U.S. patent application number 12/619055 was filed with the patent office on 2010-03-04 for mobile ip addressing.
This patent application is currently assigned to QUALCOMM Incorporated. Invention is credited to Gavin Bernard Horn, Nikhil Jain.
Application Number | 20100054190 12/619055 |
Document ID | / |
Family ID | 38322019 |
Filed Date | 2010-03-04 |
United States Patent
Application |
20100054190 |
Kind Code |
A1 |
Jain; Nikhil ; et
al. |
March 4, 2010 |
MOBILE IP ADDRESSING
Abstract
A system and method are provided for mobile Internet Protocol
(IP) addressing, in a multi-mode wireless communications access
terminal (AT). The method provides an AT with an IP address (ATA),
and a care-of-address (CoA) in each of a plurality of networks. In
one aspect, the AT selects a first network for transmission, from
the plurality of networks. The AT sends an IP packet to a
correspondent node (CN) via a first mobile node (MN) external
device. Regardless of the network selected, the AT is able to use
the ATA as a source address. Sending the IP packet to the CN may
include creating a tunnel between the first MN and the HA. The IP
packet is sent to the HA using the first CoA as a tunnel source
address, and the HA sends the IP packet to the CN using the ATA as
the source address.
Inventors: |
Jain; Nikhil; (San Diego,
CA) ; Horn; Gavin Bernard; (La Jolla, CA) |
Correspondence
Address: |
QUALCOMM INCORPORATED
5775 MOREHOUSE DR.
SAN DIEGO
CA
92121
US
|
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
38322019 |
Appl. No.: |
12/619055 |
Filed: |
November 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11347506 |
Feb 2, 2006 |
7633898 |
|
|
12619055 |
|
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|
|
Current U.S.
Class: |
370/328 |
Current CPC
Class: |
H04W 36/14 20130101;
H04W 8/26 20130101; H04W 36/0011 20130101; H04W 80/04 20130101;
H04W 8/08 20130101; H04L 69/14 20130101 |
Class at
Publication: |
370/328 |
International
Class: |
H04W 40/00 20090101
H04W040/00 |
Claims
1. In a multi-mode wireless communications access terminal (AT), a
method for mobile Internet Protocol (IP) addressing, the method
comprising: providing an AT having an IP address (ATA) and a
care-of-address (CoA) in each of a plurality of networks; from the
plurality of networks, selecting a first network for transmission;
and, sending an IP packet to a correspondent node (CN) via a first
mobile node (MN) external device, using the ATA as a source
address.
2. The method of claim 1 further comprising: selecting a second
network for transmission; and, sending an IP packet to the CN via a
second MN external device using the ATA as the source address.
3. The method of claim 1 further comprising: selecting the second
network for transmission, in addition to the first network; and,
sending IP packets to the CN via the first MN with a first CoA, and
via a second MN with a second CoA, using the ATA as the source
address.
4. The method of claim 1 wherein providing the AT having the ATA
and the CoA in each of a plurality of networks includes creating a
tunnel between the first MN and the HA; wherein sending the IP
packet to the CN includes: sending the IP packet to the HA using
the first CoA as a tunnel source address; and sending the IP packet
from the HA to the CN using the ATA as the source address.
5. The method of claim 4 further comprising: registering the CoAs
with the HA, from a source selected from the group consisting of
the AT, the MN, and a combination of the AT and the MN.
6. A multi-mode wireless communications access terminal (AT) system
for sending Internet Protocol (IP) packets using mobile IP (MIP)
addressing, the system comprising: an AT comprising: a plurality of
communication subsystems having wireless transceivers for
communicating with external device mobile units (MNs) in a
corresponding plurality of networks; and, a MIP addressing module
having communication subsystem interfaces and an AT IP address
(ATA) cross-referenced to a care-of-address (CoA) for each of the
plurality of MNs, the MIP addressing module selecting a first
network for transmission, and sending an IP packet to a
correspondent node (CN) using the ATA as the source address, via a
first MN.
