may be mapped both to the RLOC of switch 155(1) and the RLOC of
switch 155(2).
[0068] The registration message further includes an indication for
border node 165 to replicate downlink packets destined for UE 105
to generate a first copy of the downlink packets destined for UE
105 and a second copy of the downlink packets destined for UE 105,
provide the first copy of the downlink packets destined for UE 105
to switch 155(1), and provide the second copy of the downlink
packets destined for UE 105 to switch 155(2). The registration
message may also include the IP address of AP 125(1) and the IP
address of AP 125(3). In one specific example, the registration
message may include a L2 VNID, an EID set to the MAC address of UE
105, an RLOC set to the RLOC of switch 155(1), a TLV associated
with the RLOC of switch 155(1) that identifies both the IP address
of AP 125(1) and a corresponding SGT, an RLOC set to the RLOC of
switch 155(2), and a TLV associated with the RLOC of switch 155(2)
that identifies both the IP address of AP 125(3) and a
corresponding SGT.
[0069] Based on the registration message, MS 140 causes downlink
packets destined for UE 105 to be replicated and provided to both
AP 125(1) and AP 125(3). At operation 540, MS 140 provides a
notification message to switch 155(1). In one specific example, MS
140 provides a proxy notify message including the L2 VNID for the
MAC address of UE 105, the RLOC set to the RLOC of switch 155(1)
and the TLV associated with the RLOC of switch 155(1) that
identifies both the IP address of AP 125(1) and the corresponding
SGT. At operation 542, based on the notification message, switch
155(1) maps the MAC address of UE 105 to AT0. This causes switch
155(1) to forward downlink packets destined for UE 105 to AP
125(1). For L2-based LISP overlays, switch 155(1) creates
forwarding entries with the vMAC address of UE 105 as reachable
over AT0. For L3 based LISP overlays, switch 155(1) may create
forwarding entries with the EID (e.g., IP address) of UE 105 as
reachable over AT0.
[0070] At operation 544, MS 140 provides a notification message to
switch 155(2). In one specific example, MS 140 provides a proxy
notify message including the L2 VNID for the MAC address of UE 105,
the RLOC set to the RLOC of switch 155(2) and the TLV associated
with the RLOC of switch 155(2) that identifies both the IP address
of AP 125(3) and the corresponding SGT. At operation 546, based on
the notification message, switch 155(2) maps the MAC address of UE
105 to AT2. This causes switch 155(2) to forward downlink packets
destined for UE 105 to AP 125(3). For L2-based LISP overlays,
switch 155(2) creates forwarding entries with the vMAC address of
UE 105 as reachable over AT2. For L3 based LISP overlays, switch
155(2) may create forwarding entries with the EID (e.g., IP
address) of UE 105 as reachable over AT2.
[0071] At operation 548, MS 140 provides, to border node 165, a
publication including the mapping of the EID of UE 105 to the RLOCs
of switches 155(1) and 155(2) and the indication for border node
165 to replicate downlink packets destined for UE 105 to generate
the first copy of the downlink packets destined for UE 105 and the
second copy of the downlink packets destined for UE 105, provide
the first copy of the downlink packets destined for UE 105 to
switch 155(1), and provide the second copy of the downlink packets
destined for UE 105 to switch 155(2). In one specific example, the
publication includes the L2 VNID for the MAC address of UE 105 and
the RLOC set to both the RLOC of switch 155(1) and the RLOC of
switch 155(2).
[0072] This causes border node 165 to replicate downlink packets
destined for UE 105 to generate the first copy of the downlink
packets destined for UE 105 and the second copy of the downlink
packets destined for UE 105, provide the first copy of the downlink
packets destined for UE 105 to switch 155(1), and provide the
second copy of the downlink packets destined for UE 105 to switch
155(2). Thus, at this point, border node 165 is configured to
provide downlink packets destined for UE 105 to switches 155(1) and
155(2). Switch 155(1) is configured to provide the downlink packets
to AP 125(1), which is in turn configured to provide the downlink
packets to UE 105. Switch 155(2) is configured to provide the
downlink packets to AP 125(3), which is in turn configured to
buffer the downlink packets. At operation 550, CTF 135 provides a
handover command to AP 125(1).
[0073] FIG. 6 illustrates a call flow diagram of an example method
600 of handover execution utilizing the first mechanism in handover
scenario 170(2). Initially, border node 165 may obtain downlink
packets from DN 120. The downlink packets may be destined for UE
105 (e.g., the downlink packets may identify the MAC or IP address
of UE 105 as the destination addresses of the downlink packets).
Based on the publication, border node 165 replicates the downlink
packets to generate a first copy of the downlink packets and a
second copy of the downlink packets. At operation 602, border node
165 provides (e.g., forwards) the first copy of the downlink
packets to switch 155(1) over AT0, and at operation 604, border
node 165 provides (e.g., forwards) the second copy of the downlink
packets to switch 155(2) over AT2. At operation 606, switch 155(1)
provides the first copy of the downlink packets to AP 125(1), and
at operation 608, AP 125(1) provides the first copy of the downlink
packets to UE 105. At operation 610, switch 155(2) provides the
second copy of the downlink packets to AP 125(3), and at operation
612, AP 125(3) buffers the second copy of the downlink packets
until AP 125(3) obtains a handover confirmation from UE 105.
[0074] At operation 614, AP 125(1) provides an RRC Connection
Reconfiguration Request to UE 105. At operation 616, CTF 135
obtains an AP status transfer from AP 125(1). At operation 618, AP
125(3) obtains an indication that the RRC connection
reconfiguration is complete. The indication may include the target
C-RNTI. At operation 620, AP 125(3) obtains the handover
confirmation from UE 105, and the handover procedure is complete.
At this point, AP 125(3) is configured to forward the buffered
downlink packets to UE 105 and obtain uplink packets from UE
105.
[0075] At operation 622, AP 125(3) forwards the buffered downlink
packets to UE 105. Thus, UE 105 obtains downlink packets from both
AP 125(1) and AP 125(3) during the handover procedure to help
ensure that no downlink packets are lost. If UE 105 obtains
identical copies of a given downlink packet, UE 105 may simply drop
one of the identical copies. At operation 624, AP 125(3) obtains
the uplink packets from UE 105. The uplink packets may be destined
for DN 120. At operation 626, switch 155(2) may obtain the uplink
packets from AP 125(3). At operation 628, switch 155(2) may provide
the uplink packets to border node 165, which may in turn provide
the uplink packets to DN 120.
[0076] At operation 630, CTF 135 obtains a notification that the
handover has occurred from AP 125(3). At operation 632, CTF 135
starts a handover release timer. At operation 634, CTF 135 provides
a registration message (instead of a modify bearer request) to MS
140. The registration message includes a mapping of the EID of UE
105 to the RLOC of switch 155(2). The registration message further
includes an indication that the RLOC of switch 155(2) is associated
with AP 125(3). In one specific example, the registration message
may include a L2 VNID, an EID set to the MAC address of UE 105, an
RLOC set to the RLOC of switch 155(2), and a TLV identifying the IP
address of AP 125(3) and the appropriate SGT.
[0077] At operation 636, based on the registration message, MS 140
provides, to switch 155(2), a proxy notify message including the L2
VNID for the MAC address of UE 105, the EID set to the MAC address
of UE 105, the RLOC set to the RLOC of switch 155(2), and a TLV
identifying the IP address of AP 125(3) and the appropriate SGT. At
operation 638, switch 155(2) maps the MAC address of UE 105 to AT2.
This causes switch 155(1) to forward downlink packets destined for
UE 105 to AP 125(3). At operation 640, MS 140 provides, to switch
155(1), a publication that includes the L2 VNID for the MAC address
of UE 105 and the RLOC set to the RLOC of switch 155(2).
[0078] At operation 642, based further on the registration message,
MS 140 provides, to border node 165, a publication including the
mapping of the EID of UE 105 to the RLOC of switch 155(2) and an
indication for border node 165 to provide downlink packets destined
for UE 105 to switch 155(2). In one specific example, MS 140
provides, to border node 165, a publication including the L2 VNID
for the MAC address of UE 105 and the RLOC set to the RLOC of
switch 155(2).
[0079] At operation 644, based on the publication, border node 165
provides downlink packets destined for UE 105 to switch 155(2). At
operation 646, switch 155(2) provides, to AP 125(3), the downlink
packets destined for UE 105. At operation 648, AP 125(3) provides
the downlink packets to UE 105. At operation 650, CTF 135
determines that the handover release timer has expired. At
operation 652, in response to the handover release timer expiring,
CTF 135 provides a UE context release command to AP 125(1). At
operation 654, CTF 135 obtains a UE context release complete
message from AP 125(1).
[0080] FIG. 7 illustrates a call flow diagram of an example method
700 of handover preparation utilizing the second mechanism in
handover scenario 170(1). At operation 702, AP 125(1) registers
with CTF 135. At operation 704, access VXLAN tunnel AT0 is
established between AP 125(1) and switch 155(1). At operation 706,
AP 125(2) registers with CTF 135. At operation 708, access VXLAN
tunnel AT1 is established between AP 125(2) and switch 155(1). At
operation 710, AP 125(3) registers with CTF 135. At operation 712,
access VXLAN tunnel AT2 is established between AP 125(3) and switch
155(1).
[0081] At operation 714, UE 105 enters active mode. At operation
716, AP 125(1) obtains the default bearer for UE 105. At operation
718, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 720, CTF 135 obtains the default bearer for UE 105. At
operation 722, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0082] At operation 724, AP 125(1) obtains an RRC measurement
report from UE 105. At operation 726, AP 125(1) determines that a
handover needs to be performed, selects the target cell (e.g.,
selects AP 125(2) as the target AP), and derives KeNB* (in the 4G
case). At operation 728, CTF 135 obtains a notification that a
handover is to occur for UE 105 from AP 125(1) to AP 125(2). The
notification may include, for example, an identification of AP
125(2), the target TAI for AP 125(2) (e.g., identifying tracking
area 110), and a Source to Target Transparent Container. At
operation 730, CTF 135 provides, to AP 125(2), a handover request
including the Source to Target Transparent Container. At operation
732, AP 125(2) generates AS keys from KeNB* and allocates a C-RNTI
for UE 105. At operation 734, CTF 135 obtains a handover request
acknowledgement from AP 125(2).
[0083] At operation 736, CTF 135 identifies the RLOC for the tunnel
router associated with AP 125(1) and the RLOC for the tunnel router
associated with AP 125(2). Because method 700 involves handover
scenario 170(1), the tunnel router associated with AP 125(1) and
the tunnel router associated with AP 125(2) are a single tunnel
router, i.e., switch 155(1). Thus, CTF 135 identifies the RLOC for
switch 155(1). At operation 738, CTF 135 provides a registration
message (instead of a GTP Create Indirect Data Forwarding Tunnel
Request) to MS 140. The registration message includes a mapping of
the EID of UE 105 to the RLOC of switch 155(1). Thus, MS 140 has a
single EID-to-RLOC mapping entry that maps the EID of UE 105 to the
RLOC of switch 155(1).
