U.S. patent application number 17/291977 was filed with the patent office on 2021-10-14 for local identifier locator network protocol (ilnp) breakout.
This patent application is currently assigned to Telefonaktiebolaget LM Ericsson (publ). The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (publ). Invention is credited to David Ian ALLAN, Joel HALPERN.
Application Number | 20210321305 17/291977 |
Document ID | / |
Family ID | 1000005866164 |
Filed Date | 2021-10-14 |
United States Patent
Application |
20210321305 |
Kind Code |
A1 |
ALLAN; David Ian ; et
al. |
October 14, 2021 |
LOCAL IDENTIFIER LOCATOR NETWORK PROTOCOL (ILNP) BREAKOUT
Abstract
A method implemented by a network device functioning as a source
gNodeB in a cellular communication network to support incremental
deployment of identifier locator network protocol (ILNP) breakout
in the cellular communication network. The method includes sending
a list of data network names (DNNs) advertised by an access and
mobility management function (AMF) to a user equipment (UE),
receiving from the UE a first request for a first session with an
ILNP session and service continuity (SSC) mode, facilitating the UE
establishing a first packet data network (PDN) session associated
with a UE selected DNN, where the first PDN session requests the
ILNP SSC mode, receiving from the UE a second request for a second
session to the selected DNN using a non-ILNP SSC mode, and
facilitating the UE establishing a second PDN session to the
selected DNN using the non-ILNP SSC mode.
Inventors: |
ALLAN; David Ian; (San Jose,
CA) ; HALPERN; Joel; (Leesburg, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (publ) |
Stockholm |
|
SE |
|
|
Assignee: |
Telefonaktiebolaget LM Ericsson
(publ)
Stockholm
SE
|
Family ID: |
1000005866164 |
Appl. No.: |
17/291977 |
Filed: |
November 7, 2018 |
PCT Filed: |
November 7, 2018 |
PCT NO: |
PCT/US18/59694 |
371 Date: |
May 6, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 36/0061 20130101;
H04W 36/0027 20130101; H04W 36/00835 20180801; H04W 36/22
20130101 |
International
Class: |
H04W 36/00 20060101
H04W036/00; H04W 36/22 20060101 H04W036/22 |
Claims
1. A method implemented by a network device functioning as a source
gNodeB in a cellular communication network to support incremental
deployment of identifier locator network protocol (ILNP) breakout
in the cellular communication network, the method comprising:
sending a list of data network names (DNNs) advertised by an access
and mobility management function (AMF) to a user equipment (UE);
receiving from the UE a first request for a first session with an
ILNP session and service continuity (SSC) mode; facilitating the UE
establishing a first packet data network (PDN) session associated
with a UE selected DNN, where the first PDN session requests the
ILNP SSC mode; receiving from the UE a second request for a second
session to the selected DNN using a non-ILNP SSC mode; and
facilitating the UE establishing a second PDN session to the
selected DNN using the non-ILNP SSC mode.
2. The method of claim 1, further comprising: receiving, from the
UE via the first PDN session, a first packet destined for a first
Correspondent Node (CN); forwarding the first packet to the first
CN via a user plane function (UPF) that implements ILNP SSC mode;
receiving, from the UE via the second PDN session, a second packet
destined for a second CN; and forwarding the second packet to the
second CN via the UPF in the core of the cellular communication
network.
3. The method of claim 1, further comprising: determining that the
UE is to be handed over to a target gNodeB that has ILNP breakout
capability; sending a handover request message to the target
gNodeB; receiving a handover request acknowledgement from the
target gNodeB; notifying the UE that the target gNodeB is ready;
and tearing down the session with a source user plane function
(UPF).
4. The method of claim 1, further comprising: receiving
notification from a service management function (SMF) to redirect
traffic for the UE to a target user plane function (UPF);
overwriting a destination locator in a header of a packet destined
for the UE with a locator associated with the target UPF; and
removing state associated with re-direction to the target UPF, in
response to a timer expiration.
5. The method of claim 1, further comprising receiving a third
packet destined for a second UE that is not connected to the
gNodeB; querying a mapping system for a locator of the second UE;
receiving a reply from the mapping system indicating the locator of
the second UE; overwriting a destination locator in a header of the
third packet with the locator indicated by the reply received from
the mapping system; and forwarding the third packet.
6. A method implemented by a user equipment (UE) in a cellular
communication network to support incremental deployment of
identifier locator network protocol (ILNP) breakout in the cellular
communication network, the method comprising: receiving an
advertisement for a list of data network names (DNNs) from a source
gNodeB; establishing a first PDN session associated with a DNN
selected from the list using an ILNP session and service continuity
(SSC) mode; establishing a second PDN session associated with the
selected DNN using a non-ILNP SSC mode; sending traffic destined
for a first Correspondent Node (CN) that is ILNP capable via the
first PDN session; and sending traffic destined for a second CN
that is not ILNP capable via the second PDN session.
7. The method of claim 6, further comprising: receiving an
indication from the source gNodeB that the UE is to be handed over
to a target gNodeB; disconnecting from the source gNodeB;
connecting to the target gNodeB; and sending a redirect message to
the first CN that indicates how the UE can be reached.
8. The method of claim 7, wherein the target gNodeB has ILNP
breakout capability, and wherein the redirect message indicates
that the UE can be reached using a locator assigned to the UE at
the target gNodeB.
9. The method of claim 7, further comprising: receiving traffic
buffered at the target gNodeB that was forwarded by the source
gNodeB to the target gNodeB.
10. The method of claim 7, wherein the target gNodeB does not have
ILNP breakout capability, and wherein the redirect message
indicates that the UE can be reached using a locator associated
with a user plane function (UPF) in the core of the cellular
communication network.
11. A network device to function as a source gNodeB in a cellular
communication network to support incremental deployment of
identifier locator network protocol (ILNP) breakout in the cellular
communication network, the network device comprising: a
non-transitory computer-readable medium having stored therein an
ILNP breakout component; and a set of one or more processors
coupled to the non-transitory computer-readable medium, the set of
one or more processors to execute the ILNP breakout component, the
ILNP breakout component to send a list of data network names (DNNs)
advertised by an access and mobility management function (AMF) to a
user equipment (UE), to receive from the UE a first request for a
first session with an ILNP session and service continuity (SSC)
mode, to facilitate the UE establishing a first packet data network
(PDN) session associated with a UE selected DNN, where the first
PDN session requests the ILNP SSC mode, to receive from the UE a
second request for a second session to the selected DNN using a
non-ILNP SSC mode, and to facilitate the UE establishing a second
PDN session to the selected DNN using the non-ILNP SSC mode.
12. The network device of claim 11, wherein the ILNP breakout
component, when executed by the set of one or more processors,
further causes the network device to receive, from the UE via the
first PDN session, a first packet destined for a first
Correspondent Node (CN), forward the first packet to the first CN
via a user plane function (UPF) that implements ILNP SSC mode,
receive, from the UE via the second PDN session, a second packet
destined for a second CN, and forward the second packet to the
second CN via the UPF in the core of the cellular communication
network.
13. The network device of claim 11, wherein the ILNP breakout
component, when executed by the set of one or more processors,
further causes the network device to determine that the UE is to be
handed over to a target gNodeB that has ILNP breakout capability,
to send a handover request message to the target gNodeB, to receive
a handover request acknowledgement from the target gNodeB, to
notify the UE that the target gNodeB is ready, and to tear down the
session with a source user plane function (UPF).
14. A user equipment (UE) to operate in a cellular communication
network that supports incremental deployment of identifier locator
network protocol (ILNP) breakout in the cellular communication
network, the UE comprising: a non-transitory computer-readable
medium having stored therein an ILNP breakout component; and a set
of one or more processors coupled to the non-transitory
computer-readable medium, the set of one or more processors to
execute the ILNP breakout component, which causes the UE to receive
an advertisement for a list of data network names (DNNs) from a
source gNodeB, to establish a first PDN session associated with a
DNN selected from the list using an ILNP session and service
continuity (SSC) mode, to establish a second PDN session associated
with the selected DNN using a non-ILNP SSC mode, to send traffic
destined for a first Correspondent Node (CN) that is ILNP capable
via the first PDN session, and to send traffic destined for a
second CN that is not ILNP capable via the second PDN session.
15. The UE of claim 14, wherein the ILNP breakout component, when
executed by the set of one or more processors, further causes the
UE to receive an indication from the source gNodeB that the UE is
to be handed over to a target gNodeB, disconnect from the source
gNodeB, to connect to the target gNodeB, and to send a redirect
message to the first CN that indicates how the UE can be
reached.
16. The UE of claim 15, wherein the target gNodeB has ILNP breakout
capability, and wherein the redirect message indicates that the UE
can be reached using a locator assigned to the UE at the target
gNodeB.
17. The UE of claim 15, wherein the ILNP breakout component, when
executed by the set of one or more processors, further causes the
UE to receive traffic buffered at the target gNodeB that was
forwarded by the source gNodeB to the target gNodeB.
18. The UE of claim 15, wherein the target gNodeB does not have
ILNP breakout capability, and wherein the redirect message
indicates that the UE can be reached using a locator associated
with a user plane function (UPF) in the core of the cellular
communication network.
19. The UE of claim 15, wherein the redirect message is an Internet
Control Message Protocol (ICMP) redirect message.
20. The UE of claim 14, wherein the ILNP breakout component, when
executed by the set of one or more processors, further causes the
UE to send an update message to a mapping server that indicates how
the UE can be reached.
Description
TECHNICAL FIELD
[0001] Embodiments of the invention relate to the field of 5th
Generation (5G) mobile communication technology and more
specifically, to a method and system for using identifier locator
network protocol (ILNP) to enable a distributed gateway
architecture to improve efficiency in a 5G network by eliminating
inefficiency related to the use of anchor points and further
methods for efficiently managing handover of user equipment between
attachment points.
BACKGROUND
[0002] Referring to FIG. 1, cellular communication networks enable
user equipment (UE) 101, such as cellular phones and similar
computing devices, to communicate using spread spectrum radio
frequency communication. The UE 101 communicates directly with a
radio access network (RAN). The RAN includes a set of base stations
such as 5G new radio (NR) base stations, referred to as gNodeB 103.
FIG. 1 is a diagram of an example architecture for a cellular
communication system consistent with 5G cellular communication
architecture including an example UE 101 communicating with a
gNodeB 103 of the network. The gNodeB 103 interfaces with a packet
core network or 5G network core (5GC) 115 that connects the UE to
other devices in the cellular communication network and with
devices external to the cellular communication network.
[0003] The 5GC 115 and its components are responsible for enabling
communication between the UE 101 and other devices both internal
and external to the cellular communication system. The 5GC 115
includes a user plane function (UPF) 105, a session management
function (SMF) 123, an access and mobility management function
(AMF) 109 and similar components. Additional components are part of
the 5GC 115, but the components with less relevance to the handling
of the UE 101 and its mobility have been excluded for clarity and
to simplify the representation. The UE 101 may change the gNodeB
103 through which it communicates with the network as it moves
about geographically. The AMF 109, UPF 105 and SMF 123 coordinate
to facilitate this mobility of the UE 101 without interruption to
any ongoing telecommunication session of the UE 101.
[0004] The AMF 109 is a control node that, among other duties, is
responsible for connection and mobility management tasks. The UE
101 sends connection, mobility, and session information to the AMF
109, which manages the connection and mobility related tasks. The
SMF handles session management for the UE 101.