7. The system of claim 6 wherein the AT MIP addressing module
selects a second subsystem for transmission, and sends an IP packet
to the CN using the ATA as the source address, via a second MN.
8. The system of claim 6 wherein the AT MIP addressing module
selects the second subsystem for transmission, in addition to the
first subsystem, and sends IP packets to the CN using the ATA as
the destination address, via the first MN associated with the first
network, and via a second MN associated with a second network.
9. The system of claim 6 further comprising: a first MN having a
first network interface for receiving the IP packet from the AT
with the ATA listed as the source address, the first MN having a
tunnel interface for sending the IP packet, using a first CoA as
the tunnel source address; and a home agent (HA) having a tunnel
interface for receiving the IP packet from the first MN, and a
network interface to sending the IP packet to the CN with the ATA
listed as the source address.
10. The system of claim 9 wherein the CoAs are registered with the
HA, from a source selected from the group consisting of the AT, the
MN, and a combination of the AT and the MN.
11. A multi-mode wireless communications access terminal (AT)
processing device for sending Internet Protocol (IP) packets using
mobile IP (MIP) addressing, the processing device comprising:
interfaces for a plurality of communication subsystems wirelessly
communicating with external device mobile units (MNs) in a
corresponding plurality of networks; a memory for storing an AT IP
address (ATA); and, a network address selector for sending an IP
packet to a correspondent node (CN) using the ATA as the source
address, via a first MN with a first care-of-address (CoA).
12. The processing device of claim 11 wherein the network address
selector receives an IP packet from the CN with the ATA listed as
the destination address, via the first MN.
13. A multi-mode wireless communications access terminal (AT) with
means for sending Internet Protocol (IP) packets using mobile IP
(MIP) addressing, the AT comprising: means for wirelessly
communicating with external device mobile units (MNs) in a
plurality of networks; and, means for network selection, having an
AT IP address (ATA) cross-referenced to a care-of-address (CoA) for
each of the plurality of MNs, the network selection means selecting
a first network for transmission and sending an IP packet to a
correspondent node (CN) using the ATA as the source address, via a
first MN.
14. The AT of claim 13 wherein the network selection means receives
an IP packet from the CN with the ATA listed as the destination
address, via the first MN.
15. In a multi-mode wireless communications access terminal (AT), a
signal bearing medium tangibly embodying a program of
machine-readable instructions executable by a digital processing
apparatus to perform operations for mobile Internet Protocol (IP)
addressing, the operations comprising: providing an AT having an IP
address (ATA) and a care-of-address (CoA) in each of a plurality of
networks; from the plurality of networks, selecting a first network
for transmission; and, sending an IP packet to a correspondent node
(CN) via a first mobile node (MN) external device, using the ATA as
a source address.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. patent
application Ser. No. 11/347,506, filed Feb. 2, 2006 and titled
MOBILE IP ADDRESSING, which is hereby expressly incorporated by
reference.
BACKGROUND
[0002] 1. Field
[0003] The present invention generally relates to wireless
communications and, more particularly, to a mobile Internet
Protocol (IP) system and method for addressing a wireless
transponder access terminal (AT).
[0004] 2. Background
[0005] Traffic on the Internet is growing exponentially due to an
increasing number of subscribers and the introduction of new
applications. Wide area wireless networks are also experiencing
rapid subscriber growth. Currently, there are many efforts underway
to provide data services on wireless access networks.