[0084] The registration message further includes an indication that
the AP 125(2) is a secondary AP. A secondary AP may be an AP that
is designated for use when a primary AP cannot or should not be
used, for example, when a downlink packet destined for a UE is
received from the primary AP. When that occurs, it may be assumed
that the primary AP, for any given reason, cannot forward the
downlink packet to the UE. As such, when the downlink packet is
received from the primary AP, the downlink packet may be forwarded
to the secondary AP, ad may thereby reach the UE via the secondary
AP instead of the primary AP.
[0085] Here, AP 125(2) is indicated as being the secondary AP and
AP 125(1) is by default the primary AP. Thus, the registration
message includes an indication that AP 125(2) is a secondary AP to
which switch 155(1) is to provide any downlink packets destined for
UE 105 that are obtained from AP 125(1). In one specific example,
the registration message may include an L2 VNID, an EID set to the
MAC address of UE 105, an RLOC set to the RLOC of switch 155(1),
and a TLV identifying the IP address of AP 125(2) and providing a
flag that the AP 125(2) is a secondary AP.
[0086] Based on the registration message, MS 140 causes downlink
packets destined for UE 105 to be replicated and provided to both
AP 125(1) and AP 125(2). At operation 740, MS 140 provides, to
switch 155(1), a notification message including the mapping of the
EID of UE 105 to the RLOC of switch 155(1) and the indication that
the AP 125(2) is the secondary AP. In one specific example, MS 140
provides, to switch 155(1), a proxy notify message including the L2
VNID, the EID set to the MAC address of UE 105, the RLOC set to the
RLOC of switch 155(1), and a TLV identifying the IP address of AP
125(2) and providing a flag that the AP 125(2) is a secondary
AP.
[0087] At operation 742, based on the notification message, switch
155(1) maps the MAC address of UE 105 to both AT0 and AT1. This
causes switch 155(1) to provide downlink packets destined for UE
105 to AP 125(1) over AT0, and further causes switch 155(1) to
provide any downlink packets obtained from AP 125(1) over AT0 to AP
125(2) over AT1. For L2-based LISP overlays, switch 155(1) creates
forwarding entries with the vMAC address of UE 105 as reachable
over both AT0 (designated as the primary access VXLAN tunnel) and
AT1 (designated as the secondary access VXLAN tunnel). For L3-based
LISP overlays, switch 155(1) may create forwarding entries with the
EID (e.g., IP address) of UE 105 as reachable over both AT0
(designated as the primary access VXLAN tunnel or primary path) and
AT1 (designated as the secondary access VXLAN tunnel or secondary
path). Thus, upon receiving a downlink packet that has an L2 MAC
address matching the vMAC address entry (in the L2 case) or a
destination IP address matching the EID of UE 105, switch 155(1) is
configured to send that downlink packet to AP 125(1) by default,
because AP 125(1) is the primary AP. But if the downlink packet is
received from AP 125(1), switch 155(1) is configured to send the
downlink packet to AP 125(2), because AP 125(2) is the secondary
AP.
[0088] At operations 744 and 746, MS 140 provides publications to
switch 155(2) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(1). Thus, MS 140 delivers the single
EID-to-RLOC mapping entry to switch 155(2) and border node 165. At
operation 748, CTF 135 provides a handover command to AP 125(1). At
this point, border node 165 is configured to provide downlink
packets destined for UE 105 to switch 155(1) over AT0. Switch
155(1) is in turn configured to provide the downlink packets to AP
125(1) by default (e.g., if the downlink packets are obtained from
border node 165), and to AP 125(2) if the downlink packets destined
for UE 105 are obtained from AP 125(1).
[0089] FIG. 8 illustrates a call flow diagram of an example method
800 for handover execution utilizing the second mechanism in
handover scenario 170(1). Initially, border node 165 may obtain
downlink packets from DN 120. The downlink packets may be destined
for UE 105 (e.g., the downlink packets may identify the MAC or IP
address of UE 105 as the destination addresses of the downlink
packets). At operation 802, border node 165 provides (e.g.,
forwards) the downlink packets over a VXLAN tunnel to switch
155(1). At operation 804, switch 155(1) provides the downlink
packets destined for UE 105 to AP 125(1).
[0090] At operation 806, AP 125(1) replicates the downlink packets
to generate a first copy of the downlink packets and a second copy
of the downlink packets, and provides the first copy of the
downlink packets to switch 155(1) over AT0. At operation 808, AP
125(1) provides the second copy of the downlink packets to UE 105.
At operation 810, based on the notification message, switch 155(1)
provides (e.g., forwards) the first copy of the downlink packets to
AP 125(2) over AT1. At operation 812, AP 125(2) buffers the second
copy of the downlink packets until AP 125(2) obtains a handover
confirmation from UE 105.
[0091] At operation 814, AP 125(1) provides an RRC Connection
Reconfiguration Request to UE 105. At operation 816, CTF 135
obtains an AP status transfer from AP 125(1). At operation 818, AP
125(2) obtains an indication that the RRC connection
reconfiguration is complete. The indication may include the target
C-RNTI. At operation 820, AP 125(2) obtains the handover
confirmation from UE 105, and the handover procedure is complete.
At this point, AP 125(2) is configured to forward the buffered
downlink packets to UE 105 and obtain uplink packets from UE
105.
[0092] At operation 822, AP 125(2) forwards the buffered downlink
packets to UE 105. Thus, UE 105 obtains downlink packets from both
AP 125(1) and AP 125(2) during the handover procedure to help
ensure that no downlink packets are lost. If UE 105 obtains
identical copies of a given downlink packet, UE 105 may simply drop
one of the identical copies. At operation 824, AP 125(2) obtains
the uplink packets from UE 105. The uplink packets may be destined
for DN 120. At operation 826, switch 155(1) may obtain the uplink
packets from AP 125(2). At operation 828, switch 155(1) may provide
the uplink packets to border node 165, which may in turn provide
the uplink packets to DN 120.
[0093] At operation 830, CTF 135 obtains a notification that the
handover has occurred from AP 125(2). At operation 832, CTF 135
starts a handover release timer. At operation 834, CTF 135 provides
a registration message (instead of a modify bearer request) to MS
140. The registration message includes a mapping of the EID of UE
105 to the RLOC of switch 155(1). The registration message further
includes an indication that the RLOC of switch 155(1) is associated
with AP 125(2). In one specific example, the registration message
may include a L2 VNID, an EID set to the MAC address of UE 105, an
RLOC set to the RLOC of switch 155(1), and a TLV identifying the IP
address of AP 125(2) and the appropriate SGT.
[0094] At operation 836, based on the registration message, MS 140
provides, to switch 155(1), a notification message including the
mapping of the EID of UE 105 to the RLOC of switch 155(1) and an
indication for switch 155(1) to provide downlink packets destined
for UE 105 to AP 125(2). In one specific example, MS 140 provides,
to switch 155(1), a proxy notify message including the L2 VNID, the
EID set to the MAC address of UE 105, the RLOC set to the RLOC of
switch 155(1), and the TLV identifying the IP address of AP 125(2)
and the appropriate SGT. At operation 838, based on the
notification message, switch 155(1) maps the MAC address of UE 105
to AT1. This causes switch 155(1) to forward downlink packets
destined for UE 105 to AP 125(2).
[0095] At operations 840 and 842, MS 140 provides publications to
switch 155(2) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(1). At operation 844, switch 155(1)
obtains, from border node 165, downlink packets destined for UE
105. At operation 846, switch 155(1) provides, to AP 125(2), the
downlink packets destined for UE 105. At operation 848, AP 125(2)
provides the downlink packets to UE 105. At operation 850, CTF 135
determines that the handover release timer has expired. At
operation 852, in response to the handover release timer expiring,
CTF 135 provides a UE context release command to AP 125(1). At
operation 854, CTF 135 obtains a UE context release complete
message from AP 125(1).
[0096] FIG. 9 illustrates a call flow diagram of an example method
900 of handover preparation utilizing the second mechanism in
handover scenario 170(2). At operation 902, AP 125(1) registers
with CTF 135. At operation 904, access VXLAN tunnel AT0 is
established between AP 125(1) and switch 155(1). At operation 906,
AP 125(2) registers with CTF 135. At operation 908, access VXLAN
tunnel AT1 is established between AP 125(2) and switch 155(1). At
operation 910, AP 125(3) registers with CTF 135. At operation 912,
access VXLAN tunnel AT2 is established between AP 125(3) and switch
155(1).
[0097] At operation 914, UE 105 enters active mode. At operation
916, AP 125(1) obtains the default bearer for UE 105. At operation
918, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 920, CTF 135 obtains the default bearer for UE 105. At
operation 922, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0098] At operation 924, AP 125(1) obtains an RRC measurement
report from UE 105. At operation 926, AP 125(1) determines that a
handover needs to be performed, selects the target cell (e.g.,
selects AP 125(3) as the target AP), and derives KeNB* (in the 4G
case). At operation 928, CTF 135 obtains a notification that a
handover is to occur for UE 105 from AP 125(1) to AP 125(3). The
notification may include, for example, an identification of AP
125(3), the target TAI for AP 125(3) (e.g., identifying tracking
area 110), and a Source to Target Transparent Container. At
operation 930, CTF 135 provides, to AP 125(3), a handover request
including the Source to Target Transparent Container. At operation
932, AP 125(3) generates AS keys from KeNB* and allocates a C-RNTI
for UE 105. At operation 934, CTF 135 obtains a handover request
acknowledgement from AP 125(3).
[0099] At operation 936, CTF 135 identifies the RLOC for the tunnel
router associated with AP 125(1) and the RLOC for the tunnel router
associated with AP 125(3). Because method 900 involves handover
scenario 170(2), the tunnel router associated with AP 125(1) (i.e.,
switch 155(1)) is different from the tunnel router associated with
AP 125(3) (i.e., switch 155(2)). Thus, CTF 135 identifies the RLOCs
for switches 155(1) and 155(2). At operation 938, CTF 135 provides
a registration message (instead of a GTP Create Indirect Data
Forwarding Tunnel Request) to MS 140. The registration message
includes a mapping of the EID of UE 105 to the RLOC of switch
155(1) and the RLOC of switch 155(2). Thus, MS 140 has multiple
EID-to-RLOC bindings for UE 105. In particular, the EID of UE 105
may be mapped both to the RLOC of switch 155(1) and the RLOC of
switch 155(2).
[0100] The registration message further includes an indication that
the AP 125(3) is a secondary AP. AP 125(1) may be the primary AP by
default. Thus, the registration message includes an indication that
AP 125(3) is a secondary AP to which switches 155(1) and 155(2) are
to provide any downlink packets destined for UE 105 that are
obtained from AP 125(1). In one specific example, the registration
message may include an L2 VNID, an EID set to the MAC address of UE
105, an RLOC set to the RLOC of switch 155(1), a TLV corresponding
to the RLOC of switch 155(1) that identifies the IP address of AP
125(1), an RLOC set to the RLOC of switch 155(2), and a TLV
corresponding to the RLOC of switch 155(2) that identifies the IP
address of AP 125(3) and provides a flag that the AP 125(3) is a
secondary AP.