[0005] The UPF 105 provides anchor points for a UE 101 enabling
various types of transitions that facilitate the mobility of the UE
101 without the UE losing connections with other devices. The UPF
105 routes and forwards data to and from the UE 101 while
functioning as a mobility anchor point for the UE 101 handovers
between gNodeBs 103 and between 5G, long term evolution (LTE) and
other 3GPP technologies. The UPF 105 also provides connectivity
between the UE 101 and external data packet networks by being a
fixed anchor point that offers the UE's Internet Protocol (IP)
address into a routable packet network.
[0006] As shown in the example simplified network of FIG. 1, a UE
101 communicates with the 5GC 115 via the gNodeB 103 and reaches a
correspondent 113, or 121 via a UPF 105. In this example, the
traffic from the UE 101 would traverse the connected gNodeB 103,
and the UPF 105, to reach a correspondent 113. The correspondents
113, 121 can be any device capable of receiving the traffic from
the UE 101 and sending traffic to the UE 101 including cellular
phones, computing devices and similar devices that may be connected
through any number of intermediate networking or computing
devices.
SUMMARY
[0007] In one embodiment, a method is implemented by a network
device functioning as a source gNodeB in a cellular communication
network to support incremental deployment of identifier locator
network protocol (ILNP) breakout in the cellular communication
network. The method includes sending a list of data network names
(DNNs) advertised by an access and mobility management function
(AMF) to a user equipment (UE), receiving from the UE a first
request for a first session with an ILNP session and service
continuity (SSC) mode, facilitating the UE establishing a first
packet data network (PDN) session associated with a UE selected
DNN, where the first PDN session requests the ILNP SSC mode,
receiving from the UE a second request for a second session to the
selected DNN using a non-ILNP SSC mode, and facilitating the UE
establishing a second PDN session to the selected DNN using the
non-ILNP SSC mode.
[0008] In another embodiment, a method is implemented by the UE in
a cellular communication network to support incremental deployment
of ILNP breakout in the cellular communication network. The method
of the UE includes receiving an advertisement for a list of DNNs
from a source gNodeB, establishing a first PDN session associated
with a DNN selected from the list using an ILNP SSC mode,
establishing a second PDN session associated with the selected DNN
using a non-ILNP SSC mode, sending traffic destined for a first
correspondent node (CN) that is ILNP capable via the first PDN
session, and sending traffic destined for a second CN that is not
ILNP capable via the second PDN session.
[0009] In another embodiment, a network device to function as a
source gNodeB in a cellular communication network implements a
method to support incremental deployment of ILNP breakout in the
cellular communication network. The network device includes a
non-transitory computer-readable medium having stored therein an
ILNP breakout component, and a set of one or more processors
coupled to the non-transitory computer-readable medium. The set of
one or more processors execute the ILNP breakout component. The
ILNP breakout component sends a list of DNNs advertised by an AMF
to the UE, receives from the UE a first request for a first session
with an ILNP SSC mode, facilitates the UE establishing a first PDN
session associated with a UE selected DNN, where the first PDN
session requests the ILNP SSC mode, receives from the UE a second
request for a second session to the selected DNN using a non-ILNP
SSC mode, and facilitates the UE establishing a second PDN session
to the selected DNN using the non-ILNP SSC mode.
[0010] In a further embodiment, the UE to operate in a cellular
communication network implements a method that supports incremental
deployment of ILNP breakout in the cellular communication network.
The UE including a non-transitory computer-readable medium having
stored therein an ILNP breakout component, and a set of one or more
processors coupled to the non-transitory computer-readable medium.
The set of one or more processors to execute the ILNP breakout
component, which causes the UE to receive an advertisement for a
list of DNNs from a source gNodeB, to establish a first PDN session
associated with a DNN selected from the list using an ILNP SSC
mode, to establish a second PDN session associated with the
selected DNN using a non-ILNP SSC mode, to send traffic destined
for a first CN that is ILNP capable via the first PDN session, and
to send traffic destined for a second CN that is not ILNP capable
via the second PDN session.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention may best be understood by referring to the
following description and accompanying drawings that are used to
illustrate embodiments of the invention. In the drawings:
[0012] FIG. 1 is a diagram of one embodiment of a 5G network
architecture.
[0013] FIG. 2 is a diagram of one embodiment of a 5G network
architecture incremental deployment of ILNP breakout, according to
some embodiments.
[0014] FIG. 3A is a diagram of one embodiment illustrating
operations of a handover process when a UE is handed over between
gNodeBs that have ILNP breakout capability, according to some
embodiments.
[0015] FIG. 3B is a diagram of one embodiment illustrating
operations of a handover process when a UE is handed over from a
gNodeB that does not have ILNP breakout capability to a gNodeB that
has ILNP breakout capability, according to some embodiments.
[0016] FIG. 3C is a diagram of one embodiment illustrating
operations of a handover process when a UE is handed over between
gNodeBs that do not have ILNP breakout capability, according to
some embodiments.
[0017] FIG. 4 is a diagram of one embodiment of a handover call
flow, according to some embodiments.
[0018] FIG. 5 is a flow diagram of one embodiment of a process
performed by a gNodeB to support incremental deployment of ILNP
breakout, according to some embodiments.
[0019] FIG. 6A is a flow diagram of one embodiment of a handover
process performed by a source gNodeB, according to some
embodiments.
[0020] FIG. 6B is a flow diagram of one embodiment of a handover
process performed by a source UPF, according to some
embodiments.
[0021] FIG. 7 is a flow diagram of a handover process performed by
a target gNodeB, according to some embodiments.
[0022] FIG. 8 is a flow diagram of a process performed by a UE to
support incremental deployment of ILNP breakout, according to some
embodiments.
[0023] FIG. 9 is a flow diagram of a handover process performed by
a UE, according to some embodiments.
[0024] FIG. 10A illustrates connectivity between network devices
(NDs) within an exemplary network, as well as three exemplary
implementations of the NDs, according to some embodiments.
[0025] FIG. 10B illustrates an exemplary way to implement a
special-purpose network device according to some embodiments.
[0026] FIG. 10C illustrates various exemplary ways in which virtual
network elements (VNEs) may be coupled according to some
embodiments.
[0027] FIG. 10D illustrates a network with a single network element
(NE) on each of the NDs, and within this straight forward approach
contrasts a traditional distributed approach (commonly used by
traditional routers) with a centralized approach for maintaining
reachability and forwarding information (also called network
control), according to some embodiments.
[0028] FIG. 10E illustrates the simple case of where each of the
NDs implements a single NE, but a centralized control plane has
abstracted multiple of the NEs in different NDs into (to represent)
a single NE in one of the virtual network(s), according to some
embodiments.
[0029] FIG. 10F illustrates a case where multiple VNEs are
implemented on different NDs and are coupled to each other, and
where a centralized control plane has abstracted these multiple
VNEs such that they appear as a single VNE within one of the
virtual networks, according to some embodiments.
[0030] FIG. 11 illustrates a general-purpose control plane device
with centralized control plane (CCP) software 1150), according to
some embodiments.
DETAILED DESCRIPTION
[0031] The following description sets forth methods and system for
incrementally deploying identifier locator network protocol (ILNP)
breakout in a cellular communication network such as a 5.sup.th
generation (5G) mobile architecture network. ILNP breakout uses
ILNP to enable a distributed gateway architecture to improve
efficiency in a 5G network by eliminating inefficiency related to
the use of anchor points and distributing gateway functionality
closer to the edge of the network. ILNP is an enabler of this as it
addresses seamless session mobility without the use of anchor
points. The 5G architecture and the geographic placement of its
components is driven by both technical and business considerations
and requires specific functionalities and functional distributions
to be carried forward in any update to the architecture.
Embodiments provide improved efficiency while preserving the key
functionalities of the 5G architecture.
[0032] In the following description, numerous specific details such
as logic implementations, opcodes, means to specify operands,
resource partitioning/sharing/duplication implementations, types
and interrelationships of system components, and logic
partitioning/integration choices are set forth in order to provide
a more thorough understanding of the present invention. It will be
appreciated, however, by one skilled in the art that the invention
may be practiced without such specific details. In other instances,
control structures, gate level circuits and full software
instruction sequences have not been shown in detail in order not to
obscure the invention. Those of ordinary skill in the art, with the
included descriptions, will be able to implement appropriate
functionality without undue experimentation.
[0033] References in the specification to "one embodiment," "an
embodiment," "an example embodiment," etc., indicate that the
embodiment described may include a particular feature, structure,
or characteristic, but every embodiment may not necessarily include
the particular feature, structure, or characteristic. Moreover,
such phrases are not necessarily referring to the same embodiment.
Further, when a particular feature, structure, or characteristic is
described in connection with an embodiment, it is submitted that it
is within the knowledge of one skilled in the art to affect such
feature, structure, or characteristic in connection with other
embodiments whether or not explicitly described.
[0034] Bracketed text and blocks with dashed borders (e.g., large
dashes, small dashes, dot-dash, and dots) may be used herein to
illustrate optional operations that add additional features to
embodiments of the invention. However, such notation should not be
taken to mean that these are the only options or optional
operations, and/or that blocks with solid borders are not optional
in certain embodiments of the invention.
[0035] In the following description and claims, the terms "coupled"
and "connected," along with their derivatives, may be used. It
should be understood that these terms are not intended as synonyms
for each other. "Coupled" is used to indicate that two or more
elements, which may or may not be in direct physical or electrical
contact with each other, co-operate or interact with each other.
"Connected" is used to indicate the establishment of communication
between two or more elements that are coupled with each other.
[0036] An electronic device stores and transmits (internally and/or
with other electronic devices over a network) code (which is
composed of software instructions and which is sometimes referred
to as computer program code or a computer program) and/or data
using machine-readable media (also called computer-readable media),
such as machine-readable storage media (e.g., magnetic disks,
optical disks, solid state drives, read only memory (ROM), flash
memory devices, phase change memory) and machine-readable
transmission media (also called a carrier) (e.g., electrical,
optical, radio, acoustical or other form of propagated
signals--such as carrier waves, infrared signals). Thus, an
electronic device (e.g., a computer) includes hardware and
software, such as a set of one or more processors (e.g., wherein a
processor is a microprocessor, controller, microcontroller, central
processing unit, digital signal processor, application specific
integrated circuit, field programmable gate array, other electronic
circuitry, a combination of one or more of the preceding) coupled
to one or more machine-readable storage media to store code for
execution on the set of processors and/or to store data. For
instance, an electronic device may include non-volatile memory
containing the code since the non-volatile memory can persist
code/data even when the electronic device is turned off (when power
is removed), and while the electronic device is turned on that part
of the code that is to be executed by the processor(s) of that
electronic device is typically copied from the slower non-volatile
memory into volatile memory (e.g., dynamic random access memory
(DRAM), static random access memory (SRAM)) of that electronic
device. Typical electronic devices also include a set or one or
more physical network interface(s) (NI(s)) to establish network
connections (to transmit and/or receive code and/or data using
propagating signals) with other electronic devices. For example,
the set of physical NIs (or the set of physical NI(s) in
combination with the set of processors executing code) may perform
any formatting, coding, or translating to allow the electronic
device to send and receive data whether over a wired and/or a
wireless connection. In some embodiments, a physical NI may
comprise radio circuitry capable of receiving data from other
electronic devices over a wireless connection and/or sending data
out to other devices via a wireless connection. This radio
circuitry may include transmitter(s), receiver(s), and/or
transceiver(s) suitable for radiofrequency communication. The radio
circuitry may convert digital data into a radio signal having the
appropriate parameters (e.g., frequency, timing, channel,
bandwidth, etc.). The radio signal may then be transmitted via
antennas to the appropriate recipient(s). In some embodiments, the
set of physical NI(s) may comprise network interface controller(s)
(NICs), also known as a network interface card, network adapter, or
local area network (LAN) adapter. The NIC(s) may facilitate in
connecting the electronic device to other electronic devices
allowing them to communicate via wire through plugging in a cable
to a physical port connected to a NIC. One or more parts of an
embodiment of the invention may be implemented using different
combinations of software, firmware, and/or hardware.