[0006] To facilitate data services in mobile wireless
telecommunication systems, it is desirable to allow mobile wireless
nodes to change their link-layer point of network attachment
without reassigning a new network address. According to current
data network telecommunication standards for mobile equipment in
general (e.g., the "Mobile IP" standards promulgated by the
Internet Engineering Task Force (IETF) or the General Packet Radio
Service (GPRS) standards proposed by the European Telecommunication
Standards Institute (ETSI)), one way to provide the desired network
address transparency is to employ "mobility agents." These are
network routing nodes that route communication content on behalf of
mobile nodes as they move around the network. For example,
according to the IETF Mobile IP standards, a mobile node's mobility
agents may consist of a "home agent" routing node and may also
include a "foreign agent" routing node. The home agent is a routing
node in the mobile node's sub-network that maintains a network
interface on the link indicated by the mobile node's "home
address," which is a network address intended to remain assigned to
the mobile node for an extended time period. When the mobile node
is away from its home sub-network, the home agent intercepts
communication content bound for the mobile node's home address and
tunnels it for delivery to a "care-of-address" assigned to the
mobile node, when the mobile node registers on a foreign
sub-network. The care-of address may be the address of a foreign
agent routing node in the foreign sub-network.
[0007] Correspondent nodes wishing to communicate with a
foreign-registered mobile node are able to address their
communication content to the mobile node's home address.
Transparently, the communication content is tunneled to the mobile
node's care-of-address and delivered to the mobile node on the
foreign sub-network. Normal routing may be used for sending return
communication content from the mobile node to the correspondent
node.
[0008] The above-mentioned routing mechanism can be used for mobile
wireless nodes connected to a foreign sub-network via an air
interface. However, a problem may arise if the mobile wireless node
is being actively transported while communicating over the data
network, and a call handoff is required from one radio base station
to another. In that case, the old base station may be linked to one
care-of-address, while the new base station is linked to another
care-of-address. Call handoff then requires that the communication
tunneling endpoint be transferred from the old care-of-address to
the new care-of-address.
[0009] Further, in some cellular telephony architectures a
care-of-address endpoint located in the core network is utilized as
the addressed communication, e.g. target Internet Protocol Address,
for data communication with a wireless communication apparatus or
terminal. In some instances, the endpoint may be a packet data
service node (PDSN), a base station controller (BSC), or the like.
A handoff between PDSN endpoints may be required to maintain a
minimum level of communications with the mobile wireless node, for
instance due to conditions in the core network such as congestion
or latency to the mobile wireless node. A PDSN handoff then
requires that the communication tunneling endpoint be transferred
from the care-of-address of the old PDSN, to the care-of-address of
the new PDSN.
[0010] Transferring the tunneling endpoint of the care-of-address
may create gaps that interrupt the timely delivery of call content,
or result in out-of-order delivery of content, both of which can
degrade communication quality, particularly for voice telephony.
Such gaps arise from the inability of the data network to
coordinate well with the air interface so as to determine the exact
time of handoff. Delays can occur between the point of handoff and
the point at which the home agent begins routing communication
content to the new care-of-address.
[0011] It would be advantageous if a telecommunication system
serving mobile wireless access terminals could provide improved
call handoff without loss of communication content. It would also
be advantageous if the tunneling endpoint care-of address could be
maintaining without transfers or handoffs.
SUMMARY
[0012] Multi-mode wireless communications access terminals (ATs),
devices capable of communicating in different types of networks,
are becoming more common. For example, an AT may be capable of
communicating in both an IEEE 802.11 network and a CDMA cellular
network. Conventionally, such an AT has a different IP address for
each network. Network handoffs are complicated by the fact that the
networks have different geographic coverage areas and quality of
service (QoS) capabilities. Further, although different networks
may all be connected to the Internet, communications between
networks is still an evolving issue.
[0013] The instant invention uses a home agent (HA) to manage
session continuity for multi-mode AT communications, where each
mode is associated with a different network. The HA
cross-references an AT's mobile IP (MIP) address with a
care-of-address (CoA) in each network. Thus, the HA is able to
direct IP packets via a particular network on a packet-by-packet
basis, or send duplicate packets via multiple networks for improved
reliability.
[0014] Accordingly, a method is provided for mobile IP addressing,
in a multi-mode wireless communications AT. The method provides an
AT with an IP address (ATA), and a CoA in each of a plurality of
networks. In one aspect, the AT selects a first network for
transmission, from the plurality of networks. The AT sends an IP
packet to a correspondent node (CN) via a first mobile node (MN)
external device, and regardless of the network selected, the AT is
able to use the ATA as the source address in the packet header.