[0101] Based on the registration message, MS 140 causes downlink
packets destined for UE 105 to be replicated and provided to both
AP 125(1) and AP 125(3). At operation 940, MS 140 provides, to
switch 155(1), a notification message including the mapping of the
EID of UE 105 to the RLOCs of switches 155(1) and 155(2) and the
indication that AP 125(3) is the secondary AP. In one specific
example, MS 140 provides, to switch 155(1), a proxy notify message
including the L2 VNID, the EID set to the MAC address of UE 105, an
RLOC set to the RLOC of switch 155(1), the TLV corresponding to the
RLOC of switch 155(1) that identifies the IP address of AP 125(1),
an RLOC set to the RLOC of switch 155(2), and a TLV corresponding
to the RLOC of switch 155(2) that identifies the IP address of AP
125(3) and provides a flag that the AP 125(3) is a secondary
AP.
[0102] At operation 942, based on the notification message, switch
155(1) maps the MAC address of UE 105 to AT0 and identifies the
RLOC of switch 155(2) as a secondary RLOC. This causes switch
155(1) to provide downlink packets destined for UE 105 to AP 125(1)
over AT0, and further causes switch 155(1) to provide any downlink
packets obtained from AP 125(1) over AT0 to AP 125(3). Thus, upon
receiving a downlink packet that has destination address set to the
MAC address of UE 105, switch 155(1) is configured to send that
downlink packet to AP 125(1) by default, because AP 125(1) is the
primary AP. But if the downlink packet is received from AP 125(1),
switch 155(1) is configured to send the downlink packet to switch
155(2), because the RLOC of switch 155(2) is the secondary
RLOC.
[0103] At operation 944, MS 140 provides, to switch 155(2), a
notification message including the mapping of the EID of UE 105 to
the RLOC of switch 155(2). In one specific example, MS 140
provides, to switch 155(2), a proxy notify message including the L2
VNID, the EID set to the MAC address of UE 105, an RLOC set to the
RLOC of switch 155(2), and a corresponding TLV that identifies the
IP address of AP 125(3). At operation 946, based on the
notification message, switch 155(2) maps the MAC address of UE 105
to AT2. This causes switch 155(2) to provide downlink packets
destined for UE 105 to AP 125(3) over AT2.
[0104] At operation 948, MS 140 provides a publication to border
node 165. The publication includes the L2 VNID for the MAC address
of UE 105 and the RLOC set to the RLOC of switch 155(1). At
operation 950, CTF 135 provides a handover command to AP 125(1). At
this point, border node 165 is configured to provide downlink
packets destined for UE 105 to switch 155(1) over AT0. Switch
155(1) is in turn configured to provide the downlink packets to AP
125(1) by default (e.g., if the downlink packets are obtained from
border node 165), and to switch 155(2) if the downlink packets
destined for UE 105 are obtained from AP 125(1). Switch 155(2) is
configured to provide the downlink packets destined for UE 105 to
AP 125(3), which is in turn configured to provide the downlink
packets to UE 105.
[0105] FIG. 10 illustrates a call flow diagram of an example method
1000 for handover execution utilizing the second mechanism in
handover scenario 170(2). Initially, border node 165 may obtain
downlink packets from DN 120. The downlink packets may be destined
for UE 105 (e.g., the downlink packets may identify the MAC or IP
address of UE 105 as the destination addresses of the downlink
packets). At operation 1002, border node 165 provides the downlink
packets to switch 155(1), and at operation 1004, switch 155(1)
provides the downlink packets to AP 125(1).
[0106] At operation 1006, AP 125(1) replicates the downlink packets
to generate a first copy of the downlink packets and a second copy
of the downlink packets, and provides the first copy of the
downlink packets to switch 155(1) over AT0. At operation 1008, AP
125(1) provides the second copy of the downlink packets to UE 105.
At operation 1010, based on the notification message, switch 155(1)
provides (e.g., forwards) the first copy of the downlink packets to
switch 155(2) because the RLOC of switch 155(2) is the secondary
RLOC. At operation 1012, switch 155(2) provides the first copy of
the downlink packets to AP 125(3). At operation 1014, AP 125(3)
buffers the second copy of the downlink packets until AP 125(3)
obtains a handover confirmation from UE 105.
[0107] At operation 1016, AP 125(1) provides an RRC Connection
Reconfiguration Request to UE 105. At operation 1018, CTF 135
obtains an AP status transfer from AP 125(1). At operation 1020, AP
125(3) obtains an indication that the RRC connection
reconfiguration is complete from UE 105. The indication may include
the target C-RNTI. At operation 1022, AP 125(3) obtains the
handover confirmation from UE 105, and the handover procedure is
complete. At this point, AP 125(3) is configured to forward the
buffered downlink packets to UE 105 and obtain uplink packets from
UE 105.
[0108] At operation 1024, AP 125(3) forwards the buffered downlink
packets to UE 105. Thus, UE 105 obtains downlink packets from both
AP 125(1) and AP 125(3) during the handover procedure to help
ensure that no downlink packets are lost. If UE 105 obtains
identical copies of a given downlink packet, UE 105 may simply drop
one of the identical copies. At operation 1026, AP 125(3) obtains
the uplink packets from UE 105. The uplink packets may be destined
for DN 120. At operation 1028, switch 155(2) may obtain the uplink
packets from AP 125(3). At operation 1030, switch 155(2) may
provide the uplink packets to border node 165, which may in turn
provide the uplink packets to DN 120.
[0109] At operation 1032, CTF 135 obtains a notification that the
handover has occurred from AP 125(3). At operation 1034, CTF 135
starts a handover release timer. At operation 1036, CTF 135
provides a registration message (instead of a modify bearer
request) to MS 140. The registration message includes a mapping of
the EID of UE 105 to the RLOC of switch 155(2). The registration
message further includes an indication that the RLOC of switch
155(2) is associated with AP 125(3). In one specific example, the
registration message may include a L2 VNID, an EID set to the MAC
address of UE 105, an RLOC set to the RLOC of switch 155(2), and a
TLV identifying the IP address of AP 125(3).
[0110] At operation 1038, based on the registration message, MS 140
provides, to switch 155(2), a notification message including the
mapping of the EID of UE 105 to the RLOC of switch 155(2), and an
indication to provide the downlink packets destined for UE 105 to
AP 125(3). In one specific example, the notification message may be
a proxy notify message including the L2 VNID, the EID set to the
MAC address of UE 105, the RLOC set to the RLOC of switch 155(2),
and a TLV identifying the IP address of AP 125(3). At operation
1040, switch 155(2) maps the MAC address of UE 105 to AT2. This
causes switch 155(2) to forward downlink packets destined for UE
105 to AP 125(3). For example, this may cause switch 155(2) to send
any downlink packets having a destination address set to the MAC
address of UE 105 to AP 125(3) over AT2.
[0111] At operations 1042 and 1044, MS 140 provides, to switch
155(1) and border node 165, respectively, a publication that
includes the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(2). At operation 1046, border node 165
provides downlink packets destined for UE 105 to switch 155(2). At
operation 1048, based on the notification message, switch 155(2)
provides, to AP 125(3), the downlink packets destined for UE 105.
At operation 1050, AP 125(3) provides the downlink packets to UE
105. At operation 1052, CTF 135 determines that the handover
release timer has expired. At operation 1054, in response to the
handover release timer expiring, CTF 135 provides a UE context
release command to AP 125(1). At operation 1056, CTF 135 obtains a
UE context release complete message from AP 125(1).
[0112] FIG. 11 illustrates a call flow diagram of an example method
1100 of handover preparation utilizing the third mechanism in
handover scenario 170(1). At operation 1102, AP 125(1) registers
with CTF 135. At operation 1104, access VXLAN tunnel AT0 is
established between AP 125(1) and switch 155(1). At operation 1106,
AP 125(2) registers with CTF 135. At operation 1108, access VXLAN
tunnel AT1 is established between AP 125(2) and switch 155(1). At
operation 1110, AP 125(3) registers with CTF 135. At operation
1112, access VXLAN tunnel AT2 is established between AP 125(3) and
switch 155(1).
[0113] At operation 1114, UE 105 enters active mode. At operation
1116, AP 125(1) obtains the default bearer for UE 105. At operation
1118, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 1120, CTF 135 obtains the default bearer for UE 105. At
operation 1122, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0114] At operation 1124, AP 125(1) obtains an RRC measurement
report from UE 105. At operation 1126, AP 125(1) determines that a
handover needs to be performed, selects the target cell (e.g.,
selects AP 125(2) as the target AP), and derives KeNB* (in the 4G
case). At operation 1128, CTF 135 obtains a notification that a
handover is to occur for UE 105 from AP 125(1) to AP 125(2). The
notification may include, for example, an identification of AP
125(2), the target TAI for AP 125(2) (e.g., identifying tracking
area 110), and a Source to Target Transparent Container.
[0115] At operation 1130, CTF 135 provides, to AP 125(2), an
indication to decapsulate encapsulated downlink packets destined
for UE 105. The encapsulated downlink packets destined for UE 105
are encapsulated with an outer header (e.g., a VXLAN header)
identifying AP 125(1) as a source of the encapsulated downlink
packets and further identifying AP 125(2) as a destination of the
encapsulated downlink packets. The indication may comprise a
handover request including the Source to Target Transparent
Container, and may further include an identification of AP
125(1).
[0116] At operation 1132, AP 125(2) generates AS keys from KeNB*
and allocates a C-RNTI for UE 105. At operation 1134, CTF 135
obtains a handover request acknowledgement from AP 125(2). At
operation 1136, AP 125(2) locally creates a VXLAN tunnel between AP
125(1) and AP 125(2). AP 125(2) is now configured to buffer
downlink packets destined for UE 105 obtained from AP 125(1) via
the VXLAN tunnel. At operation 1138, CTF 135 may prepare a GTP
Create Indirect Data Forwarding Tunnel Request, although this may
not be required.
[0117] At operation 1140, CTF 135 provides, to AP 125(1), an
indication to replicate downlink packets destined UE 105 to
generate a first copy of the downlink packets and a second copy of
the downlink packets, and encapsulate the first copy of the
downlink packets with the outer header to generate the encapsulated
downlink packets. The indication may comprise a handover command.
At 1142, AP 125(1) locally creates the VXLAN tunnel between AP
125(1) and AP 125(2). AP 125(1) is now configured to provide
downlink packets destined for UE 105 to AP 125(2) via the VXLAN
tunnel. Thus, the VXLAN tunnel between AP 125(1) and AP 125(2) is
now established.
[0118] FIG. 12 illustrates a call flow diagram of an example method
1200 of handover execution utilizing the third mechanism in
handover scenario 170(1). Initially, border node 165 may obtain
downlink packets from DN 120. The downlink packets may be destined
for UE 105 (e.g., the downlink packets may identify the MAC or IP
address of UE 105 as the destination addresses of the downlink
packets). At operation 1202, border node 165 provides the downlink
packets to switch 155(1). At operation 1204, switch 155(1) provides
the downlink packets destined for UE 105 to AP 125(1).
[0119] At operation 1206, AP 125(1) replicates the downlink packets
destined for UE 105 to generate the first copy of the downlink
packets and the second copy of the downlink packets, encapsulates
the first copy of the downlink packets with the outer header to
generate the encapsulated downlink packets, and provides the
encapsulated downlink packets to switch 155(1). AP 125(1) may
provide the encapsulated downlink packets to switch 155(1) over the
VXLAN tunnel. At operation 1208, AP 125(1) provides the second copy
of the downlink packets to UE 105.