[0037] A network device (ND) is an electronic device that
communicatively interconnects other electronic devices on the
network (e.g., other network devices, end-user devices). Some
network devices are "multiple services network devices" that
provide support for multiple networking functions (e.g., routing,
bridging, switching, Layer 2 aggregation, session border control,
Quality of Service, and/or subscriber management), and/or provide
support for multiple application services (e.g., data, voice, and
video).
[0038] The 5G architecture enables user equipment (UE) mobility by
hiding the true location of a UE from a correspondent node (CN) by
tunneling traffic to the UE via fixed anchor points (e.g., a user
plane function (UPF)) in the cellular communication network. This
allows the UE to change location without needing to change its
address (which as a consequence of the use of an anchor point and
tunnels appears as a geographically fixed location to
correspondents). However, the use of fixed anchor points may
introduce inefficiencies in the cellular communication network.
Traffic from a UE must be tunneled to the UPF before reaching a
correspondent node (CN), even if the CN is located in the same
network as the UE (e.g., a home network scenario), which can
introduce bandwidth and latency inefficiencies in the cellular
communication network. This can be further exacerbated if the
correspondent is also a UE anchored on a different UPF.
[0039] The UPF in the 5G network architecture implements specific
functionalities not easily dispensed with as they address business
and regulatory requirements. Embodiments avoid some of the
inefficiencies introduced by the use of fixed anchor points in the
5G network architecture by splitting the user plane functions of
each gateway from the control plane functions and distributing the
user plane functions to the gNodeBs. This can be done without
changing key aspects of the 5G network architecture if the control
plane functions remain in the centralized or invariant location.
Distributing the user plane functions near or to the gNodeBs
enables much of the traffic to avoid being tunneled to the
potentially distant components of the 5G network. The 5G network
architecture has split the anchor point into UPF and SMF, which
facilitates a distributed implementation by pinning the control
component.
[0040] Embodiments disclosed herein use ILNP to enable the
distribution of the user plane functions that allows traffic to be
broken out locally without having to go through potentially distant
anchor points (this ability to break out traffic locally using ILNP
may generally be referred to herein as "ILNP breakout").
[0041] ILNP is a network protocol that changes the semantics of an
Internet Protocol (IP) address to have two distinct namespaces. The
first namespace is referred to as an identifier and the second
namespace is referred to as a locator. The identifier is a
non-topological name for uniquely identifying a node. The locator
is a topologically bound name for an Internet Protocol (IP)
subnetwork and is hierarchically structured as per the IPv6
addressing plan. By separating identifier and locator, a device can
change locations within a network without the identity of the
device changing and therefore associated session state (e.g.
transmission control protocol (TCP) or IP security (IPSEC)) remains
valid independent of the device's point of attachment to the
network. The change in semantics of the IP address is transparent
to the network layer so routers in the network would forward IP
packets and ILNP packets in the same manner.
[0042] For a UE and a CN to communicate using ILNP, both the UE and
the CN need to implement ILNP. An entity (e.g., UE or CN) that
implements ILNP may be referred to herein as being ILNP capable. An
entity that does not implement ILNP may be referred to herein as
being non-ILNP capable. A UE cannot use ILNP for mobility if the CN
is not ILNP capable. Also, gNodeBs need to support procedures that
permit ILNP to operate as well as optionally have a co-located UPF
to enable seamless handover. However, it is foreseen that at least
initially, not all UEs and CNs will be ILNP capable and not all
gNodeBs will support procedures to enable ILNP operation. Thus,
there is a need to incrementally deploy ILNP breakout in a cellular
communication network.
[0043] Embodiments disclosed herein enable incremental deployment
of ILNP breakout in a 5G cellular communications network. The
embodiments adapt 5G session and service continuity (SSC) mode 2 as
a model for introduction and refer to it as the ILNP SSC mode. SSC
mode 2 is a network initiated UPF change with an address change.
The ILNP SSC mode is defined as a UE initiated UPF change with an
address change. The embodiments define the concept of a packet data
network (PDN) session type exclusively for ILNP traffic. A UE can
have a non-ILNP correspondent SSC mode session (typically mode 1, 2
or 3), and an ILNP correspondent session (ILNP SSC mode). The
non-ILNP PDN session handles both Internet Protocol version 4
(IPv4) and non-ILNP IPv6 traffic. This permits incremental
introduction side by side with the existing infrastructure of 5G
networks. The embodiments integrate ILNP into mobility handoff
procedures. The embodiments provide a split gateway architecture
for ILNP breakout but keep the traditional architecture for IPv4
and non-ILNP IPv6 traffic. The embodiments provide distributed UPFs
for ILNP IPv6. The embodiments utilize a "replacement" session, one
in which the serving UPF instance and the location of the UE
changes, but it is logically a continuation of the previous
session. The UPFs can be collapsed right down to the gNodeB for
ILNP breakout or simply placed considerably closer to the gNodeB
than that for anchored mobility as no anchor points are needed, but
in some deployments the supporting UPF may be placed deeper in the
network. Instead, the embodiments make the control plane ILNP
"aware." This indicates that the control plane has knowledge of
where the ILNP capability exists, as well as, when and where it can
be used. In some embodiments, IP multimedia systems (IMS) changes
are utilized when domain name service (DNS) is not used.
[0044] In the embodiments, a UE can determine a correspondent is
ILNP capable by any of several mechanisms including a DNS lookup of
identifier and locator (I+L) records, IMS call setup that has been
augmented to indicate that the correspondent is ILNP capable, an
unsolicited message that includes ILNP header options, or similar
mechanism. A UE in the embodiments will have two locators
associated with it, specifically, one locator associated with a PDN
session from the UE to a normal anchor point, and another locator
associated with a PDN session to the same data network but with
local breakout, used for communicating with ILNP capable peers. An
ILNP capable UE when connecting to the network may be provided with
a data network name (DNN) and will request two PDN sessions for
that DNN with SSC modes corresponding to ILNP and non-ILNP behavior
respectively. The first PDN session is used to communicate with
ILNP capable correspondents. The other PDN session is for non-ILNP
based communication. If the SMF or controlled UPF cannot support
ILNP operation, or the policies associated with the DNN for that UE
do not permit ILNP operation, then the ILNP SSC mode session
request is rejected and the UE defaults to using the non-ILNP
session for both ILNP and non-ILNP capable correspondents. Even if
a UE cannot locally exploit ILNP operation, it can still permit
ILNP capable correspondents to exploit it by continuing to
advertise ILNP capability. The non-ILNP capable PDN session (e.g.,
using SSC modes 1 to 3) directs traffic to a traditional UPF anchor
point. UEs without ILNP capability will not request an ILNP SSC
mode PDN session. If a UE is unsuccessful in establishing an ILNP
SSC mode session, then an ILNP capable UE forwards all traffic via
the existing non-ILNP access points as per network policy. A UE in
a visited network also forwards traffic via existing non-ILNP
access points where there was no local breakout. When choosing
between ILNP and non-ILNP sessions, the UE will select which
session to use on the basis of DNS lookups, ILNP header and/or
other similar options. If the peer is ILNP capable, then the UE
will send traffic via the ILNP SSC mode PDN session; if the peer is
not ILNP capable, then the UE sends via the non-ILNP PDN
session.
[0045] FIG. 2 is a diagram of one embodiment of a 5G network
architecture with distributed UPFs implementing an ILNP SSC mode
capability that enables incremental deployment of ILNP breakout.
The exemplary network architecture shown in the diagram enables the
UEs 101A, B to communicate with the CNs 117A, B. The network
architecture includes an ILNP capable UE 101A that is connected to
gNodeB 103A. The gNodeB 103A has a co-located UPF 127 that supports
ILNP breakout capability. The UPF 127 may apply policies, implement
quality of service (QoS), perform regulatory functions (e.g., legal
intercept), and perform other user plane functions typically
performed by UPFs in a traditional 5G network architecture. The UPF
127 is controlled by an SMF 123. The SMF 123 may respectively
control one or several corresponding UPFs 127 co-located at the
gNodeBs 103. The example 5G network architecture also includes a UE
101B that is connected to gNodeB 103B, which does not have
co-located ILNP breakout capability. UE 101B may or may not be ILNP
capable. For purposes of simplicity and clarity, the 5G network
architecture is shown as including a single ILNP breakout capable
gNodeB 103A and a single non-ILNP breakout capable gNodeB 103B. It
should be understood, however, that the 5G network architecture can
include additional gNodeBs 103.
[0046] The 5G network architecture also includes additional
components and entities such as access and mobility management
function (AMF) 109, and similar components. These entities perform
the same functions as performed in most other 5G network
architectures. The 5G network architecture also includes a mapping
server 125 that stores identifiers and locators for nodes (which
the UE 101 or other entity can use to look up the identifier and
locator for a particular node). In one embodiment, the mapping
server 125 is a domain name server (DNS) server (e.g., for general
Internet access) or an IMS server (e.g., for telephony).
[0047] As shown in the diagram, the UE 101A upon registration is
provided a DNN list that it has subscribed to, in this case the
list is a single DNN `A.` Associated with the DNN may be the
permissible non-ILNP SSC modes. The UE may also be provided with an
indication that the local gNodeB is ILNP capable. The UE will
establish a PDN session to the DNN using a non-ILNP SSC mode and
will establish a PDN session to the DNN using the ILNP SSC mode.
The UE 101 may then select a different PDN session to use when
communicating with a CN 117 depending on whether the CN 117 is ILNP
capable. For example, the UE 101A may communicate with ILNP capable
CN 117A using one PDN session, which directs traffic over a
datapath 131 that goes through UPF 127. However, UE 101A may
communicate with non-ILNP capable CN 117B using another PDN
session, which directs traffic over datapath 133 that goes through
an anchor point. A UE 101 may determine whether a CN 117 is ILNP
capable based on looking up the CN 117 in the mapping server 125
(e.g., where the mapping server is a DNS server) or based on
information in a packet received from the CN 117 indicating that
the CN 117 is ILNP capable (e.g., in a header of the packet). In
this way, the UE 101A takes advantage of ILNP breakout capabilities
when communicating with an ILNP capable CN 117A but uses
traditional network access mechanisms (via anchor points) when
communicating with a non-ILNP capable CN 117B or for IPv4 traffic,
which allows for the incremental deployment of ILNP breakout.
[0048] In contrast to the UE 101A, the UE 101B is attached to the
gNodeB 103B that does not have ILNP breakout capability. Thus, the
UE 101B will not be able to establish a PDN session that uses the
ILNP SSC mode or will have the session directed to an anchor point
UPF by SMF procedures. The UE 101B communicates with ILNP capable
CN 117A and non-ILNP capable CN 117B using this PDN session, which
directs traffic over datapath 135 that goes through anchor points.
It should be noted that if UE 101B is ILNP capable, then it may
still communicate with ILNP capable CN using ILNP so if the UE
moves to another location being served by a gNodeB that does
support ILNP breakout, then ILNP mobility procedures will permit a
resumption of the efficiencies of local ILNP breakout in serving
ILNP traffic.