[0015] Sending the IP packet to the CN may include creating a
tunnel between the MN and the HA. The IP packet is sent to the HA
using the first CoA as a tunnel source address, and the HA removes
the tunnel header information and sends the IP packet to the CN
with the ATA as the source address.
[0016] In another aspect, the AT receives an IP packet from the CN
with the ATA listed as a destination address, via a MN external
device. Again, the ATA can be used as the destination address in
the IP packet header, regardless of the network selected. More
particularly, receiving an IP packet from the CN may include the CN
sending the IP packet to the HA, and the creation of a tunnel
between the HA and the MN. For example, the IP packet can be sent
to the first MN with a first CoA listed as a tunnel destination
address, and the first MN can remove the tunnel header information
and send the IP packet to the AT, with the ATA listed as the
destination address.
[0017] Additional details of the above-described method, and a
multi-mode wireless AT system for sending IP packets through the
use of MIP addressing are described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic block diagram of a multi-mode wireless
communications access terminal (AT) system for sending Internet
Protocol (IP) packets using mobile IP (MIP) addressing.
[0019] FIG. 2 is a schematic block diagram featuring a first
variation of the AT MIP addressing system of FIG. 1.
[0020] FIG. 3 is a schematic block diagram featuring a second
variation of the AT MIP addressing system of FIG. 1.
[0021] FIG. 4 is a diagram depicting the digital wrapper used for
transporting an IP packet from the AT to the CN.
[0022] FIG. 5 is a schematic block diagram of a multi-mode wireless
communications AT system for receiving IP packets using MIP
addressing.
[0023] FIG. 6 is a diagram depicting the digital wrapper used for
transporting an IP packet from the CN to the AT.
[0024] FIG. 7 is a diagram depicting TCP/IP protocol stack, as
modified for use with the present invention MIP addressing
system.
[0025] FIG. 8 is a diagram depicting a variation of the MIP
addressing protocol stack of FIG. 7.
[0026] FIG. 9 is a flowchart illustrating a method for MIP
addressing in a multi-mode wireless communications access AT.
[0027] FIG. 10 is a flowchart illustrating a variation in the
method for MIP addressing in a multi-mode wireless communications
AT.
[0028] FIG. 11 is a schematic block diagram featuring a third
variation of the multi-mode wireless communications AT of FIG.
1.
DETAILED DESCRIPTION
[0029] FIG. 1 is a schematic block diagram of a multi-mode wireless
communications access terminal (AT) system for sending Internet
Protocol (IP) packets using mobile IP (MIP) addressing. The system
100 comprises an AT 102. The access terminal may be referred to by
those skilled in the art as a handset, a wireless communications
device, user terminal, user equipment, mobile station, mobile unit,
subscriber station, subscriber unit, mobile radio, radio telephone,
wireless station, wireless device, or some other terminology. The
various concepts described throughout this disclosure are intended
to apply all wireless communication devices regardless of their
specific nomenclature. Since the AT is multi-mode, it includes a
plurality of communication subsystems having wireless transceivers
for communicating with external device mobile units (MNs) in a
corresponding plurality of networks. A first subsystem 104, for
communicating with a first network 106, and a second subsystem 108,
for communicating with a second network 110, are shown. However, it
should be understood that the AT 102 is not limited to any
particular number of subsystems. For example, the subsystems may be
capable of communicating with Ethernet, Bluetooth, IEEE 802.11,
IEEE 802.15, Code Division Multiple Access (CDMA) telephone, or
Global System for Mobile communications (GSM) telephone networks,
to name a few possible examples. The AT 102 is not limited to any
particular type of wireless communications, and in some aspects,
wired communications are supported.