[0120] Because method 1200 involves handover scenario 170(1), the
tunnel router associated with AP 125(1) and the tunnel router
associated with AP 125(2) are a single tunnel router, i.e., switch
155(1). Accordingly, at operation 1210, switch 155(1) identifies AP
125(2) as the destination of the encapsulated downlink packets
based on the outer header, which identifies AP 125(1) as the source
of the encapsulated downlink packets and AP 125(2) as the
destination of the encapsulated downlink packet. Switch 155(1)
further provides (e.g., forwards) the encapsulated downlink packets
to AP 125(1). At operation 1212, AP 125(2) decapsulates the
encapsulated downlink packets and buffers the first copy of the
downlink packets until AP 125(2) obtains a handover confirmation
from UE 105. AP 125(2) may decapsulate the encapsulated downlink
packets in response to determining that the outer header identifies
AP 125(1) as the source of the encapsulated downlink packets, and
based further on a previously obtained identification of AP 125(1)
as the source AP from which UE 105 is transitioning (e.g., at
operation 1130).
[0121] At operation 1214, AP 125(1) provides an RRC Connection
Reconfiguration Request to UE 105. At operation 1216, CTF 135
obtains an AP status transfer from AP 125(1). At operation 1218, AP
125(2) obtains an indication that the RRC connection
reconfiguration is complete. The indication may include the target
C-RNTI. At operation 1220, AP 125(2) obtains the handover
confirmation from UE 105, and the handover procedure is complete.
At this point, AP 125(2) is configured to forward the buffered
downlink packets to UE 105 and obtain uplink packets from UE
105.
[0122] At operation 1222, AP 125(2) provides the buffered downlink
packets to UE 105. Thus, UE 105 obtains downlink packets from both
AP 125(1) and AP 125(2) during the handover procedure to help
ensure that no downlink packets are lost. If UE 105 obtains
identical copies of a given downlink packet, UE 105 may simply drop
one of the identical copies. At operation 1224, AP 125(2) obtains
the uplink packets from UE 105. The uplink packets may be destined
for DN 120. At operation 1226, switch 155(1) may obtain the uplink
packets from AP 125(2). At operation 1228, switch 155(1) may
provide the uplink packets to border node 165, which may in turn
provide the uplink packets to DN 120.
[0123] At operation 1230, CTF 135 obtains a notification that the
handover has occurred from AP 125(2) and that AP 125(2) has stopped
or will stop decapsulating encapsulated downlink packets destined
for UE 105. At operation 1232, AP 125(2) locally deletes the VXLAN
tunnel between AP 125(1) and AP 125(2). At operation 1234, CTF 135
starts a handover release timer. At operation 1236, CTF 135
provides a registration message (instead of a modify bearer
request) to MS 140. The registration message includes a mapping of
the EID of UE 105 to the RLOC of switch 155(1). The registration
message further includes an indication that the RLOC of switch
155(1) is associated with AP 125(2). In one specific example, the
registration message may include a L2 VNID, an EID set to the MAC
address of UE 105, an RLOC set to the RLOC of switch 155(1), and a
TLV identifying the IP address of AP 125(2) and the appropriate
SGT.
[0124] At operation 1238, based on the registration message, MS 140
provides, to switch 155(1), a notification message including the
mapping of the EID of UE 105 to the RLOC of switch 155(1) and an
indication for switch 155(1) to provide downlink packets destined
for UE 105 to AP 125(2). In one specific example, MS 140 provides,
to switch 155(1), a proxy notify message including the L2 VNID, the
EID set to the MAC address of UE 105, the RLOC set to the RLOC of
switch 155(1), and the TLV identifying the IP address of AP 125(2)
and the appropriate SGT. At operation 1240, based on the
notification message, switch 155(1) maps the MAC address of UE 105
to AT1. This causes switch 155(1) to forward downlink packets
destined for UE 105 to AP 125(2).
[0125] At operations 1242 and 1244, MS 140 provides publications to
switch 155(2) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(1). At operation 1246, switch 155(1)
obtains, from border node 165, downlink packets destined for UE
105. At operation 1248, switch 155(1) provides, to AP 125(2), the
downlink packets destined for UE 105. At operation 1250, AP 125(2)
provides the downlink packets to UE 105. At operation 1252, CTF 135
determines that the handover release timer has expired.
[0126] At operation 1254, in response to the handover release timer
expiring, CTF 135 provides, to AP 125(1), an indication to stop
replicating the downlink packets destined UE 105 and encapsulating
the downlink packets with the outer header to generate the
encapsulated downlink packets. The indication may comprise a UE
context release command. At operation 1256, CTF 135 obtains a UE
context release complete message from AP 125(1). At operation 1258,
AP 125(1) locally deletes the VXLAN tunnel between AP 125(1) and AP
125(2). Thus, the VXLAN tunnel between AP 125(1) and AP 125(2) is
now removed, and AP 125(1) stops replicating the downlink packets
destined UE 105 and encapsulating the downlink packets with the
outer header to generate the encapsulated downlink packets.
[0127] FIG. 13 illustrates a call flow diagram of an example method
1300 of handover preparation utilizing the third mechanism in
handover scenario 170(2). At operation 1302, AP 125(1) registers
with CTF 135. At operation 1304, access VXLAN tunnel AT0 is
established between AP 125(1) and switch 155(1). At operation 1306,
AP 125(2) registers with CTF 135. At operation 1308, access VXLAN
tunnel AT1 is established between AP 125(2) and switch 155(1). At
operation 1310, AP 125(3) registers with CTF 135. At operation
1312, access VXLAN tunnel AT2 is established between AP 125(3) and
switch 155(1).
[0128] At operation 1314, UE 105 enters active mode. At operation
1316, AP 125(1) obtains the default bearer for UE 105. At operation
1318, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 1320, CTF 135 obtains the default bearer for UE 105. At
operation 1322, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0129] At operation 1324, AP 125(1) obtains an RRC measurement
report from UE 105. At operation 1326, AP 125(1) determines that a
handover needs to be performed, selects the target cell (e.g.,
selects AP 125(3) as the target AP), and derives KeNB* (in the 4G
case). At operation 1328, CTF 135 obtains a notification that a
handover is to occur for UE 105 from AP 125(1) to AP 125(3). The
notification may include, for example, an identification of AP
125(3), the target TAI for AP 125(3) (e.g., identifying tracking
area 110), and a Source to Target Transparent Container.
[0130] At operation 1330, CTF 135 provides, to AP 125(3), an
indication to decapsulate encapsulated downlink packets destined
for UE 105. The encapsulated downlink packets destined for UE 105
are encapsulated with an outer header (e.g., a VXLAN header)
identifying AP 125(1) as a source of the encapsulated downlink
packets and further identifying AP 125(3) as a destination of the
encapsulated downlink packets. The indication may comprise a
handover request including the Source to Target Transparent
Container, and may further include an identification of AP
125(1).
[0131] At operation 1332, AP 125(3) generates AS keys from KeNB*
and allocates a C-RNTI for UE 105. At operation 1334, CTF 135
obtains a handover request acknowledgement from AP 125(3). At
operation 1336, AP 125(3) locally creates a VXLAN tunnel between AP
125(1) and AP 125(3). AP 125(3) is now configured to buffer
downlink packets destined for UE 105 obtained from AP 125(1) via
the VXLAN tunnel. At operation 1338, CTF 135 may prepare a GTP
Create Indirect Data Forwarding Tunnel Request, although this may
not be required.
[0132] At operation 1340, CTF 135 provides, to AP 125(1), an
indication to replicate downlink packets destined UE 105 to
generate a first copy of the downlink packets and a second copy of
the downlink packets, and encapsulate the first copy of the
downlink packets with the outer header to generate the encapsulated
downlink packets. The indication may comprise a handover command.
At 1342, AP 125(1) locally creates the VXLAN tunnel between AP
125(1) and AP 125(3). AP 125(1) is now configured to provide
downlink packets destined for UE 105 to AP 125(3) via the VXLAN
tunnel. Thus, the VXLAN tunnel between AP 125(1) and AP 125(3) is
now established.
[0133] FIG. 14 illustrates a call flow diagram of an example method
1400 of handover execution utilizing the third mechanism in
handover scenario 170(2). Initially, border node 165 may obtain
downlink packets from DN 120. The downlink packets may be destined
for UE 105 (e.g., the downlink packets may identify the MAC or IP
address of UE 105 as the destination addresses of the downlink
packets). At operation 1402, border node 165 provides the downlink
packets to switch 155(1). At operation 1404, switch 155(1) provides
the downlink packets destined for UE 105 to AP 125(1).
[0134] At operation 1406, AP 125(1) replicates the downlink packets
destined for UE 105 to generate the first copy of the downlink
packets and the second copy of the downlink packets, encapsulates
the first copy of the downlink packets with the outer header to
generate the encapsulated downlink packets, and provides the
encapsulated downlink packets to switch 155(1). AP 125(1) may
provide the encapsulated downlink packets to switch 155(1) over the
VXLAN tunnel. At operation 1408, AP 125(1) provides the second copy
of the downlink packets to UE 105.
[0135] Because method 1400 involves handover scenario 170(2), the
tunnel router associated with AP 125(1) (i.e., switch 155(1) is
different from the tunnel router associated with AP 125(3) (i.e.,
switch 155(2)). Accordingly, at operation 1410, switch 155(1)
identifies AP 125(3) as the destination of the encapsulated
downlink packets based on the outer header, which identifies AP
125(1) as the source of the encapsulated downlink packets and AP
125(3) as the destination of the encapsulated downlink packet.
Switch 155(1) further provides the encapsulated downlink packets to
switch 155(2). At operation 1412, switch 155(2) identifies AP
125(3) as the destination of the encapsulated downlink packets
based on the outer header and provides the encapsulated downlink
packets to AP 125(3). AP 125(3) decapsulates the encapsulated
downlink packets and, at operation 1413, buffers the first copy of
the downlink packets until AP 125(3) obtains a handover
confirmation from UE 105. AP 125(3) may decapsulate the
encapsulated downlink packets in response to determining that the
outer header identifies AP 125(1) as the source of the encapsulated
downlink packets, and based further on a previously obtained
identification of AP 125(1) as the source AP from which UE 105 is
transitioning (e.g., at operation 1330).
[0136] At operation 1414, AP 125(1) provides an RRC Connection
Reconfiguration Request to UE 105. At operation 1416, CTF 135
obtains an AP status transfer from AP 125(1). At operation 1418, AP
125(3) obtains, from UE 105, an indication that the RRC connection
reconfiguration is complete. The indication may include the target
C-RNTI. At operation 1420, AP 125(3) obtains the handover
confirmation from UE 105, and the handover procedure is complete.
At this point, AP 125(3) is configured to forward the buffered
downlink packets to UE 105 and obtain uplink packets from UE
105.