[0049] In order to initiate an ILNP communication session with a CN
117, a UE 101 or other end system needs to know whether the CN 117
is ILNP capable. In one embodiment, the UE 101 consults with the
mapping server 125 to determine whether a CN 117 is ILNP capable.
For example, the mapping server may be a DNS server and the UE 101
may retrieve a DNS record corresponding to the CN 117 to determine
whether the CN 117 is ILNP capable. In mobile broadband, DNS is not
the only mechanism used to resolve peers (e.g., there is Session
Initiation Protocol (SIP) exchange based on telephony identifiers).
For purposes of this disclosure, it is assumed that at the time the
UE 101 desires to initiate communication with a CN 117, it has a
mechanism to know whether the CN 117 is ILNP capable (e.g., by
consulting a mapping server or via telephony signaling). It should
be noted that whether the CN is ILNP capable and whether the UE
will use ILNP procedures in communicating with ILNP capable
correspondents is independent of whether ILNP breakout is
available.
[0050] A UE 101 (e.g., UE 101A) that has established multiple PDN
sessions effectively has multiple bearers. For functionally
equivalent connectivity to both the ILNP breakout PDN session and
the traditional PDN session, the Service Data Flow (SDF) templates
for both may be the same. Also, the AMF 109 may need to know the
location of the UE 101 for tracking and paging purposes. Thus, in
one embodiment, the UE 101 registers with the AMF 109.
[0051] In a cellular communication network, a UE 101 may change the
gNodeB 103 to which it connects as it moves about geographically.
The process of switching between gNodeBs 103 is generally referred
to as a handover process. During incremental deployment of ILNP
breakout, the cellular communication network may include gNodeBs
103 that have ILNP breakout capability as well as gNodeBs 103 that
do not have ILNP breakout capability. Thus, the UE 101 may be
handed over between gNodeBs that have ILNP breakout capability,
between gNodeBs that do not have ILNP breakout capability, and
between a gNodeB that has ILNP breakout capability and a gNodeB
that does not have ILNP breakout capability, and vice versa.
Existing X2 assisted handover may not be applicable or may need to
be modified to support seamless handover for these various
scenarios without losing session continuity or providing a
discontinuity in traffic delivery. The handover process for these
various scenarios are shown in FIGS. 3A-C and described herein
below.
[0052] FIG. 3A is a diagram illustrating operations of a handover
process when a UE is handed over between gNodeBs that have ILNP
breakout capability, according to some embodiments. At operation 1,
the UE 101 triggers the handover process when it moves from the
source gNodeB 103A toward the target gNodeB 103B, where both the
source gNodeB 103A and the target gNodeB have ILNP breakout
capability. As a result, the UE 101 disconnects from the source
gNodeB 103A and starts connecting to the target gNodeB 103B. Even
after the UE 101 disconnects from the source gNodeB 103A, the CN
117 continues to send traffic for the UE 101 to the source UPF 127
(since it may not yet know that the UE 101 has moved). At operation
2, the source UPF 127 forwards traffic for the UE 101 to the target
UPF 301 by overwriting the locator (e.g., in the header of a
packet) with a locator associated with the target UPF 301. The
target UPF forwards the traffic to the target gNodeB 103B. At
operation 3, the target gNodeB 103B buffers the forwarded traffic.
At operation 4, the target gNodeB 103B sends the buffered traffic
to the UE 101. At operation 5, the UE 101 sends a redirect message
(e.g., Internet Control Message Protocol (ICMP) redirect message)
to the CN 117 that indicates that UE 101 can be reached using its
new locator (which may be the same as the locator associated with
the target UPF 301 that was used to overwrite the locator at
operation 2, depending on implementation).
[0053] FIG. 3B is a diagram illustrating operations of a handover
process when a UE is handed over from a gNodeB that does not have
ILNP breakout capability to a gNodeB that has ILNP breakout
capability, according to some embodiments. At operation 1, the UE
101 triggers the handover process when it moves from the source
gNodeB 103A toward the target gNodeB 103B, where the source gNodeB
103A does not have ILNP breakout capability and the target gNodeB
103B has ILNP breakout capability. As a result, the UE 101
disconnects from the source gNodeB 103A and starts connecting to
the target gNodeB 103B. Even after the UE 101 disconnects from the
source gNodeB 103A, the CN 117 continues to send traffic for the UE
101 to the source gNodeB 103A (since it may not yet know that the
UE 101 has moved). At operation 2, the source gNodeB 103A forwards
traffic for the UE 101 to the target gNodeB 103B over an X2 tunnel.
At operation 3, the target gNodeB 103B buffers the forwarded
traffic. At operation 4, the target gNodeB 103B sends the buffered
traffic to the UE 101. At operation 5, the UE requests an ILNP SSC
mode session to the DNN by a request to the SMF sent via the AMF.
Upon completion of session setup, at operation 6, the UE 101 sends
a redirect message (e.g., ICMP Redirect message) to the CN 117 that
indicates that the UE 101 can be reached using its new locator
associated with a re-established ILNP SSC mode session.
[0054] FIG. 3C is a diagram illustrating operations of a handover
process when a UE is handed over between gNodeBs that do not have
ILNP breakout capability, according to some embodiments. The
operations of this handover process remain the same as the X2
assisted handover process employed in traditional 3GPP
architectures. At operation 1, the UE 101 triggers the handover
process when it moves from the source gNodeB 103A toward the target
gNodeB 103B, where both the source gNodeB 103A and the target
gNodeB do not have ILNP breakout capability. As a result, the UE
101 disconnects from the source gNodeB 103A and starts connecting
to the target gNodeB 103B. Even after the UE 101 disconnects from
the source gNodeB 103A, the CN 117 continues to send traffic for
the UE 101 to the source gNodeB 103A (since it may not yet know
that the UE 101 has moved). At operation 2, the source gNodeB 103A
forwards traffic for the UE 101 to the target gNodeB 103B over an
X2 tunnel. At operation 3, the target gNodeB 103B buffers the
forwarded traffic. At operation 4, the target gNodeB 103B sends the
buffered traffic to the UE 101. It should be noted that in this
scenario, the locator for the UE 101 does not change and thus the
UE 101 does not need to send a redirect message to the CN 117 (even
if it is communicating with the CN 117 using ILNP).
[0055] FIG. 4 is a diagram of one embodiment of a handover call
flow. The call flow primarily illustrates the entities and calls
involved in the ILNP handover. Thus, other entities and calls
related to the overall handover process may not be illustrated for
sake of clarity. As is common and well understood practice,
transactions may be acknowledged, and if a transaction initiator
does not receive an acknowledgement in a specified time interval,
the transaction initiator can retry the transaction. This can
repeat for a specified number of times before the operation is
considered to have failed.
[0056] UE 101 is initially connected to source gNodeB 103A and
communicates with CN 117 over a datapath that goes through source
gNodeB 103A and source UPF 127. Subsequently, source gNodeB 103A
determines that the UE 101 is to be handed over to the target
gNodeB 103B (i.e., the source gNodeB 103A makes a handover
decision). In response to determining that the UE 101 is to be
handed over to the target gNodeB 103B, the source gNodeB 103A
begins a handover preparation process. In some embodiments, the
source gNodeB 103A sends an augmented X2 Handoff message to the
target gNodeB 103B. Based on receiving the augmented X2 Handoff
message, the target gNodeB 103B may know to expect traffic destined
for the UE 101. The augmented X2 Handoff message may include
information regarding radio access bearer (RAB), quality of service
(QoS), ILNP breakout capability, and policy filters (e.g.,
downstream service filters). A session at the target gNodeB is set
up. In some embodiments, the target gNodeB 103B requests a parallel
session to be set up using a path setup request to the AMF 109. The
AMF 109 relays the request to the SMF 123. The SMF 123 selects a
target UPF 151 that may be co-located with the target gNodeB 103B,
or in scenarios where the target UPF 151 may not be directly
co-located with the target gNodeB 103B, and in some scenarios may
not be required to change to support the handover. When a change is
required, the target UPF 151 is programmed with session state to
mirror the source UPF 127 by the SMF 123 (e.g., using the N4
session). The SMF 123 initiates session setup between the target
gNodeB 103B and the target UPF 151. Upon completion of the session
setup, the SMF 123 then provides a locator for the target UPF 151
to the source UPF 127 for redirecting traffic. The target gNodeB
103B responds to the augmented X2 Handoff message by sending an
augmented X2 Handoff Acknowledgement (ACK) message to the source
gNodeB 103A. The SMF 123 communicates to the source gNodeB 103A as
relayed by the AMF 109 that the session is ready for handover. The
source gNodeB 103A communicates with the UE 101 to initiate the
actual handover.
[0057] After the UE 101 has disconnected from the source gNodeB
103A, the CN 117 continues to send traffic destined for the UE 101
to the source UPF 127 over the downstream datapath (since it may
not yet know that the UE 101 has moved). The source UPF 127
forwards this traffic to the target UPF 151 by overwriting the
locator (e.g., in a packet header). The target UPF 151 forwards the
traffic to the target gNodeB 103B. The target gNodeB 103B knows
that the UE 101 is going to connect with the target gNodeB 103B so
the target gNodeB 103B buffers the forwarded traffic until the UE
101 connects. At this point, the target UPF 151 may have an
upstream datapath to the CN 117. The UE 101 then disconnects from
the source gNodeB 103A. Subsequently, the UE 101 synchronizes and
connects to the target gNodeB 103B. Once the UE 101 connects to the
target gNodeB 103B, the target gNodeB 103B sends the buffered
traffic to the UE 101. Also, the target gNodeB 103B sends a path
switch message directed to the SMF 123 indicating that the source
UPF session can be discontinued. This path switch message is
forwarded to the AMF 109 and then to the SMF 123.
[0058] The SMF 123 sends a locator to the UE 101 via the target UPF
151. This will typically be in the form of a stateless
auto-configuration (SLAAC) router advertisement (RA). The UE 101
notes if the locator for the session has changed, and if so then
sends an ICMP redirect message to the CN 117 that indicates that
the UE 101 can now be reached via target UPF 151. The UE 101 may
have remembered the CN 117 it was communicating with based on
information stored in the UE's 101 Identifier Locator Communication
Cache (ILCC) (ILCC is an ILNP construct that tracks the set of CNs
117, their IDs, session nonces, and other relevant state (e.g.,
timers for redirect ACKs)). The CN 117 responds by sending an ICMP
redirect ACK message to the UE 101. The UE 101 can then communicate
with the CN 117 over a datapath that goes through the target gNodeB
103B and handover is complete. The SMF 123 can message the source
UPF 127 to release session resources.
[0059] It is also possible to envision other scenarios that have
mobility implications without a handoff having occurred. For
example, this would be when a UE 101 goes idle and changes
locations while idle. In this scenario, it would be possible that a
UPF 127 received a packet directed to a UE 101 not connected to the
network. In this scenario, the UPF 127 may buffer the packet and
request the SMF 123 for a location to forward the packet to. If the
UE 101 is still idle, the SMF 123 may initiate paging procedures to
wake up the UE 101, and advise the UPF 127 of the resulting
location of the UE 101. If the new location was not local to the
UPF 127, the UPF 127 may perform prefix modification on the
buffered packet, and then forward it to the appropriate UPF for
delivery to the UE 101.
[0060] It is possible to also consider various race conditions such
that packets are relayed to a UE 101 by the network on the basis of
stale information combined with either handoff or paging
procedures. The nature of the forwarding mechanism is such that the
fact that the packet was sent via a stale locator is hidden from
the UE 101. For existing CNs 117, the normal ILNP procedures of
sending an ICMP Redirect message will address the locator freshness
issue. As a part of this embodiment, UEs 101 may send an ICMP
Redirect message to all new CNs 117 to ensure that the CNs have
fresh locator information in their respective ILCCs.