[0030] A MIP addressing module 112 has communication subsystem
interfaces 114 and 116, connected to subsystems 104 and 108,
respectively. The MIP addressing module 112 has an AT IP address
(ATA) that is cross-referenced to a care-of-address (CoA) for each
of the plurality of MNs. As shown, the MIP addressing module 112
selects the first network 106 for transmission, and sends an IP
packet to a correspondent node (CN) 118. As explained below, the
MIP addressing module send the IP packet via a first MN 120, using
the ATA as the source address.
[0031] Alternately, the MIP addressing module 112 may be understood
to be a processing device, which can be enabled with a
microprocessor 150 and microprocessor executable instructions
stored in memory 152. In some aspects, some or all of the processor
steps can be enabled using a state machine or electronic circuitry.
In this case, the processing device 112 comprises interfaces 114
and 116 for a plurality of communication subsystems 104/108
wirelessly communicating with external device MNs 120/122 in a
corresponding plurality of networks 106/110. The memory 152 stores
the AT ATA. A network address selector 154 sends IP packets to CN
118 using the ATA as the source address, via the first MN 120 with
the first CoA (FIG. 1), the second MN 122 with the second CoA (FIG.
2), or a combination of the two MNs (FIG. 3).
[0032] FIG. 2 is a schematic block diagram featuring a first
variation of the AT MIP addressing system of FIG. 1. As shown, the
AT MIP addressing module 112 selects the second subsystem for
transmission 108, and sends an IP packet to the CN 118. The packet
is sent via a second MN 122 in the second network 110, via
interface 124, using the ATA as the source address.
[0033] FIG. 3 is a schematic block diagram featuring a second
variation of the AT MIP addressing system of FIG. 1. Here, the AT
MIP addressing module 112 selects the second subsystem 108 for
transmission, in addition to the first subsystem 104. The MIP
addressing module 112 sends IP packets to the CN 118 using the ATA
as the destination address. The packets are sent via the first MN
120 associated with the first network 106, and via the second MN
122 associated with a second network 110. FIG. 4 is a diagram
depicting the digital wrapper used for transporting an IP packet
from the AT 102 to the CN 118. Viewing both FIGS. 1 and 4, the
first MN 120 has a first network interface 130 (represented as an
antenna) for receiving the IP packet from the AT 102 with the ATA
listed as the source address. The first MN 120 has a tunnel
interface 132 for sending the IP packet, using a first CoA as the
tunnel source address. A home agent (HA) 134 has a tunnel interface
136 for receiving the IP packet from the first MN 120. The HA 134
has a network interface 138 to sending the IP packet to the CN 118,
with the ATA listed as the source address. It should be understood
that although the interface 130 and the first MN 120 are shown as a
common device, they need not necessarily be co-located. In other
aspects not shown, data can be communicated from the air interface
130 to the first MN 120 through a communication link. Further, the
interface 136 from the first MN and the interface 124 from the
second MN 122 (see FIG. 2) may be the same interface. Likewise, the
HA to CN interface 138 may also be the same, regardless of whether
the first or second network is used.
[0034] As shown, the HA 134 includes a memory 140 where the AT's
ATA is cross-referenced to each CoA. CoA1 is shown associated with
the first MN 120 in the first network 106. CoA2 is shown associated
with the second MN 122 in the second network 110. The CoAs may be
registered in the HA 134 by the AT 102, the MN (either first MN 102
or second MN 122), or a combination of the AT 102 and the
MN(s).
[0035] FIG. 5 is a schematic block diagram of a multi-mode wireless
communications AT system for receiving IP packets using MIP
addressing. The system 500 comprises AT 102, with the first
communication subsystem 104 and the second communication subsystem
108, as shown in FIG. 1. Again, the MIP addressing module 112 has
communication subsystem interfaces and an AT ATA cross-referenced
to CoAs for the first MN external device 120 and the second MN
external device 122. The MIP addressing module 112 receives an IP
packet from the CN 118, via the first MN 120. The IP packet lists
the ATA as the destination address, via the first MN 120.