[0137] At operation 1422, AP 125(3) provides the buffered downlink
packets to UE 105. Thus, UE 105 obtains downlink packets from both
AP 125(1) and AP 125(3) during the handover procedure to help
ensure that no downlink packets are lost. If UE 105 obtains
identical copies of a given downlink packet, UE 105 may simply drop
one of the identical copies. At operation 1424, AP 125(3) obtains
uplink packets from UE 105. The uplink packets may be destined for
DN 120. At operation 1426, switch 155(2) may obtain the uplink
packets from AP 125(3). At operation 1428, switch 155(2) may
provide the uplink packets to border node 165, which may in turn
provide the uplink packets to DN 120.
[0138] At operation 1430, CTF 135 obtains a notification that the
handover has occurred from AP 125(3) and that AP 125(3) has stopped
or will stop decapsulating encapsulated downlink packets destined
for UE 105. At operation 1432, AP 125(3) locally deletes the VXLAN
tunnel between AP 125(1) and AP 125(3). At operation 1434, CTF 135
starts a handover release timer. At operation 1436, CTF 135
provides a registration message (instead of a modify bearer
request) to MS 140. The registration message includes a mapping of
the EID of UE 105 to the RLOC of switch 155(2). The registration
message further includes an indication that the RLOC of switch
155(2) is associated with AP 125(3). In one specific example, the
registration message may include a L2 VNID, an EID set to the MAC
address of UE 105, an RLOC set to the RLOC of switch 155(2), and a
TLV identifying the IP address of AP 125(3) and the appropriate
SGT.
[0139] At operation 1438, based on the registration message, MS 140
provides, to switch 155(2), a notification message including the
mapping of the EID of UE 105 to the RLOC of switch 155(2) and an
indication for switch 155(2) to provide downlink packets destined
for UE 105 to AP 125(3). In one specific example, MS 140 provides,
to switch 155(2), a proxy notify message including the L2 VNID, the
EID set to the MAC address of UE 105, the RLOC set to the RLOC of
switch 155(2), and the TLV identifying the IP address of AP 125(3)
and the appropriate SGT. At operation 1440, based on the
notification message, switch 155(2) maps the MAC address of UE 105
to AT2. This causes switch 155(2) to forward downlink packets
destined for UE 105 to AP 125(3).
[0140] At operations 1442 and 1444, MS 140 provides publications to
switch 155(1) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(2). At operation 1446, switch 155(2)
obtains, from border node 165, downlink packets destined for UE
105. At operation 1448, based on the notification message, switch
155(2) provides, to AP 125(3), the downlink packets destined for UE
105. At operation 1450, AP 125(3) provides the downlink packets to
UE 105. At operation 1452, CTF 135 determines that the handover
release timer has expired.
[0141] At operation 1454, in response to the handover release timer
expiring, CTF 135 provides, to AP 125(1), an indication to stop
replicating the downlink packets destined UE 105 and encapsulating
the downlink packets with the outer header to generate the
encapsulated downlink packets. The indication may comprise a UE
context release command. At operation 1456, CTF 135 obtains a UE
context release complete message from AP 125(1). At operation 1458,
AP 125(1) locally deletes the VXLAN tunnel between AP 125(1) and AP
125(3). Thus, the VXLAN tunnel between AP 125(1) and AP 125(3) is
now removed, and AP 125(1) stops replicating the downlink packets
destined UE 105 and encapsulating the downlink packets with the
outer header to generate the encapsulated downlink packets.
[0142] Unlike FIGS. 2-14, which relate to downlink packet
replication to support an S1AP handover, FIGS. 15A, 15B, 16A, and
16B relate to downlink packet replication to support an X2
handover. In particular, and with continued reference to FIG. 1,
FIGS. 15A and 15B relate to handover scenario 170(1), and FIGS. 16A
and 16B relate to handover scenario 170(2).
[0143] Turning first to FIGS. 15A and 15B, shown is a call flow
diagram of an example method 1500 for replicating downlink packets
on a source AP in handover scenario 170(1). At operation 1502, AP
125(1) registers with CTF 135. At operation 1504, access VXLAN
tunnel AT0 is established between AP 125(1) and switch 155(1). At
operation 1506, AP 125(2) registers with CTF 135. At operation
1508, access VXLAN tunnel AT1 is established between AP 125(2) and
switch 155(1). At operation 1510, AP 125(3) registers with CTF 135.
At operation 1512, access VXLAN tunnel AT2 is established between
AP 125(3) and switch 155(1).
[0144] At operation 1514, UE 105 enters active mode. At operation
1516, AP 125(1) obtains the default bearer for UE 105. At operation
1518, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 1520, CTF 135 obtains the default bearer for UE 105. At
operation 1522, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0145] At operation 1524, AP 125(1) obtains an RRC measurement
report from UE 105. At operation 1526, AP 125(1) provides a
handover request to AP 125(2). At operation 1528, AP 125(2)
provides a handover request acknowledgment to AP 125(1). At
operation 1530, AP 125(1) provides a handover command to UE 105. At
operation 1532, AP 125(1) provides a Sequence Number (SN) transfer
status to AP 125(2). At operation 1534, switch 155(1) obtains
downlink packets destined for UE 105 from border node 165. Border
node 165 may have obtained the downlink packets from DN 120. The
downlink packets may, for example, identify the MAC or IP address
of UE 105 as the destination addresses of the downlink packets. At
operation 1535, AP 125(1) obtains the downlink packets from switch
155(1). At operation 1536, AP 125(1) replicates the downlink
packets to generate a first copy of the downlink packets and a
second copy of the downlink packets and provides the first copy of
the downlink packets to AP 125(2). At operation 1538, AP 125(1)
provides the second copy of the downlink packets to UE 105. At
operation 1540, AP 125(2) buffers the first copy of the downlink
packets until AP 125(2) obtains a handover confirmation from UE
105.
[0146] At operation 1542, AP 125(2) obtains the handover
confirmation from UE 105, and a data plane is thereby established
between UE 105 and AP 125(2). At operation 1544, AP 125(2) provides
the first copy of the downlink packets to UE 105. Thus, UE 105
obtains downlink packets from both AP 125(1) and AP 125(2) during
the handover procedure to help ensure that no downlink packets are
lost. If UE 105 obtains identical copies of a given downlink
packet, UE 105 may simply drop one of the identical copies. At
operation 1546, AP 125(2) obtains uplink packets from UE 105. The
uplink packets may be destined for DN 120. At operation 1548,
switch 155(1) may obtain the uplink packets from AP 125(2). At
operation 1550, switch 155(1) may provide the uplink packets to
border node 165, which may in turn provide the uplink packets to DN
120.
[0147] At operation 1552, CTF 135 may obtain, from AP 125(2), a
path switch request including the IP address of UE 105 and the
corresponding Tunnel Endpoint ID (TEID). At operation 1554, CTF 135
provides a registration message (instead of a modify bearer
request) to MS 140. The registration message includes a mapping of
the EID of UE 105 to the RLOC of switch 155(1). The registration
message further includes an indication that the RLOC of switch
155(1) is associated with AP 125(2). In one specific example, the
registration message may include a L2 VNID, an EID set to the MAC
address of UE 105, an RLOC set to the RLOC of switch 155(1), and a
TLV identifying the IP address of AP 125(2).
[0148] At operation 1556, based on the registration message, MS 140
provides, to switch 155(1), a notification message including the
mapping of the EID of UE 105 to the RLOC of switch 155(1) and an
indication for switch 155(1) to provide downlink packets destined
for UE 105 to AP 125(2). In one specific example, MS 140 provides,
to switch 155(1), a proxy notify message including the L2 VNID, the
EID set to the MAC address of UE 105, the RLOC set to the RLOC of
switch 155(1), and the TLV identifying the IP address of AP 125(2).
At operation 1558, based on the notification message, switch 155(1)
maps the MAC address of UE 105 to AT1. This causes switch 155(1) to
forward downlink packets destined for UE 105 to AP 125(2).
[0149] At operations 1560 and 1562, MS 140 provides publications to
switch 155(2) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(1). At operation 1564, CTF 135 provides,
to AP 125(2), a path switch acknowledgment including the IP address
of UE 105 and the corresponding TEID. At operation 1566, switch
155(1) obtains, from border node 165, downlink packets destined for
UE 105. At operation 1568, switch 155(1) provides, to AP 125(2),
the downlink packets destined for UE 105. At operation 1570, AP
125(2) provides the downlink packets to UE 105. At operation 1572,
AP 125(2) provides a UE context release to AP 125(1).
[0150] FIGS. 16A and 16B collectively illustrate a call flow
diagram of an example method 1600 for replicating downlink packets
on a source AP in handover scenario 170(2). At operation 1602, AP
125(1) registers with CTF 135. At operation 1604, access VXLAN
tunnel AT0 is established between AP 125(1) and switch 155(1). At
operation 1606, AP 125(2) registers with CTF 135. At operation
1608, access VXLAN tunnel AT1 is established between AP 125(2) and
switch 155(1). At operation 1610, AP 125(3) registers with CTF 135.
At operation 1612, access VXLAN tunnel AT2 is established between
AP 125(3) and switch 155(1).
[0151] At operation 1614, UE 105 enters active mode. At operation
1616, AP 125(1) obtains the default bearer for UE 105. At operation
1618, switch 155(1) maps the MAC address of UE 105 to AT0. This
causes switch 155(1) to forward downlink packets with a destination
address set to the MAC address of UE 105, over AT0 to AP 125(1). At
operation 1620, CTF 135 obtains the default bearer for UE 105. At
operation 1622, MS 140 stores the EID of UE 105 (e.g., the MAC
address of UE 105, the IP address of UE 105, etc.) and sets the
corresponding RLOC to the RLOC of switch 155(1) and the
corresponding AP IP address to the IP address of AP 125(1). For
example, MS 140 may provide, to switches 155(1) and 155(2) and
border node 165, a notification message including a mapping of the
EID of UE 105 to the RLOC of switch 155(1) and a TLV indicating
that the corresponding AP IP address is the IP address of AP
125(1). Thus, initially, border node 165 is configured to provide
downlink packets destined for UE 105 to switch 155(1), which is
configured to provide the downlink packets to AP 125(1), which is
in turn configured to provide the downlink packets to UE 105.
[0152] At operation 1624, AP 125(1) obtains an RRC measurement
report from UE 105. At operation 1626, AP 125(1) provides a
handover request to AP 125(3). At operation 1628, AP 125(3)
provides a handover request acknowledgment to AP 125(1). At
operation 1630, AP 125(1) provides a handover command to UE 105. At
operation 1632, AP 125(1) provides an SN transfer status to AP
125(3). At operation 1634, switch 155(1) obtains downlink packets
destined for UE 105 from border node 165. Border node 165 may have
obtained the downlink packets from DN 120. The downlink packets
may, for example, identify the MAC or IP address of UE 105 as the
destination addresses of the downlink packets. At operation 1635,
AP 125(1) obtains the downlink packets from switch 155(1). At
operation 1636, AP 125(1) replicates the downlink packets to
generate a first copy of the downlink packets and a second copy of
the downlink packets and provides the first copy of the downlink
packets to AP 125(3). At operation 1638, AP 125(1) provides the
second copy of the downlink packets to UE 105. At operation 1640,
AP 125(3) buffers the first copy of the downlink packets until AP
125(3) obtains a handover confirmation from UE 105.