[0061] FIG. 5 is a flow diagram of a process performed by a gNodeB
to support incremental deployment of ILNP breakout, according to
some embodiments. The operations in the flow diagrams will be
described with reference to the exemplary embodiments of the other
figures. However, it should be understood that the operations of
the flow diagrams can be performed by embodiments of the invention
other than those discussed with reference to the other figures, and
the embodiments of the invention discussed with reference to these
other figures can perform operations different than those discussed
with reference to the flow diagrams.
[0062] At block 510, the gNodeB 103 forwards an AMF 109 advertised
subscribed DNN list to a UE 101. At block 515, the gNodeB 103
receives a request from the UE 101 for a first session associated
with the selected DNN where the UE requests an ILNP SSC mode. At
block 520, the gNodeB (along with the AMF and SMF) facilitates the
UE 101 establishing a first PDN session associated with a UE 101
selected DNN, where the first PDN session requests the ILNP SSC
mode. At block 530, the UE 101 requests a second session and the
gNodeB (along with AMF and SMF) facilitates the UE 101 establishing
a second PDN session to the selected DNN using a non-ILNP SSC mode
(block 535). At block 540, the gNodeB 103 receives, from the UE 101
via the first PDN session, a first packet destined for a first CN
117A (the first CN 117A may be a CN 117 that the UE 101 determined
is ILNP capable). At block 550, the gNodeB 103 forwards the first
packet to the first CN 117A via the UPF 127 where the UPF 127
supports the ILNP SSC mode. At block 560, the gNodeB 103 receives,
from the UE 101 via the second PDN session, a second packet
destined for a second CN 117B (the second CN 117B may be a CN 117
that the UE 101 determined is not ILNP capable). At block 570, the
gNodeB 103 forwards the second packet to the second CN 117B via the
UPF 171 in the core of the cellular communication network.
[0063] In one embodiment, the UPF 127 receives a third packet
destined for a second UE 101 that is not served by the UPF 127
(e.g., not connected to the gNodeB 103). In this case, the UPF 127
may query an SMF 123 for a locator of the second UE 101. The UPF
127 may then receive a reply from the SMF 123 indicating the
locator of the second UE 101 (e.g., AMF 109 may determine the
locator of the second UE 101 based on performing paging
procedures). The UPF 127 may then overwrite a destination locator
in a header of the third packet with the locator received from the
SMF 123 and forward the third packet.
[0064] FIG. 6A is a flow diagram of a handover process performed by
a source gNodeB, according to some embodiments. At block 610, the
source gNodeB 103A determines that a UE 101 is to be handed over to
a target gNodeB 103B. The determination can be based on a
notification received from the UE 101 or other component that
identifies a target gNodeB 103B. At block 620, the source gNodeB
103A sends a handover request message to the target gNodeB 103B
(which indicates that UE 101 is to be handed over to the target
gNodeB 103B). The handover request message may include information
regarding radio access bearer (RAB), quality of service (QoS), ILNP
breakout capability, and policy filters (e.g., downstream SDF
filter). At Block 625, the source gNodeB 103A may receive a
handover request acknowledgement message from the target gNodeB
103B if the target gNodeB 103B successfully receives the handover
request message. The source gNodeB 103A then notifies the UE that
the target gNodeB 103B is ready for the handover, at block 630.
After this point, the UE 101 will disconnect from the source gNodeB
and the session between the UE 101 and the source gNodeB can be
torn down, at block 640.
[0065] FIG. 6B is a flowchart of one embodiment of a handover
process implemented by the source UPF 127. At block 650, the source
UPF 127 receives notification from the SMF 123 to redirect traffic
for the UE 101 to a target UPF. The notification can include the
locator or similar information for the target UPF. At block 660,
the source gNodeB 103A forwards the downstream packets for the UE
101 to the target gNodeB 103B using the locator of the target
gNodeB 103B. The SMF 123 can request or extract information from
the source UPF 127 related to accounting and policies that are to
be taken over by the target UPF. Upstream data traffic from the UE
101 can continue to be received by the source UPF 127 until
handover is completed and this upstream data traffic is forwarded
accordingly. The start of the redirection of the traffic intended
for the UE 101 can initiate a timer at the source UPF 127, and
after the expiration of the timer at block 670, the source UPF 127
ends the redirection of the traffic for the UE and removes the
sessions state associated with the redirection to the target
UPF/gNodeB. Alternatively, the SMF 123 can send a message to end
the redirection to the source UPF 127.
[0066] FIG. 7 is a flow diagram of a handover process performed by
a target gNodeB, according to some embodiments. At block 710, the
target gNodeB 103B receives a handover request message (e.g., an
augmented X2 Handoff message) from a source gNodeB 103A. In
response, at block 715, the target gNodeB 103B sends a handover
request acknowledgement message (e.g., an augmented X2 Handoff ACK
message) to the source gNodeB 103A. In one embodiment, the handover
request acknowledgement message includes information regarding
whether the target gNodeB 103B has ILNP breakout capability. The
target gNodeB 103B coordinates session set up via the SMF 123 with
the target UPF 151. At block 720, the target gNodeB 103B receives
and buffers traffic for a UE 101 forwarded from the source UPF 127.
At block 730, the target gNodeB 103B sends buffered traffic to the
UE 101 after the UE 101 connects to the target gNodeB 103B and
local session with the target UPF 151. At block 735, the target
gNodeB 103B sends a path switch request message to the SMF 123 via
an AMF 109. The path switch request message may inform the AMF 109
of the new locator of the UE 101 (and possibly the tracking area
(TA) for the UE 101). At block 740, the target gNodeB 103B relays a
redirect message originated by the UE 101 to a CN 117 that
indicates how the UE 101 can be reached.
[0067] FIG. 8 is a flow diagram of a process performed by a UE to
support incremental deployment of ILNP breakout, according to some
embodiments. At block 810, the UE 101 receives an advertisement of
a list of DNN from an AMF 109. At block 820, the UE 101 establishes
a first PDN session associated with a DNN selected from the list of
DNN, where the first PDN session uses the ILNP SSC mode. In one
embodiment, the UE 101 is provided with a locator to use for
communicating via the first PDN session. At block 830, the UE 101
establishes a second PDN session associated with the DNN using the
non-ILNP SSC mode. In one embodiment, the UE 101 is provided with
either a prefix or IPv6 address to use for communicating via the
second PDN session. At decision block 840, the UE 101 determines
whether a CN 117 is ILNP capable. In one embodiment, the UE 101
determines whether the CN 117 is ILNP capable based on looking up
information about the CN 117 in a mapping server 125 (e.g., DNS
server). If the CN 117 is ILNP capable, then at block 850, the UE
101 sends traffic to the CN 117 via the first PDN session using
ILNP procedures. However, if the CN 117 is not ILNP capable, then
at block 860, the UE 101 sends traffic to the CN 117 via the second
PDN session. In one embodiment, the UE 101 initially attempts to
establish ILNP communication with the CN 117 via the second PDN
session associated with the DNN (i.e., the non-ILNP SSC mode
session). If this succeeds (which indicates that the CN 117 is ILNP
capable), the UE 101 may switch to using the first PDN session
associated with the ILNP SSC mode to communicate with the CN 117.
In one embodiment, the UE 101 sends, to all CNs 117 that initiate
sessions with the UE 101, a redirect message that indicates how the
UE 101 can be reached (e.g., to ensure that all CNs 117 have fresh
locator information in their respective ILCCs).
[0068] FIG. 9 is a flow diagram of a handover process performed by
a UE, according to some embodiments. At block 910, the UE 101
receives an indication from a source gNodeB 103A that the UE 101 is
to be handed over to a target gNodeB 103B. At block 920, the UE 101
disconnects from the source gNodeB 103A. At block 930, the UE 101
connects to the target gNodeB 103B. In one embodiment, the UE 101
connects to the target gNodeB 103B before disconnecting from the
source gNodeB 103A. At block 940, the UE 101 receives traffic that
had been buffered at the target gNodeB 103B that was forwarded by
the source UPF 127. At decision block 950, the UE 101 determines
whether the target gNodeB 103B has ILNP breakout capability. In one
embodiment, the UE 101 determines whether the target gNodeB 103B
has ILNP breakout capability based on acceptance of an ILNP SSC
mode session establishment. If the target gNodeB 103B has ILNP
breakout capability, then at block 960, the UE 101 sends a redirect
message to a CN 117 that indicates that the UE 101 can be reached
using a locator assigned to the UE 101 at the target UPF 151.
However, if the target gNodeB 103B does not have ILNP breakout
capability, then at block 970, the UE 101 sends a redirect message
to a CN 117 that indicates that the UE 101 can be reached using a
locator associated with a UPF 171 in a core of a cellular
communication network. In one embodiment, the redirect message is
an ICMP Redirect message. At block 980, the UE 101 sends an update
message to a mapping server 125 that indicates how the UE 101 can
be reached.
[0069] In an alternate embodiment, the SMF simply selects a
non-local anchor point UPF 171 for the ILNP SSC mode session, and
the UE itself is unaware that ILNP breakout capability is not
locally available at the target gNodeB 103B.
[0070] An advantage of embodiments disclosed herein is that they
enable incremental deployment of ILNP breakout, while preserving
key aspects of the business interfaces of the 5G architecture.
Also, changes to the network are mostly confined to the UE 101, 5G
architecture components, and the end system stacks in CNs 117. That
is, there is no additional device added to the middle of the
network to enable the solution. The overhead of tunneling is
eliminated or reduced for ILNP capable CNs 117. Also, embodiments
disclosed herein allow a mobile carrier to control the pace of
transition (e.g., force voice over long term evolution (VoLTE) over
the traditional datapath with anchor points).
[0071] It is also possible to consider other embodiments consistent
with 5G Core procedures, such as a network initiated UPF change for
an ILNP SSC mode, or an SMF change coordinated with a UE initiated
UPF change.
[0072] FIG. 10A illustrates connectivity between network devices
(NDs) within an exemplary network, as well as three exemplary
implementations of the NDs, according to some embodiments of the
invention. FIG. 10A shows NDs 1000A-H, and their connectivity by
way of lines between 1000A-1000B, 1000B-1000C, 1000C-1000D,
1000D-1000E, 1000E-1000F, 1000F-1000G, and 1000A-1000G, as well as
between 1000H and each of 1000A, 1000C, 1000D, and 1000G. These NDs
are physical devices, and the connectivity between these NDs can be
wireless or wired (often referred to as a link). An additional line
extending from NDs 1000A, 1000E, and 1000F illustrates that these
NDs act as ingress and egress points for the network (and thus,
these NDs are sometimes referred to as edge NDs; while the other
NDs may be called core NDs).
[0073] Two of the exemplary ND implementations in FIG. 10A are: 1)
a special-purpose network device 1002 that uses custom
application-specific integrated-circuits (ASICs) and a
special-purpose operating system (OS); and 2) a general-purpose
network device 1004 that uses common off-the-shelf (COTS)
processors and a standard OS.