[0036] As explained in the description of FIG. 1, the MIP
addressing module 112 may be understood as a microprocessor 150,
memory 152, and MIP addressing section 154. As explained above, the
MIP addressing module 112 comprises interfaces 114 and 116 for a
plurality of communication subsystems 104/108 wirelessly
communicating with external device MNs 120/122 in a corresponding
plurality of networks 106/110. The memory 152 stores the AT ATA. In
this aspect, the network address selector 154 receives IP packets
from CN 118 with the ATA listed as the destination address, via the
first MN 120, the second MN 122, or both MNs.
[0037] FIG. 11 is a schematic block diagram featuring a third
variation of the multi-mode wireless communications AT of FIG. 1.
The AT 1100 includes means for wirelessly communicating with
external device mobile units (MNs) in a plurality of networks. Two
wireless communication means 1102 and 1104 are shown, however, the
AT is not limited to any particular number. Also shown is a means
for network selection 1106. The network selection means 1106 has an
AT IP address (ATA) cross-referenced to a care-of-address (CoA) for
each of the plurality of MNs. MNs 120 and 122 are shown. The
network selection means 1106 selects a first network for
transmission (i.e., network 106), and sends an IP packet to CN 118
using the ATA as the source address, via the first MN 120. In
another aspect, the network selection means 1106 receives an IP
packet from the CN 118 with the ATA listed as the destination
address, via the first MN 120.
[0038] FIG. 6 is a diagram depicting the digital wrapper used for
transporting an IP packet from the CN 118 to the AT 102. Viewing
both FIGS. 5 and 6, the HA 134 has a network interface 138 for
receiving the IP packet from the CN 118, with the ATA listed as the
destination address. The HA 134 has a tunnel interface 136 for
sending the IP packet with the first CoA listed as the tunnel
destination address. The first MN 120 has a tunnel interface 132
for receiving the IP packet, and a network interface 130 for
sending the IP packet to the AT 102. The first MN 120 sends the IP
packet to the AT 102 with the ATA listed as the destination
address.
[0039] The network that is used for sending the IP packet to the AT
102 may be configured by a number of different elements, including
the AT 102, the HA 134, the first MN 120 (or second MN 122), or a
combination of the AT, HA and MN(s). If the HA 134 makes the
selection, a packet filter 142 may be configured to use selection
criteria such as the source address, destination address, source
port, destination port, type of service, protocol type, packet
size, traffic class, or flow label. Other criteria, well known by
those skilled in the art, could also be used in the design of the
packet filter 142.
[0040] Although not specifically shown in FIGS. 5 and 6, in other
aspects of the system, IP packets can be sent from the CN 118, to
the AT 102, using the second network 110, or both the first and
second networks. It should also be understood that although only
two networks, and two corresponding AT communication subsystems are
shown, the system 500 is not limited to any particular number of
networks or AT communication subsystems.
Functional Description
[0041] In IP networks, routing is based on stationary IP addresses,
just as a postal letter is delivered to the fixed address on the
envelope. A device on a network is reachable through normal IP
routing, using a network-assigned IP address. This fixed-address
scheme begins to break down when a device roams away from its home
network and is no longer reachable using normal IP routing, which
may result in an active session being terminated. Mobile IP was
created to enable users to keep the same IP address, while
traveling to a different network carrier, or using a different
technology, to ensure that sessions or connections are not
dropped.
[0042] Because the mobility functions of Mobile IP have been
conventionally performed at the network layer, rather than at the
physical layer, the AT can span different types of wireless and
wireline networks while maintaining connections and ongoing
applications. Remote login, remote printing, and file transfers are
some examples of applications where it is undesirable to interrupt
communications while an individual roams across network boundaries.
Also, certain network services, such as software licenses and
access privileges, are based on IP addresses. Changing these IP
addresses can compromise the network services.
[0043] FIG. 7 is a diagram depicting TCP/IP protocol stack, as
modified for use with the present invention MIP addressing system.