[0153] At operation 1642, AP 125(3) obtains the handover
confirmation from UE 105, and a data plane is thereby established
between UE 105 and AP 125(3). At operation 1644, AP 125(3) provides
the first copy of the downlink packets to UE 105. Thus, UE 105
obtains downlink packets from both AP 125(1) and AP 125(3) during
the handover procedure to help ensure that no downlink packets are
lost. If UE 105 obtains identical copies of a given downlink
packet, UE 105 may simply drop one of the identical copies. At
operation 1646, AP 125(3) obtains uplink packets from UE 105. The
uplink packets may be destined for DN 120. At operation 1648,
switch 155(2) may obtain the uplink packets from AP 125(3). At
operation 1650, switch 155(2) may provide the uplink packets to
border node 165, which may in turn provide the uplink packets to DN
120.
[0154] At operation 1652, CTF 135 may obtain, from AP 125(3), a
path switch request including the IP address of UE 105 and the
corresponding TEID. At operation 1654, CTF 135 provides a
registration message (instead of a modify bearer request) to MS
140. The registration message includes a mapping of the EID of UE
105 to the RLOC of switch 155(2). The registration message further
includes an indication that the RLOC of switch 155(2) is associated
with AP 125(3). In one specific example, the registration message
may include a L2 VNID, an EID set to the MAC address of UE 105, an
RLOC set to the RLOC of switch 155(2), and a TLV identifying the IP
address of AP 125(3).
[0155] At operation 1656, based on the registration message, MS 140
provides, to switch 155(2), a notification message including the
mapping of the EID of UE 105 to the RLOC of switch 155(2) and an
indication for switch 155(2) to provide downlink packets destined
for UE 105 to AP 125(3). In one specific example, MS 140 provides,
to switch 155(2), a proxy notify message including the L2 VNID, the
EID set to the MAC address of UE 105, the RLOC set to the RLOC of
switch 155(2), and the TLV identifying the IP address of AP 125(3).
At operation 1658, based on the notification message, switch 155(2)
maps the MAC address of UE 105 to AT2. This causes switch 155(2) to
forward downlink packets destined for UE 105 to AP 125(3).
[0156] At operations 1660 and 1662, MS 140 provides publications to
switch 155(1) and border node 165, respectively. The publications
include the L2 VNID for the MAC address of UE 105 and the RLOC set
to the RLOC of switch 155(2). At operation 1664, switch 155(1)
deletes the mapping of the MAC address of UE 105 to AT0. At
operation 1666, CTF 135 provides, to AP 125(3), a path switch
acknowledgment including the IP address of UE 105 and the
corresponding TEID. At operation 1668, switch 155(2) obtains, from
border node 165, downlink packets destined for UE 105. At operation
1670, switch 155(2) provides, to AP 125(3), the downlink packets
destined for UE 105. At operation 1672, AP 125(3) provides the
downlink packets to UE 105. At operation 1674, AP 125(3) provides a
UE context release to AP 125(1).
[0157] FIG. 17 illustrates a hardware block diagram of an example
device 1700 (e.g., CTF 135). It should be appreciated that FIG. 17
provides only an illustration of one embodiment and does not imply
any limitations with regard to the environments in which different
embodiments may be implemented. Many modifications to the depicted
environment may be made.
[0158] As depicted, the device 1700 includes a bus 1712, which
provides communications between computer processor(s) 1714, memory
1716, persistent storage 1718, communications unit 1720, and
Input/Output (1/O) interface(s) 1722. Bus 1712 can be implemented
with any architecture designed for passing data and/or control
information between processors (such as microprocessors,
communications and network processors, etc.), system memory,
peripheral devices, and any other hardware components within a
system. For example, bus 1712 can be implemented with one or more
buses.
[0159] Memory 1716 and persistent storage 1718 are computer
readable storage media. In the depicted embodiment, memory 1716
includes Random Access Memory (RAM) 1724 and cache memory 1726. In
general, memory 1716 can include any suitable volatile or
non-volatile computer readable storage media. Instructions for
handover support logic 175 may be stored in memory 1716 or
persistent storage 1718 for execution by computer processor(s)
1714.
[0160] One or more programs may be stored in persistent storage
1718 for execution by one or more of the respective computer
processors 1714 via one or more memories of memory 1716. The
persistent storage 1718 may be a magnetic hard disk drive, a solid
state hard drive, a semiconductor storage device, Read-Only Memory
(ROM), Erasable Programmable ROM (EPROM), Flash memory, or any
other computer readable storage media that is capable of storing
program instructions or digital information.
[0161] The media used by persistent storage 1718 may also be
removable. For example, a removable hard drive may be used for
persistent storage 1718. Other examples include optical and
magnetic disks, thumb drives, and smart cards that are inserted
into a drive for transfer onto another computer readable storage
medium that is also part of persistent storage 1718.
[0162] Communications unit 1720, in these examples, provides for
communications with other data processing systems or devices. In
these examples, communications unit 1720 includes one or more
network interface cards. Communications unit 1720 may provide
communications through the use of either or both physical and
wireless communications links.
[0163] I/O interface(s) 1722 allows for input and output of data
with other devices that may be connected to device 1700. For
example, I/O interface(s) 1722 may provide a connection to external
devices 1728 such as a keyboard, keypad, a touch screen, and/or
some other suitable input device. External devices 1728 can also
include portable computer readable storage media such as database
systems, thumb drives, portable optical or magnetic disks, and
memory cards.
[0164] Software and data used to practice embodiments can be stored
on such portable computer readable storage media and can be loaded
onto persistent storage 1718 via I/O interface(s) 1722. I/O
interface(s) 1722 may also connect to a display 1730. Display 1730
provides a mechanism to display data to a user and may be, for
example, a computer monitor.
[0165] FIG. 18 illustrates a flowchart of an example method 1800
for downlink packet replication on a fabric node or on a source AP
using a target access point as a secondary AP in an S1AP handover
scenario. Method 1800 may be performed by CTF 135. At operation
1810, CTF 135 obtains a notification that a handover is to occur
for a UE from a source AP to a target AP. At operation 1820, CTF
135 identifies a RLOC for a tunnel router associated with the
source AP and a RLOC for a tunnel router associated with the target
AP. At operation 1830, CTF 135 provides, to a MS, a registration
message including a mapping of an endpoint identifier of the UE to
the RLOC for the tunnel router associated with the source AP and
the RLOC for the tunnel router associated with the target AP. Based
on the registration message, the MS causes downlink packets
destined for the UE to be replicated and provided to the source AP
and to the target AP.
[0166] FIG. 19 illustrates a flowchart of an example method 1900
for downlink packet replication on a source AP using packet
encapsulation in an S1AP handover scenario. Method 1900 may be
performed by CTF 135. At operation 1910, CTF 135 obtains a
notification that a handover is to occur for a UE from a source AP
to a target AP. At operation 1920, CTF 135 provides, to the target
AP, an indication to decapsulate encapsulated downlink packets
destined for the UE. The encapsulated downlink packets destined for
the UE are encapsulated with an outer header identifying the source
AP as a source of the encapsulated downlink packets destined for
the UE and further identifying the target AP as a destination of
the encapsulated downlink packets destined for the UE. At operation
1930, CTF 135 provides, to the source AP, an indication to
replicate downlink packets destined for the UE to generate a first
copy of the downlink packets destined for the UE and a second copy
of the downlink packets destined for the UE, and encapsulate the
first copy of the downlink packets destined for the UE with the
outer header to generate the encapsulated downlink packets destined
for the UE.
[0167] The techniques described herein may utilize MS mobility
scalability capabilities, and may be applied to any suitable
cellular technology (e.g., 4G, 5G, etc.). For example, while
certain embodiments described herein relate to 4G technology, it
will be appreciated that these techniques may also be applicable to
5G technology. In particular, the descriptions provided herein for
the handover procedures in the 4G case may be functionally similar
to analogous handover procedures in the 5G case. For example, the
5G case may utilize a gNB instead of an eNB, an N2 handover instead
of an S1AP handover, and an Xn handover instead of an X2 handover.
Other telecommunication capabilities, such as Wi-Fi.RTM., may also
be incorporated. Various embodiments may be envisioned.
[0168] The programs described herein are identified based upon the
application for which they are implemented in a specific
embodiment. However, it should be appreciated that any particular
program nomenclature herein is used merely for convenience, and
thus the embodiments should not be limited to use solely in any
specific application identified and/or implied by such
nomenclature.
[0169] Data relating to operations described herein may be stored
within any conventional or other data structures (e.g., files,
arrays, lists, stacks, queues, records, etc.) and may be stored in
any desired storage unit (e.g., database, data or other
repositories, queue, etc.). The data transmitted between entities
may include any desired format and arrangement, and may include any
quantity of any types of fields of any size to store the data. The
definition and data model for any datasets may indicate the overall
structure in any desired fashion (e.g., computer-related languages,
graphical representation, listing, etc.).
[0170] The present embodiments may employ any number of any type of
user interface (e.g., Graphical User Interface (GUI), command-line,
prompt, etc.) for obtaining or providing information, where the
interface may include any information arranged in any fashion. The
interface may include any number of any types of input or actuation
mechanisms (e.g., buttons, icons, fields, boxes, links, etc.)
disposed at any locations to enter/display information and initiate
desired actions via any suitable input devices (e.g., mouse,
keyboard, etc.). The interface screens may include any suitable
actuators (e.g., links, tabs, etc.) to navigate between the screens
in any fashion.
[0171] The environment of the present embodiments may include any
number of computer or other processing systems (e.g., client or
end-user systems, server systems, etc.) and databases or other
repositories arranged in any desired fashion, where the present
embodiments may be applied to any desired type of computing
environment (e.g., cloud computing, client-server, network
computing, mainframe, stand-alone systems, etc.). The computer or
other processing systems employed by the present embodiments may be
implemented by any number of any personal or other type of computer
or processing system (e.g., desktop, laptop, Personal Digital
Assistant (PDA), mobile devices, etc.), and may include any
commercially available operating system and any combination of
commercially available and custom software (e.g., machine learning
software, etc.). These systems may include any types of monitors
and input devices (e.g., keyboard, mouse, voice recognition, etc.)
to enter and/or view information.
[0172] It is to be understood that the software of the present
embodiments may be implemented in any desired computer language and
could be developed by one of ordinary skill in the computer arts
based on the functional descriptions contained in the specification
and flow charts illustrated in the drawings. Further, any
references herein of software performing various functions
generally refer to computer systems or processors performing those
functions under software control. The computer systems of the
present embodiments may alternatively be implemented by any type of
hardware and/or other processing circuitry.
[0173] The various functions of the computer or other processing
systems may be distributed in any manner among any number of
software and/or hardware modules or units, processing or computer
systems and/or circuitry, where the computer or processing systems
may be disposed locally or remotely of each other and communicate
via any suitable communications medium (e.g., Local Area Network
(LAN), Wide Area Network (WAN), Intranet, Internet, hardwire, modem
connection, wireless, etc.). For example, the functions of the
present embodiments may be distributed in any manner among the
various end-user/client and server systems, and/or any other
intermediary processing devices. The software and/or algorithms
described above and illustrated in the flow charts may be modified
in any manner that accomplishes the functions described herein. In
addition, the functions in the flow charts or description may be
performed in any order that accomplishes a desired operation.