[0074] The special-purpose network device 1002 includes networking
hardware 1010 comprising a set of one or more processor(s) 1012,
forwarding resource(s) 1014 (which typically include one or more
ASICs and/or network processors), and physical network interfaces
(NIs) 1016 (through which network connections are made, such as
those shown by the connectivity between NDs 1000A-H), as well as
non-transitory machine readable storage media 1018 having stored
therein networking software 1020. During operation, the networking
software 1020 may be executed by the networking hardware 1010 to
instantiate a set of one or more networking software instance(s)
1022. Each of the networking software instance(s) 1022, and that
part of the networking hardware 1010 that executes that network
software instance (be it hardware dedicated to that networking
software instance and/or time slices of hardware temporally shared
by that networking software instance with others of the networking
software instance(s) 1022), form a separate virtual network element
1030A-R. Each of the virtual network element(s) (VNEs) 1030A-R
includes a control communication and configuration module 1032A-R
(sometimes referred to as a local control module or control
communication module) and forwarding table(s) 1034A-R, such that a
given virtual network element (e.g., 1030A) includes the control
communication and configuration module (e.g., 1032A), a set of one
or more forwarding table(s) (e.g., 1034A), and that portion of the
networking hardware 1010 that executes the virtual network element
(e.g., 1030A).
[0075] Software 1020 can include code such as ILNP breakout
component 1025, which when executed by networking hardware 1010,
causes the special-purpose network device 1002 to perform
operations of one or more embodiments of the present invention as
part networking software instances 1022.
[0076] The special-purpose network device 1002 is often physically
and/or logically considered to include: 1) a ND control plane 1024
(sometimes referred to as a control plane) comprising the
processor(s) 1012 that execute the control communication and
configuration module(s) 1032A-R; and 2) a ND forwarding plane 1026
(sometimes referred to as a forwarding plane, a user plane, or a
media plane) comprising the forwarding resource(s) 1014 that
utilize the forwarding table(s) 1034A-R and the physical NIs 1016.
By way of example, where the ND is a router (or is implementing
routing functionality), the ND control plane 1024 (the processor(s)
1012 executing the control communication and configuration
module(s) 1032A-R) is typically responsible for participating in
controlling how data (e.g., packets) is to be routed (e.g., the
next hop for the data and the outgoing physical NI for that data)
and storing that routing information in the forwarding table(s)
1034A-R, and the ND forwarding plane 1026 is responsible for
receiving that data on the physical NIs 1016 and forwarding that
data out the appropriate ones of the physical NIs 1016 based on the
forwarding table(s) 1034A-R.
[0077] FIG. 10B illustrates an exemplary way to implement the
special-purpose network device 1002 according to some embodiments
of the invention. FIG. 10B shows a special-purpose network device
including cards 1038 (typically hot pluggable). While in some
embodiments the cards 1038 are of two types (one or more that
operate as the ND forwarding plane 1026 (sometimes called line
cards), and one or more that operate to implement the ND control
plane 1024 (sometimes called control cards)), alternative
embodiments may combine functionality onto a single card and/or
include additional card types (e.g., one additional type of card is
called a service card, resource card, or multi-application card). A
service card can provide specialized processing (e.g., Layer 4 to
Layer 7 services (e.g., firewall, Internet Protocol Security
(IPsec), Secure Sockets Layer (SSL)/Transport Layer Security (TLS),
Intrusion Detection System (IDS), peer-to-peer (P2P), Voice over IP
(VoIP) Session Border Controller, Mobile Wireless Gateways (Gateway
General Packet Radio Service (GPRS) Support Node (GGSN), Evolved
Packet Core (EPC) Gateway)). By way of example, a service card may
be used to terminate IPsec tunnels and execute the attendant
authentication and encryption algorithms. These cards are coupled
together through one or more interconnect mechanisms illustrated as
backplane 1036 (e.g., a first full mesh coupling the line cards and
a second full mesh coupling all of the cards).
[0078] Returning to FIG. 10A, the general-purpose network device
1004 includes hardware 1040 comprising a set of one or more
processor(s) 1042 (which are often COTS processors) and physical
NIs 1046, as well as non-transitory machine-readable storage media
1048 having stored therein software 1050. During operation, the
processor(s) 1042 execute the software 1050 to instantiate one or
more sets of one or more applications 1064A-R. While one embodiment
does not implement virtualization, alternative embodiments may use
different forms of virtualization. For example, in one such
alternative embodiment the virtualization layer 1054 represents the
kernel of an operating system (or a shim executing on a base
operating system) that allows for the creation of multiple
instances 1062A-R called software containers that may each be used
to execute one (or more) of the sets of applications 1064A-R; where
the multiple software containers (also called virtualization
engines, virtual private servers, or jails) are user spaces
(typically a virtual memory space) that are separate from each
other and separate from the kernel space in which the operating
system is run; and where the set of applications running in a given
user space, unless explicitly allowed, cannot access the memory of
the other processes. In another such alternative embodiment the
virtualization layer 1054 represents a hypervisor (sometimes
referred to as a virtual machine monitor (VMM)) or a hypervisor
executing on top of a host operating system, and each of the sets
of applications 1064A-R is run on top of a guest operating system
within an instance 1062A-R called a virtual machine (which may in
some cases be considered a tightly isolated form of software
container) that is run on top of the hypervisor--the guest
operating system and application may not know they are running on a
virtual machine as opposed to running on a "bare metal" host
electronic device, or through para-virtualization the operating
system and/or application may be aware of the presence of
virtualization for optimization purposes. In yet other alternative
embodiments, one, some or all of the applications are implemented
as unikernel(s), which can be generated by compiling directly with
an application only a limited set of libraries (e.g., from a
library operating system (LibOS) including drivers/libraries of OS
services) that provide the particular OS services needed by the
application. As a unikernel can be implemented to run directly on
hardware 1040, directly on a hypervisor (in which case the
unikernel is sometimes described as running within a LibOS virtual
machine), or in a software container, embodiments can be
implemented fully with unikernels running directly on a hypervisor
represented by virtualization layer 1054, unikernels running within
software containers represented by instances 1062A-R, or as a
combination of unikernels and the above-described techniques (e.g.,
unikernels and virtual machines both run directly on a hypervisor,
unikernels and sets of applications that are run in different
software containers).
[0079] The instantiation of the one or more sets of one or more
applications 1064A-R, as well as virtualization if implemented, are
collectively referred to as software instance(s) 1052. Each set of
applications 1064A-R, corresponding virtualization construct (e.g.,
instance 1062A-R) if implemented, and that part of the hardware
1040 that executes them (be it hardware dedicated to that execution
and/or time slices of hardware temporally shared), forms a separate
virtual network element(s) 1060A-R.
[0080] The virtual network element(s) 1060A-R perform similar
functionality to the virtual network element(s) 1030A-R--e.g.,
similar to the control communication and configuration module(s)
1032A and forwarding table(s) 1034A (this virtualization of the
hardware 1040 is sometimes referred to as network function
virtualization (NFV)). Thus, NFV may be used to consolidate many
network equipment types onto industry standard high-volume server
hardware, physical switches, and physical storage, which could be
located in Data centers, NDs, and customer premise equipment (CPE).
While embodiments of the invention are illustrated with each
instance 1062A-R corresponding to one VNE 1060A-R, alternative
embodiments may implement this correspondence at a finer level
granularity (e.g., line card virtual machines virtualize line
cards, control card virtual machine virtualize control cards,
etc.); it should be understood that the techniques described herein
with reference to a correspondence of instances 1062A-R to VNEs
also apply to embodiments where such a finer level of granularity
and/or unikernels are used.
[0081] In certain embodiments, the virtualization layer 1054
includes a virtual switch that provides similar forwarding services
as a physical Ethernet switch. Specifically, this virtual switch
forwards traffic between instances 1062A-R and the physical NI(s)
1046, as well as optionally between the instances 1062A-R; in
addition, this virtual switch may enforce network isolation between
the VNEs 1060A-R that by policy are not permitted to communicate
with each other (e.g., by honoring virtual local area networks
(VLANs)).
[0082] Software 1050 can include code such as ILNP breakout
component 1063, which when executed by processor(s) 1042, cause the
general-purpose network device 1004 to perform operations of one or
more embodiments of the present invention as part software
instances 1062A-R.
[0083] The third exemplary ND implementation in FIG. 10A is a
hybrid network device 1006, which includes both custom
ASICs/special-purpose OS and COTS processors/standard OS in a
single ND or a single card within an ND. In certain embodiments of
such a hybrid network device, a platform VM (i.e., a VM that that
implements the functionality of the special-purpose network device
1002) could provide for para-virtualization to the networking
hardware present in the hybrid network device 1006.
[0084] Regardless of the above exemplary implementations of an ND,
when a single one of multiple VNEs implemented by an ND is being
considered (e.g., only one of the VNEs is part of a given virtual
network) or where only a single VNE is currently being implemented
by an ND, the shortened term network element (NE) is sometimes used
to refer to that VNE. Also, in all of the above exemplary
implementations, each of the VNEs (e.g., VNE(s) 1030A-R, VNEs
1060A-R, and those in the hybrid network device 1006) receives data
on the physical NIs (e.g., 1016, 1046) and forwards that data out
the appropriate ones of the physical NIs (e.g., 1016, 1046). For
example, a VNE implementing IP router functionality forwards IP
packets on the basis of some of the IP header information in the IP
packet; where IP header information includes source IP address,
destination IP address, source port, destination port (where
"source port" and "destination port" refer herein to protocol
ports, as opposed to physical ports of a ND), transport protocol
(e.g., user datagram protocol (UDP), Transmission Control Protocol
(TCP), and differentiated services code point (DSCP) values.
[0085] FIG. 10C illustrates various exemplary ways in which VNEs
may be coupled according to some embodiments of the invention. FIG.
10C shows VNEs 1230A.1-1230A.P (and optionally VNEs
1230A.Q-1230A.R) implemented in ND 1000A and VNE 1230H.1 in ND
1000H. In FIG. 10C, VNEs 1230A.1-P are separate from each other in
the sense that they can receive packets from outside ND 1000A and
forward packets outside of ND 1000A; VNE 1230A.1 is coupled with
VNE 1230H.1, and thus they communicate packets between their
respective NDs; VNE 1230A.2-1230A.3 may optionally forward packets
between themselves without forwarding them outside of the ND 1000A;
and VNE 1230A.P may optionally be the first in a chain of VNEs that
includes VNE 1230A.Q followed by VNE 1230A.R (this is sometimes
referred to as dynamic service chaining, where each of the VNEs in
the series of VNEs provides a different service--e.g., one or more
layer 4-7 network services). While FIG. 10C illustrates various
exemplary relationships between the VNEs, alternative embodiments
may support other relationships (e.g., more/fewer VNEs, more/fewer
dynamic service chains, multiple different dynamic service chains
with some common VNEs and some different VNEs).
[0086] The NDs of FIG. 10A, for example, may form part of the
Internet or a private network; and other electronic devices (not
shown; such as end user devices including workstations, laptops,
netbooks, tablets, palm tops, mobile phones, smartphones, phablets,
multimedia phones, Voice Over Internet Protocol (VOIP) phones,
terminals, portable media players, GPS units, wearable devices,
gaming systems, set-top boxes, Internet enabled household
appliances) may be coupled to the network (directly or through
other networks such as access networks) to communicate over the
network (e.g., the Internet or virtual private networks (VPNs)
overlaid on (e.g., tunneled through) the Internet) with each other
(directly or through servers) and/or access content and/or
services. Such content and/or services are typically provided by
one or more servers (not shown) belonging to a service/content
provider or one or more end user devices (not shown) participating
in a peer-to-peer (P2P) service, and may include, for example,
public webpages (e.g., free content, store fronts, search
services), private webpages (e.g., username/password accessed
webpages providing email services), and/or corporate networks over
VPNs. For instance, end user devices may be coupled (e.g., through
customer premise equipment coupled to an access network (wired or
wirelessly)) to edge NDs, which are coupled (e.g., through one or
more core NDs) to other edge NDs, which are coupled to electronic
devices acting as servers. However, through compute and storage
virtualization, one or more of the electronic devices operating as
the NDs in FIG. 10A may also host one or more such servers (e.g.,
in the case of the general purpose network device 1004, one or more
of the software instances 1062A-R may operate as servers; the same
would be true for the hybrid network device 1006; in the case of
the special-purpose network device 1002, one or more such servers
could also be run on a virtualization layer executed by the
processor(s) 1012); in which case the servers are said to be
co-located with the VNEs of that ND.
[0087] A virtual network is a logical abstraction of a physical
network (such as that in FIG. 10A) that provides network services
(e.g., L2 and/or L3 services). A virtual network can be implemented
as an overlay network (sometimes referred to as a network
virtualization overlay) that provides network services (e.g., layer
2 (L2, data link layer) and/or layer 3 (L3, network layer)
services) over an underlay network (e.g., an L3 network, such as an
Internet Protocol (IP) network that uses tunnels (e.g., generic
routing encapsulation (GRE), layer 2 tunneling protocol (L2TP),
IPSec) to create the overlay network).
[0088] A network virtualization edge (NVE) sits at the edge of the
underlay network and participates in implementing the network
virtualization; the network-facing side of the NVE uses the
underlay network to tunnel frames to and from other NVEs; the
outward-facing side of the NVE sends and receives data to and from
systems outside the network. A virtual network instance (VNI) is a
specific instance of a virtual network on an NVE (e.g., a NE/VNE on
an ND, a part of a NE/VNE on a ND where that NE/VNE is divided into
multiple VNEs through emulation); one or more VNIs can be
instantiated on an NVE (e.g., as different VNEs on an ND). A
virtual access point (VAP) is a logical connection point on the NVE
for connecting external systems to a virtual network; a VAP can be
physical or virtual ports identified through logical interface
identifiers (e.g., a VLAN ID).
[0089] Examples of network services include: 1) an Ethernet LAN
emulation service (an Ethernet-based multipoint service) in which
external systems are interconnected across the network by a LAN
environment over the underlay network (e.g., an NVE provides
separate L2 VNIs (virtual switching instances) for different such
virtual networks, and L3 (e.g., IP/MPLS) tunneling encapsulation
across the underlay network); and 2) a virtualized IP forwarding
service (similar to IETF IP VPN (e.g., Border Gateway Protocol
(BGP)/MPLS IPVPN) from a service definition perspective) in which
external systems are interconnected across the network by an L3
environment over the underlay network (e.g., an NVE provides
separate L3 VNIs (forwarding and routing instances) for different
such virtual networks, and L3 (e.g., IP/MPLS) tunneling
encapsulation across the underlay network)). Network services may
also include quality of service capabilities (e.g., traffic
classification marking, traffic conditioning and scheduling),
security capabilities (e.g., filters to protect customer premises
from network--originated attacks, to avoid malformed route
announcements), and management capabilities (e.g., full detection
and processing).
[0090] FIG. 10D illustrates a network with a single network element
on each of the NDs of FIG. 10A, and within this straight forward
approach contrasts a traditional distributed approach (commonly
used by traditional routers) with a centralized approach for
maintaining reachability and forwarding information (also called
network control), according to some embodiments of the invention.
Specifically, FIG. 10D illustrates network elements (NEs) 1230A-H
with the same connectivity as the NDs 1000A-H of FIG. 10A.
[0091] FIG. 10D illustrates that the distributed approach 1232
distributes responsibility for generating the reachability and
forwarding information across the NEs 1230A-H; in other words, the
process of neighbor discovery and topology discovery is
distributed.
[0092] For example, where the special-purpose network device 1002
is used, the control communication and configuration module(s)
1032A-R of the ND control plane 1024 typically include a
reachability and forwarding information module to implement one or
more routing protocols (e.g., an exterior gateway protocol such as
Border Gateway Protocol (BGP), Interior Gateway Protocol(s) (IGP)
(e.g., Open Shortest Path First (OSPF), Intermediate System to
Intermediate System (IS-IS), Routing Information Protocol (RIP),
Label Distribution Protocol (LDP), Resource Reservation Protocol
(RSVP) (including RSVP-Traffic Engineering (TE): Extensions to RSVP
for LSP Tunnels and Generalized Multi-Protocol Label Switching
(GMPLS) Signaling RSVP-TE)) that communicate with other NEs to
exchange routes, and then selects those routes based on one or more
routing metrics. Thus, the NEs 1230A-H (e.g., the processor(s) 1012
executing the control communication and configuration module(s)
1032A-R) perform their responsibility for participating in
controlling how data (e.g., packets) is to be routed (e.g., the
next hop for the data and the outgoing physical NI for that data)
by distributively determining the reachability within the network
and calculating their respective forwarding information. Routes and
adjacencies are stored in one or more routing structures (e.g.,
Routing Information Base (RIB), Label Information Base (LIB), one
or more adjacency structures) on the ND control plane 1024. The ND
control plane 1024 programs the ND forwarding plane 1026 with
information (e.g., adjacency and route information) based on the
routing structure(s). For example, the ND control plane 1024
programs the adjacency and route information into one or more
forwarding table(s) 1034A-R (e.g., Forwarding Information Base
(FIB), Label Forwarding Information Base (LFIB), and one or more
adjacency structures) on the ND forwarding plane 1026. For layer 2
forwarding, the ND can store one or more bridging tables that are
used to forward data based on the layer 2 information in that data.
While the above example uses the special-purpose network device
1002, the same distributed approach 1232 can be implemented on the
general-purpose network device 1004 and the hybrid network device
1006.
[0093] FIG. 10D illustrates that a centralized approach 1234 (also
known as software defined networking (SDN)) that decouples the
system that makes decisions about where traffic is sent from the
underlying systems that forwards traffic to the selected
destination. The illustrated centralized approach 1234 has the
responsibility for the generation of reachability and forwarding
information in a centralized control plane 1236 (sometimes referred
to as an SDN control module, controller, network controller,
OpenFlow controller, SDN controller, control plane node, network
virtualization authority, or management control entity), and thus
the process of neighbor discovery and topology discovery is
centralized. The centralized control plane 1236 has a south bound
interface 1082 with a user plane 1080 (sometime referred to the
infrastructure layer, network forwarding plane, or forwarding plane
(which should not be confused with a ND forwarding plane)) that
includes the NEs 1230A-H (sometimes referred to as switches,
forwarding elements, user plane elements, or nodes). The
centralized control plane 1236 includes a network controller 1238,
which includes a centralized reachability and forwarding
information module 1239 that determines the reachability within the
network and distributes the forwarding information to the NEs
1230A-H of the user plane 1080 over the south bound interface 1082
(which may use the OpenFlow protocol). Thus, the network
intelligence is centralized in the centralized control plane 1236
executing on electronic devices that are typically separate from
the NDs. In one embodiment, the network controller 1238 may include
an ILNP breakout component 1081 that when executed by the network
controller 1238, causes the network controller 1238 to perform
operations of one or more embodiments described herein above.
[0094] For example, where the special-purpose network device 1002
is used in the user plane 1080, each of the control communication
and configuration module(s) 1032A-R of the ND control plane 1024
typically include a control agent that provides the VNE side of the
south bound interface 1082. In this case, the ND control plane 1024
(the processor(s) 1012 executing the control communication and
configuration module(s) 1032A-R) performs its responsibility for
participating in controlling how data (e.g., packets) is to be
routed (e.g., the next hop for the data and the outgoing physical
NI for that data) through the control agent communicating with the
centralized control plane 1236 to receive the forwarding
information (and in some cases, the reachability information) from
the centralized reachability and forwarding information module 1239
(it should be understood that in some embodiments of the invention,
the control communication and configuration module(s) 1032A-R, in
addition to communicating with the centralized control plane 1236,
may also play some role in determining reachability and/or
calculating forwarding information--albeit less so than in the case
of a distributed approach; such embodiments are generally
considered to fall under the centralized approach 1234, but may
also be considered a hybrid approach).
[0095] While the above example uses the special-purpose network
device 1002, the same centralized approach 1234 can be implemented
with the general purpose network device 1004 (e.g., each of the VNE
1060A-R performs its responsibility for controlling how data (e.g.,
packets) is to be routed (e.g., the next hop for the data and the
outgoing physical NI for that data) by communicating with the
centralized control plane 1236 to receive the forwarding
information (and in some cases, the reachability information) from
the centralized reachability and forwarding information module
1239; it should be understood that in some embodiments of the
invention, the VNEs 1060A-R, in addition to communicating with the
centralized control plane 1236, may also play some role in
determining reachability and/or calculating forwarding
information--albeit less so than in the case of a distributed
approach) and the hybrid network device 1006. In fact, the use of
SDN techniques can enhance the NFV techniques typically used in the
general-purpose network device 1004 or hybrid network device 1006
implementations as NFV is able to support SDN by providing an
infrastructure upon which the SDN software can be run, and NFV and
SDN both aim to make use of commodity server hardware and physical
switches.
[0096] FIG. 10D also shows that the centralized control plane 1236
has a north bound interface 1084 to an application layer 1086, in
which resides application(s) 1088. The centralized control plane
1236 has the ability to form virtual networks 1092 (sometimes
referred to as a logical forwarding plane, network services, or
overlay networks (with the NEs 1230A-H of the user plane 1080 being
the underlay network)) for the application(s) 1088. Thus, the
centralized control plane 1236 maintains a global view of all NDs
and configured NEs/VNEs, and it maps the virtual networks to the
underlying NDs efficiently (including maintaining these mappings as
the physical network changes either through hardware (ND, link, or
ND component) failure, addition, or removal).
[0097] While FIG. 10D shows the distributed approach 1232 separate
from the centralized approach 1234, the effort of network control
may be distributed differently or the two combined in certain
embodiments of the invention. For example: 1) embodiments may
generally use the centralized approach (SDN) 1234, but have certain
functions delegated to the NEs (e.g., the distributed approach may
be used to implement one or more of fault monitoring, performance
monitoring, protection switching, and primitives for neighbor
and/or topology discovery); or 2) embodiments of the invention may
perform neighbor discovery and topology discovery via both the
centralized control plane and the distributed protocols, and the
results compared to raise exceptions where they do not agree. Such
embodiments are generally considered to fall under the centralized
approach 1234 but may also be considered a hybrid approach.
[0098] While FIG. 10D illustrates the simple case where each of the
NDs 1000A-H implements a single NE 1230A-H, it should be understood
that the network control approaches described with reference to
FIG. 10D also work for networks where one or more of the NDs
1000A-H implement multiple VNEs (e.g., VNEs 1030A-R, VNEs 1060A-R,
those in the hybrid network device 1006). Alternatively or in
addition, the network controller 1238 may also emulate the
implementation of multiple VNEs in a single ND. Specifically,
instead of (or in addition to) implementing multiple VNEs in a
single ND, the network controller 1238 may present the
implementation of a VNE/NE in a single ND as multiple VNEs in the
virtual networks 1092 (all in the same one of the virtual
network(s) 1092, each in different ones of the virtual network(s)
1092, or some combination). For example, the network controller
1238 may cause an ND to implement a single VNE (a NE) in the
underlay network, and then logically divide up the resources of
that NE within the centralized control plane 1236 to present
different VNEs in the virtual network(s) 1092 (where these
different VNEs in the overlay networks are sharing the resources of
the single VNE/NE implementation on the ND in the underlay
network).