[0174] The software of the present embodiments may be available on
a non-transitory computer useable medium (e.g., magnetic or optical
mediums, magneto-optic mediums, floppy diskettes, Compact Disc ROM
(CD-ROM), Digital Versatile Disk (DVD), memory devices, etc.) of a
stationary or portable program product apparatus or device for use
with stand-alone systems or systems connected by a network or other
communications medium.
[0175] The communication network may be implemented by any number
of any type of communications network (e.g., LAN, WAN, Internet,
Intranet, Virtual Private Network (VPN), etc.). The computer or
other processing systems of the present embodiments may include any
conventional or other communications devices to communicate over
the network via any conventional or other protocols. The computer
or other processing systems may utilize any type of connection
(e.g., wired, wireless, etc.) for access to the network. Local
communication media may be implemented by any suitable
communication media (e.g., LAN, hardwire, wireless link, Intranet,
etc.).
[0176] Each of the elements described herein may couple to and/or
interact with one another through interfaces and/or through any
other suitable connection (wired or wireless) that provides a
viable pathway for communications. Interconnections, interfaces,
and variations thereof discussed herein may be utilized to provide
connections among elements in a system and/or may be utilized to
provide communications, interactions, operations, etc. among
elements that may be directly or indirectly connected in the
system. Any combination of interfaces can be provided for elements
described herein in order to facilitate operations as discussed for
various embodiments described herein.
[0177] The system may employ any number of any conventional or
other databases, data stores or storage structures (e.g., files,
databases, data structures, data or other repositories, etc.) to
store information. The database system may be implemented by any
number of any conventional or other databases, data stores or
storage structures to store information. The database system may be
included within or coupled to the server and/or client systems. The
database systems and/or storage structures may be remote from or
local to the computer or other processing systems, and may store
any desired data.
[0178] The embodiments presented may be in various forms, such as a
system, a method, and/or a computer program product at any possible
technical detail level of integration. The computer program product
may include a computer readable storage medium (or media) having
computer readable program instructions thereon for causing a
processor to carry out aspects presented herein.
[0179] The computer readable storage medium can be a tangible
device that can retain and store instructions for use by an
instruction execution device. The computer readable storage medium
may be, for example, but is not limited to, an electronic storage
device, a magnetic storage device, an optical storage device, an
electromagnetic storage device, a semiconductor storage device, or
any suitable combination of the foregoing. A non-exhaustive list of
more specific examples of the computer readable storage medium
includes the following: a portable computer diskette, a hard disk,
a RAM, a ROM, EPROM, Flash memory, a Static RAM (SRAM), a portable
CD-ROM, a DVD, a memory stick, a floppy disk, a mechanically
encoded device, and any suitable combination of the foregoing. A
computer readable storage medium, as used herein, is not to be
construed as being transitory signals per se, such as radio waves
or other freely propagating electromagnetic waves, electromagnetic
waves propagating through a waveguide or other transmission media
(e.g., light pulses passing through a fiber-optic cable), or
electrical signals transmitted through a wire.
[0180] Computer readable program instructions described herein can
be downloaded to respective computing/processing devices from a
computer readable storage medium or to an external computer or
external storage device via a network, for example, the Internet, a
LAN, a WAN, and/or a wireless network. The network may comprise
copper transmission cables, optical transmission fibers, wireless
transmission, routers, firewalls, switches, gateway computers
and/or edge servers. A network adapter card or network interface in
each computing/processing device receives computer readable program
instructions from the network and forwards the computer readable
program instructions for storage in a computer readable storage
medium within the respective computing/processing device.
[0181] Computer readable program instructions for carrying out
operations of the present embodiments may be assembler
instructions, Instruction-Set-Architecture (ISA) instructions,
machine instructions, machine dependent instructions, microcode,
firmware instructions, state-setting data, configuration data for
integrated circuitry, or either source code or object code written
in any combination of one or more programming languages, including
an object oriented programming language such as Python, C++, or the
like, and procedural programming languages, such as the "C"
programming language or similar programming languages. The computer
readable program instructions may execute entirely on the user's
computer, partly on the user's computer, as a stand-alone software
package, partly on the user's computer and partly on a remote
computer or entirely on the remote computer or server. In the
latter scenario, the remote computer may be connected to the user's
computer through any type of network, including a LAN or a WAN, or
the connection may be made to an external computer (for example,
through the Internet using an Internet Service Provider). In some
embodiments, electronic circuitry including, for example,
programmable logic circuitry, Field-Programmable Gate Arrays
(FPGA), or Programmable Logic Arrays (PLA) may execute the computer
readable program instructions by utilizing state information of the
computer readable program instructions to personalize the
electronic circuitry, in order to perform aspects presented
herein.
[0182] Aspects of the present embodiments are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatus (systems), and computer program products
according to the embodiments. It will be understood that each block
of the flowchart illustrations and/or block diagrams, and
combinations of blocks in the flowchart illustrations and/or block
diagrams, can be implemented by computer readable program
instructions.
[0183] These computer readable program instructions may be provided
to a processor of a general purpose computer, special purpose
computer, or other programmable data processing apparatus to
produce a machine, such that the instructions, which execute via
the processor of the computer or other programmable data processing
apparatus, create means for implementing the functions/acts
specified in the flowchart and/or block diagram block or blocks.
These computer readable program instructions may also be stored in
a computer readable storage medium that can direct a computer, a
programmable data processing apparatus, and/or other devices to
function in a particular manner, such that the computer readable
storage medium having instructions stored therein comprises an
article of manufacture including instructions which implement
aspects of the function/act specified in the flowchart and/or block
diagram block or blocks.
[0184] The computer readable program instructions may also be
loaded onto a computer, other programmable data processing
apparatus, or other device to cause a series of operational steps
to be performed on the computer, other programmable apparatus or
other device to produce a computer implemented process, such that
the instructions which execute on the computer, other programmable
apparatus, or other device implement the functions/acts specified
in the flowchart and/or block diagram block or blocks.
[0185] The flowchart and block diagrams in the figures illustrate
the architecture, functionality, and operation of possible
implementations of systems, methods, and computer program products
according to various embodiments. In this regard, each block in the
flowchart or block diagrams may represent a module, segment, or
portion of instructions, which comprises one or more executable
instructions for implementing the specified logical function(s). In
some alternative implementations, the functions noted in the blocks
may occur out of the order noted in the figures. For example, two
blocks shown in succession may, in fact, be executed substantially
concurrently, or the blocks may sometimes be executed in the
reverse order, depending upon the functionality involved. It will
also be noted that each block of the block diagrams and/or
flowchart illustration, and combinations of blocks in the block
diagrams and/or flowchart illustration, can be implemented by
special purpose hardware-based systems that perform the specified
functions or acts or carry out combinations of special purpose
hardware and computer instructions.
[0186] The descriptions of the various embodiments have been
presented for purposes of illustration, but are not intended to be
exhaustive or limited to the embodiments disclosed. Many
modifications and variations will be apparent to those of ordinary
skill in the art without departing from the scope and spirit of the
described embodiments. The terminology used herein was chosen to
best explain the principles of the embodiments, the practical
application or technical improvement over technologies found in the
marketplace, or to enable others of ordinary skill in the art to
understand the embodiments disclosed herein.
[0187] In one form, a method is provided. The method comprises:
obtaining a notification that a handover is to occur for a user
equipment from a source access point to a target access point;
identifying a routing locator for a tunnel router associated with
the source access point and a routing locator for a tunnel router
associated with the target access point; and providing, to a map
server, a registration message including a mapping of an endpoint
identifier of the user equipment to the routing locator for the
tunnel router associated with the source access point and the
routing locator for the tunnel router associated with the target
access point, wherein based on the registration message, the map
server causes downlink packets destined for the user equipment to
be replicated and provided to the source access point and to the
target access point.
[0188] In one example, the tunnel router associated with the source
access point and the tunnel router associated with the target
access point are a single tunnel router, identifying includes
identifying a single routing locator for the single tunnel router,
and providing includes providing a registration message including a
mapping of the endpoint identifier of the user equipment to the
single routing locator.
[0189] In a further example, providing includes providing a
registration message including an indication for the single tunnel
router to replicate the downlink packets destined for the user
equipment to generate a first copy of the downlink packets destined
for the user equipment and a second copy of the downlink packets
destined for the user equipment, provide the first copy of the
downlink packets destined for the user equipment to the source
access point, and provide the second copy of the downlink packets
destined for the user equipment to the target access point; based
on the registration message, the map server provides, to the single
tunnel router, a notification message including the mapping of the
endpoint identifier of the user equipment to the single routing
locator and the indication; and based on the notification message,
the single tunnel router replicates the downlink packets destined
for the user equipment to generate the first copy of the downlink
packets destined for the user equipment and the second copy of the
downlink packets destined for the user equipment, provides the
first copy of the downlink packets destined for the user equipment
to the source access point, and provides the second copy of the
downlink packets destined for the user equipment to the target
access point.
[0190] In another further example, providing includes providing a
registration message including an indication that the target access
point is a secondary access point to which the single tunnel router
is to provide any of the downlink packets destined for the user
equipment that are obtained from the source access point; based on
the registration message, the map server provides, to the single
tunnel router, a notification message including the mapping of the
endpoint identifier of the user equipment to the single routing
locator and the indication that the target access point is the
secondary access point; the single tunnel router provides the
downlink packets destined for the user equipment to the source
access point; the source access point replicates the downlink
packets destined for the user equipment to generate a first copy of
the downlink packets destined for the user equipment and a second
copy of the downlink packets destined for the user equipment, and
provides the first copy of the downlink packets destined for the
user equipment to the single tunnel router; and based on the
notification message, the single tunnel router provides the first
copy of the downlink packets destined for the user equipment to the
target access point.
[0191] In still another further example, the method further
comprises: obtaining a notification that the handover has occurred;
and providing, to the map server, another registration message
including the mapping of the endpoint identifier of the user
equipment to the single routing locator, the other registration
message including an indication that the single routing locator is
associated with the target access point, wherein based on the other
registration message, the map server provides, to the single tunnel
router, a notification message including the mapping of the
endpoint identifier of the user equipment to the single routing
locator and an indication to provide the downlink packets destined
for the user equipment to the target access point, and based on the
notification message, the single tunnel router provides the
downlink packets destined for the user equipment to the target
access point.
[0192] In one example, the tunnel router associated with the source
access point is different from the tunnel router associated with
the target access point.
[0193] In a further example, providing includes providing a
registration message including an indication for a border node to
replicate the downlink packets destined for the user equipment to
generate a first copy of the downlink packets destined for the user
equipment and a second copy of the downlink packets destined for
the user equipment, provide the first copy of the downlink packets
destined for the user equipment to the tunnel router associated
with the source access point, and provide the second copy of the
downlink packets destined for the user equipment to the tunnel
router associated with the target access point; based on the
registration message, the map server provides, to the border node,
a publication including the mapping of the endpoint identifier of
the user equipment to the routing locator for the tunnel router
associated with the source access point and the routing locator for
the tunnel router associated with the target access point, and the
indication for a border node to replicate the downlink packets
destined for the user equipment to generate the first copy of the
downlink packets destined for the user equipment and the second
copy of the downlink packets destined for the user equipment,
provide the first copy of the downlink packets destined for the
user equipment to the tunnel router associated with the source
access point, and provide the second copy of the downlink packets
destined for the user equipment to the tunnel router associated
with the target access point; and based on the publication, the
border node replicates the downlink packets destined for the user
equipment to generate the first copy of the downlink packets
destined for the user equipment and the second copy of the downlink
packets destined for the user equipment, provides the first copy of
the downlink packets destined for the user equipment to the tunnel
router associated with the source access point, and provides the
second copy of the downlink packets destined for the user equipment
to the tunnel router associated with the target access point.