[0099] On the other hand, FIGS. 10E and 10F respectively illustrate
exemplary abstractions of NEs and VNEs that the network controller
1238 may present as part of different ones of the virtual networks
1092. FIG. 10E illustrates the simple case of where each of the NDs
1000A-H implements a single NE 1230A-H (see FIG. 10D), but the
centralized control plane 1236 has abstracted multiple of the NEs
in different NDs (the NEs 1230A-C and G-H) into (to represent) a
single NE 12301 in one of the virtual network(s) 1092 of FIG. 10D,
according to some embodiments of the invention. FIG. 10E shows that
in this virtual network, the NE 12301 is coupled to NE 1230D and
1230F, which are both still coupled to NE 1230E.
[0100] FIG. 10F illustrates a case where multiple VNEs (VNE 1230A.1
and VNE 1230H.1) are implemented on different NDs (ND 1000A and ND
1000H) and are coupled to each other, and where the centralized
control plane 1236 has abstracted these multiple VNEs such that
they appear as a single VNE 1230T within one of the virtual
networks 1092 of FIG. 10D, according to some embodiments of the
invention. Thus, the abstraction of a NE or VNE can span multiple
NDs.
[0101] While some embodiments of the invention implement the
centralized control plane 1236 as a single entity (e.g., a single
instance of software running on a single electronic device),
alternative embodiments may spread the functionality across
multiple entities for redundancy and/or scalability purposes (e.g.,
multiple instances of software running on different electronic
devices).
[0102] Similar to the network device implementations, the
electronic device(s) running the centralized control plane 1236,
and thus the network controller 1238 including the centralized
reachability and forwarding information module 1239, may be
implemented a variety of ways (e.g., a special purpose device, a
general-purpose (e.g., COTS) device, or hybrid device). These
electronic device(s) would similarly include processor(s), a set or
one or more physical NIs, and a non-transitory machine-readable
storage medium having stored thereon the centralized control plane
software. For instance, FIG. 11 illustrates, a general-purpose
control plane device 1104 including hardware 1140 comprising a set
of one or more processor(s) 1142 (which are often COTS processors)
and physical NIs 1146, as well as non-transitory machine-readable
storage media 1148 having stored therein centralized control plane
(CCP) software 1150 and an ILNP breakout component 1151.
[0103] In embodiments that use compute virtualization, the
processor(s) 1142 typically execute software to instantiate a
virtualization layer 1154 (e.g., in one embodiment the
virtualization layer 1154 represents the kernel of an operating
system (or a shim executing on a base operating system) that allows
for the creation of multiple instances 1162A-R called software
containers (representing separate user spaces and also called
virtualization engines, virtual private servers, or jails) that may
each be used to execute a set of one or more applications; in
another embodiment the virtualization layer 1154 represents a
hypervisor (sometimes referred to as a virtual machine monitor
(VMM)) or a hypervisor executing on top of a host operating system,
and an application is run on top of a guest operating system within
an instance 1162A-R called a virtual machine (which in some cases
may be considered a tightly isolated form of software container)
that is run by the hypervisor; in another embodiment, an
application is implemented as a unikernel, which can be generated
by compiling directly with an application only a limited set of
libraries (e.g., from a library operating system (LibOS) including
drivers/libraries of OS services) that provide the particular OS
services needed by the application, and the unikernel can run
directly on hardware 1140, directly on a hypervisor represented by
virtualization layer 1154 (in which case the unikernel is sometimes
described as running within a LibOS virtual machine), or in a
software container represented by one of instances 1162A-R). Again,
in embodiments where compute virtualization is used, during
operation an instance of the CCP software 1150 (illustrated as CCP
instance 1176A) is executed (e.g., within the instance 1162A) on
the virtualization layer 1154. In embodiments where compute
virtualization is not used, the CCP instance 1176A is executed, as
a unikernel or on top of a host operating system, on the "bare
metal" general purpose control plane device 1104. The instantiation
of the CCP instance 1176A, as well as the virtualization layer 1154
and instances 1162A-R if implemented, are collectively referred to
as software instance(s) 1152.
[0104] In some embodiments, the CCP instance 1176A includes a
network controller instance 1178. The network controller instance
1178 includes a centralized reachability and forwarding information
module instance 1179 (which is a middleware layer providing the
context of the network controller 1238 to the operating system and
communicating with the various NEs), and an CCP application layer
1180 (sometimes referred to as an application layer) over the
middleware layer (providing the intelligence required for various
network operations such as protocols, network situational
awareness, and user--interfaces). At a more abstract level, this
CCP application layer 1180 within the centralized control plane
1236 works with virtual network view(s) (logical view(s) of the
network) and the middleware layer provides the conversion from the
virtual networks to the physical view.
[0105] The ILNP breakout component 1151 can be executed by hardware
1140 to perform operations of one or more embodiments of the
present invention as part of software instances 1152.
[0106] The centralized control plane 1236 transmits relevant
messages to the user plane 1080 based on CCP application layer 1180
calculations and middleware layer mapping for each flow. A flow may
be defined as a set of packets whose headers match a given pattern
of bits; in this sense, traditional IP forwarding is also
flow-based forwarding where the flows are defined by the
destination IP address for example; however, in other
implementations, the given pattern of bits used for a flow
definition may include more fields (e.g., 10 or more) in the packet
headers. Different NDs/NEs/VNEs of the user plane 1080 may receive
different messages, and thus different forwarding information. The
user plane 1080 processes these messages and programs the
appropriate flow information and corresponding actions in the
forwarding tables (sometime referred to as flow tables) of the
appropriate NE/VNEs, and then the NEs/VNEs map incoming packets to
flows represented in the forwarding tables and forward packets
based on the matches in the forwarding tables.
[0107] Standards such as OpenFlow define the protocols used for the
messages, as well as a model for processing the packets. The model
for processing packets includes header parsing, packet
classification, and making forwarding decisions. Header parsing
describes how to interpret a packet based upon a well-known set of
protocols. Some protocol fields are used to build a match structure
(or key) that will be used in packet classification (e.g., a first
key field could be a source media access control (MAC) address, and
a second key field could be a destination MAC address).
[0108] Packet classification involves executing a lookup in memory
to classify the packet by determining which entry (also referred to
as a forwarding table entry or flow entry) in the forwarding tables
best matches the packet based upon the match structure, or key, of
the forwarding table entries. It is possible that many flows
represented in the forwarding table entries can correspond/match to
a packet; in this case the system is typically configured to
determine one forwarding table entry from the many according to a
defined scheme (e.g., selecting a first forwarding table entry that
is matched). Forwarding table entries include both a specific set
of match criteria (a set of values or wildcards, or an indication
of what portions of a packet should be compared to a particular
value/values/wildcards, as defined by the matching
capabilities--for specific fields in the packet header, or for some
other packet content), and a set of one or more actions for the
user plane to take on receiving a matching packet. For example, an
action may be to push a header onto the packet, for the packet
using a particular port, flood the packet, or simply drop the
packet. Thus, a forwarding table entry for IPv4/IPv6 packets with a
particular transmission control protocol (TCP) destination port
could contain an action specifying that these packets should be
dropped.
[0109] Making forwarding decisions and performing actions occurs,
based upon the forwarding table entry identified during packet
classification, by executing the set of actions identified in the
matched forwarding table entry on the packet.
[0110] However, when an unknown packet (for example, a "missed
packet" or a "match-miss" as used in OpenFlow parlance) arrives at
the user plane 1080, the packet (or a subset of the packet header
and content) is typically forwarded to the centralized control
plane 1236. The centralized control plane 1236 will then program
forwarding table entries into the user plane 1080 to accommodate
packets belonging to the flow of the unknown packet. Once a
specific forwarding table entry has been programmed into the user
plane 1080 by the centralized control plane 1236, the next packet
with matching credentials will match that forwarding table entry
and take the set of actions associated with that matched entry.
[0111] A network interface (NI) may be physical or virtual; and in
the context of IP, an interface address is an IP address assigned
to a NI, be it a physical NI or virtual NI. A virtual NI may be
associated with a physical NI, with another virtual interface, or
stand on its own (e.g., a loopback interface, a point-to-point
protocol interface). A NI (physical or virtual) may be numbered (a
NI with an IP address) or unnumbered (a NI without an IP address).
A loopback interface (and its loopback address) is a specific type
of virtual NI (and IP address) of a NE/VNE (physical or virtual)
often used for management purposes; where such an IP address is
referred to as the nodal loopback address. The IP address(es)
assigned to the NI(s) of a ND are referred to as IP addresses of
that ND; at a more granular level, the IP address(es) assigned to
NI(s) assigned to a NE/VNE implemented on a ND can be referred to
as IP addresses of that NE/VNE.
[0112] Some portions of the preceding detailed descriptions have
been presented in terms of algorithms and symbolic representations
of transactions on data bits within a computer memory. These
algorithmic descriptions and representations are the ways used by
those skilled in the data processing arts to most effectively
convey the substance of their work to others skilled in the art. An
algorithm is here, and generally, conceived to be a self-consistent
sequence of transactions leading to a desired result. The
transactions are those requiring physical manipulations of physical
quantities. Usually, though not necessarily, these quantities take
the form of electrical or magnetic signals capable of being stored,
transferred, combined, compared, and otherwise manipulated. It has
proven convenient at times, principally for reasons of common
usage, to refer to these signals as bits, values, elements,
symbols, characters, terms, numbers, or the like.
[0113] It should be borne in mind, however, that all of these and
similar terms are to be associated with the appropriate physical
quantities and are merely convenient labels applied to these
quantities. Unless specifically stated otherwise as apparent from
the above discussion, it is appreciated that throughout the
description, discussions utilizing terms such as "processing" or
"computing" or "calculating" or "determining" or "displaying" or
the like, refer to the action and processes of a computer system,
or similar electronic computing device, that manipulates and
transforms data represented as physical (electronic) quantities
within the computer system's registers and memories into other data
similarly represented as physical quantities within the computer
system memories or registers or other such information storage,
transmission or display devices.
[0114] The algorithms and displays presented herein are not
inherently related to any particular computer or other apparatus.
Various general-purpose systems may be used with programs in
accordance with the teachings herein, or it may prove convenient to
construct more specialized apparatus to perform the required method
transactions. The required structure for a variety of these systems
will appear from the description above. In addition, embodiments of
the present invention are not described with reference to any
particular programming language. It will be appreciated that a
variety of programming languages may be used to implement the
teachings of embodiments of the invention as described herein.
[0115] An embodiment of the invention may be an article of
manufacture in which a non-transitory machine-readable medium (such
as microelectronic memory) has stored thereon instructions which
program one or more data processing components (generically
referred to here as a "processor") to perform the operations
described above. In other embodiments, some of these operations
might be performed by specific hardware components that contain
hardwired logic (e.g., dedicated digital filter blocks and state
machines). Those operations might alternatively be performed by any
combination of programmed data processing components and fixed
hardwired circuit components.
[0116] In the foregoing specification, embodiments of the invention
have been described with reference to specific exemplary
embodiments thereof. It will be evident that various modifications
may be made thereto without departing from the broader spirit and
scope of the invention as set forth in the following claims. The
specification and drawings are, accordingly, to be regarded in an
illustrative sense rather than a restrictive sense.
[0117] Throughout the description, embodiments of the present
invention have been presented through flow diagrams. It will be
appreciated that the order of transactions and transactions
described in these flow diagrams are only intended for illustrative
purposes and not intended as a limitation of the present invention.
One having ordinary skill in the art would recognize that
variations can be made to the flow diagrams without departing from
the broader spirit and scope of the invention as set forth in the
following claims.
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