[0194] In a still further example, the method further comprises:
obtaining a notification that the handover has occurred; and
providing, to the map server, another registration message
including the mapping of the endpoint identifier of the user
equipment to the routing locator for the tunnel router associated
with the target access point, wherein based on the other
registration message, the map server provides, to the border node,
a publication including the mapping of the endpoint identifier of
the user equipment to the routing locator for the tunnel router
associated with the target access point, and an indication to
provide the downlink packets destined for the user equipment to the
tunnel router associated with the target access point, and based on
the publication, the border node provides the downlink packets
destined for the user equipment to the tunnel router associated
with the target access point.
[0195] In another further example, providing includes providing a
registration message including an indication that the target access
point is a secondary access point to which the tunnel router
associated with the source access point is to provide any of the
downlink packets destined for the user equipment that are obtained
from the source access point; based on the registration message,
the map server provides, to the tunnel router associated with the
source access point, a notification message including the mapping
of the endpoint identifier of the user equipment to the routing
locator for the tunnel router associated with the source access
point and the routing locator for the tunnel router associated with
the target access point, and the indication that the target access
point is the secondary access point; the tunnel router associated
with the source access point provides the downlink packets destined
for the user equipment to the source access point; the source
access point replicates the downlink packets destined for the user
equipment to generate a first copy of the downlink packets destined
for the user equipment and a second copy of the downlink packets
destined for the user equipment and provides the first copy of the
downlink packets destined for the user equipment to the tunnel
router associated with the source access point; based on the
notification message, the tunnel router associated with the source
access point provides the first copy of the downlink packets
destined for the user equipment to the tunnel router associated
with the target access point; and the tunnel router associated with
the target access point provides the first copy of the downlink
packets destined for the user equipment to the target access
point.
[0196] In another still further example, the method further
comprises: obtaining a notification that the handover has occurred;
and providing, to the map server, another registration message
including the mapping of the endpoint identifier of the user
equipment to the routing locator for the tunnel router associated
with the target access point, wherein based on the other
registration message, the map server provides, to the tunnel router
associated with the target access point, a notification message
including the mapping of the endpoint identifier of the user
equipment to the routing locator for the tunnel router associated
with the target access point, and an indication to provide the
downlink packets destined for the user equipment to the target
access point, and based on the notification message, the tunnel
router associated with the target access point provides the
downlink packets destined for the user equipment to the target
access point.
[0197] In one example, the source access point is a first fourth
generation evolved Node B and the target access point is a second
fourth generation evolved Node B; the source access point is a
first fifth generation next generation Node B and the target access
point is a second fifth generation next generation Node B; or the
source access point is a first citizens broadband radio service
device and the target access point is a second citizens broadband
radio service device.
[0198] In another form, an apparatus is provided. The apparatus
comprises: a network interface configured to obtain or provide
network communications; and one or more processors coupled to the
network interface, wherein the one or more processors are
configured to: obtain a notification that a handover is to occur
for a user equipment from a source access point to a target access
point; identify a routing locator for a tunnel router associated
with the source access point and a routing locator for a tunnel
router associated with the target access point; and provide, to a
map server, a registration message including a mapping of an
endpoint identifier of the user equipment to the routing locator
for the tunnel router associated with the source access point and
the routing locator for the tunnel router associated with the
target access point, wherein based on the registration message, the
map server causes downlink packets destined for the user equipment
to be replicated and provided to the source access point and to the
target access point.
[0199] In another form, one or more non-transitory computer
readable storage media are provided. The non-transitory computer
readable storage media are encoded with instructions that, when
executed by a processor, cause the processor to: obtain a
notification that a handover is to occur for a user equipment from
a source access point to a target access point; identify a routing
locator for a tunnel router associated with the source access point
and a routing locator for a tunnel router associated with the
target access point; and provide, to a map server, a registration
message including a mapping of an endpoint identifier of the user
equipment to the routing locator for the tunnel router associated
with the source access point and the routing locator for the tunnel
router associated with the target access point, wherein based on
the registration message, the map server causes downlink packets
destined for the user equipment to be replicated and provided to
the source access point and to the target access point.
[0200] In one form, another method is provided. The other method
comprises: obtaining a notification that a handover is to occur for
a user equipment from a source access point to a target access
point; providing, to the target access point, an indication to
decapsulate encapsulated downlink packets destined for the user
equipment, wherein the encapsulated downlink packets destined for
the user equipment are encapsulated with an outer header
identifying the source access point as a source of the encapsulated
downlink packets destined for the user equipment and further
identifying the target access point as a destination of the
encapsulated downlink packets destined for the user equipment; and
providing, to the source access point, an indication to replicate
downlink packets destined for the user equipment to generate a
first copy of the downlink packets destined for the user equipment
and a second copy of the downlink packets destined for the user
equipment, and encapsulate the first copy of the downlink packets
destined for the user equipment with the outer header to generate
the encapsulated downlink packets destined for the user
equipment.
[0201] In one example, the source access point and the target
access point are associated with a single tunnel router.
[0202] In a further example, the source access point replicates the
downlink packets destined for the user equipment to generate the
first copy of the downlink packets destined for the user equipment
and the second copy of the downlink packets destined for the user
equipment, encapsulates the first copy of the downlink packets
destined for the user equipment with the outer header to generate
the encapsulated downlink packets destined for the user equipment,
and provides the encapsulated downlink packets destined for the
user equipment to the single tunnel router; the single tunnel
router identifies the target access point as the destination of the
encapsulated downlink packets destined for the user equipment based
on the outer header and provides the encapsulated downlink packets
destined for the user equipment to the target access point; and the
target access point decapsulates the encapsulated downlink packets
destined for the user equipment.
[0203] In another further example, the other method further
comprises: obtaining a notification that the handover has occurred;
and providing, to a map server, a registration message including a
mapping of an endpoint identifier of the user equipment to a single
routing locator for the single tunnel router, the registration
message including an indication that the single routing locator is
associated with the target access point, wherein based on the
registration message, the map server provides, to the single tunnel
router, a notification message including the mapping of the user
equipment to the single routing locator and an indication to
provide the downlink packets destined for the user equipment to the
target access point, and based on the notification message, the
single tunnel router provide the downlink packets destined for the
user equipment to the target access point.
[0204] In one example, a tunnel router associated with the source
access point is different from a tunnel router associated with the
target access point.
[0205] In a further example, the source access point replicates the
downlink packets destined for the user equipment to generate the
first copy of the downlink packets destined for the user equipment
and the second copy of the downlink packets destined for the user
equipment, encapsulates the first copy of the downlink packets
destined for the user equipment with the outer header to generate
the encapsulated downlink packets destined for the user equipment,
and provides the encapsulated downlink packets destined for the
user equipment to the tunnel router associated with the source
access point; the tunnel router associated with the source access
point identifies the target access point as the destination of the
encapsulated downlink packets destined for the user equipment based
on the outer header and provides the encapsulated downlink packets
destined for the user equipment to the tunnel router associated
with the target access point; the tunnel router associated with the
target access point identifies the target access point as the
destination of the encapsulated downlink packets destined for the
user equipment based on the outer header and provides the
encapsulated downlink packets destined for the user equipment to
the target access point; and the target access point decapsulates
the encapsulated downlink packets destined for the user
equipment.
[0206] In still another further example, the other method
comprises: obtaining a notification that the handover has occurred;
and providing, to a map server, a registration message including a
mapping of an endpoint identifier of the user equipment to the
tunnel router associated with the target access point, wherein
based on the registration message, the map server provides, to the
tunnel router associated with the target access point, a
notification message including the mapping of the user equipment to
the tunnel router associated with the target access point and an
indication to provide the downlink packets destined for the user
equipment to the target access point; and based on the notification
message, the tunnel router associated with the target access point
provides the downlink packets destined for the user equipment to
the target access point.
[0207] In one example, the method further comprises: obtaining a
notification that the target access point has stopped or will stop
decapsulating the encapsulated downlink packets destined for the
user equipment; and providing, to the source access point, an
indication to stop replicating the downlink packets destined for
the user equipment and encapsulating the downlink packets destined
for the user equipment with the outer header to generate the
encapsulated downlink packets destined for the user equipment.
[0208] In one example, the source access point is a first fourth
generation evolved Node B and the target access point is a second
fourth generation evolved Node B; the source access point is a
first fifth generation next generation Node B and the target access
point is a second fifth generation next generation Node B; or the
source access point is a first citizens broadband radio service
device and the target access point is a second citizens broadband
radio service device.
[0209] In another form, another apparatus is provided. The other
apparatus comprises: a network interface configured to obtain or
provide network communications; and one or more processors coupled
to the network interface, wherein the one or more processors are
configured to: obtain a notification that a handover is to occur
for a user equipment from a source access point to a target access
point; provide, to the target access point, an indication to
decapsulate encapsulated downlink packets destined for the user
equipment, wherein the encapsulated downlink packets destined for
the user equipment are encapsulated with an outer header
identifying the source access point as a source of the encapsulated
downlink packets destined for the user equipment and further
identifying the target access point as a destination of the
encapsulated downlink packets destined for the user equipment; and
provide, to the source access point, an indication to replicate
downlink packets destined for the user equipment to generate a
first copy of the downlink packets destined for the user equipment
and a second copy of the downlink packets destined for the user
equipment, and encapsulate the first copy of the downlink packets
destined for the user equipment with the outer header to generate
the encapsulated downlink packets destined for the user
equipment.
[0210] In another form, another one or more non-transitory computer
readable storage media are provided. The other one or more
non-transitory computer readable storage media are encoded with
instructions that, when executed by a processor, cause the
processor to: obtain a notification that a handover is to occur for
a user equipment from a source access point to a target access
point; provide, to the target access point, an indication to
decapsulate encapsulated downlink packets destined for the user
equipment, wherein the encapsulated downlink packets destined for
the user equipment are encapsulated with an outer header
identifying the source access point as a source of the encapsulated
downlink packets destined for the user equipment and further
identifying the target access point as a destination of the
encapsulated downlink packets destined for the user equipment; and
provide, to the source access point, an indication to replicate
downlink packets destined for the user equipment to generate a
first copy of the downlink packets destined for the user equipment
and a second copy of the downlink packets destined for the user
equipment, and encapsulate the first copy of the downlink packets
destined for the user equipment with the outer header to generate
the encapsulated downlink packets destined for the user
equipment.
[0211] The above description is intended by way of example only.
Although the techniques are illustrated and described herein as
embodied in one or more specific examples, it is nevertheless not
intended to be limited to the details shown, since various
modifications and structural changes may be made within the scope
and range of equivalents of the claims.
* * * * *