Conventionally, mobile stations (i.e., WLAN devices) have been
dependent upon Physical Media. For example, an IEEE 802.11b device
must undergo a re-association procedure when it acquires a new
access point (AP). As mentioned above, the Internet assumes the use
of static device locations and addresses. As a result, when a
conventional mobile device reconnects in a new location, a new IP
address must be obtained. Further, a new default router address and
DNS server address must be obtained. If the mobile station is a
computer, a change in IP address usually requires that the network
interface for the device be restarted. Typically, any previously
running applications using the network interface are likely to stop
working properly.
[0044] Conventional IP addresses are used for two purposes: host
identification and routing. With respect to the identification of a
host, the TCP/IP stack typically identifies the source IP address
as the endpoint. These addresses correspond to specific locations
on the Internet. MIP is a solution that is independent of the
Physical and data layers. MIP addressing creates a
location-independent identifier for an AT, while creating a new
type of location-dependent address. A permanent IP address, also
referred to herein as a home address or ATA is used to identify the
AT. Another address, which may change depending upon the location
of the AT, referred to herein as the CoA, is used for routing.
[0045] As described in the explanation of FIGS. 1 through 6, a
mobile node (MN) can be thought of as a device that maintains an
immediate link with the AT, even if the AT is roaming. However, it
should be understood that a roaming AT may acquire different MNs as
it roams through a network. Acquiring a new MN may require that the
AT obtain a new CoA. The AT communicates with a MN in each network,
and the CoA can be thought of as the intermediary address between
the HA and AT. Unlike conventional MIP, the MN of the present
invention system is also located in a device external to the AT. In
one aspect, there is a separate MN for each network interface used
by the AT.
[0046] The Home Agent is a router, typically located in the AT's
home network, which serves as the anchor point for communication
with the MN. The HA tunnels packets from a CN device on the
Internet, to the MN. Conventionally, a foreign agent is a router
that may function as the point of attachment for the Mobile Node
when it roams to a foreign network, delivering packets from the
Home Agent to the Mobile Node. However, since the MN of the present
invention system is external to the AT, and therefore, not
necessarily roaming, the functions previously associated with the
foreign agent are performed by the MN in the present invention.
[0047] The care-of-address is the termination point of the tunnel
in the Mobile Node. The Home Agent maintains an association between
the AT's ATA and its care-of address, which is the address of the
Mobile Node communicating with the AT. The AT is able to send and
receive packets using its home IP address, effectively maintaining
the appearance that it is always on its home network. Even when the
AT is roaming in foreign networks, its movements are transparent to
correspondent nodes.
[0048] The systems described in FIGS. 1 through 6 may be arranged
to support an arrangement of networks, where the AT is able to
communicate in different networks having complementary strengths.
For example, the AT may be registered with an HA for a number of
networks, to receive data simultaneously over multiple radio access
technologies (RAT), for the purpose of redundancy. Alternately, the
AT may use one network (i.e., a cellular network) for paging, and a
different network (i.e., a wireless LAN) for packet forwarding. In
one aspect, the HA manages the use of networks using a
predetermined policy. In a different aspect, the AT uses messaging
to manage network use, and to configure the HA and MN devices.
Further, the HA may also be configured to dynamically update how
and where packets are sent, based on data traffic received from the
AT. For example, paging through a first network may occur as a
result of data packets being received at the HA.
[0049] The AT may be configured for listening to only a first
network for paging. When a page is received, the AT may access the
network on which it was paged, access another network, or access
multiple networks simultaneously (for redundancy). The HA may be
configured differently, based on AT capabilities and policy, to
support each mode of access.
[0050] With respect to handoffs, the HA may be configured to
forward a packet to multiple RAT networks. A multi-mode AT may
simultaneously download from two RAT networks during handoff. The
AT may switch to a destination network, once the same packet is
received from both networks, or it may switch when it receives a
message from the HA in the data stream.
[0051] FIG. 8 is a diagram depicting a variation of the MIP
addressing protocol stack of FIG. 7. In this figure, a mobile node
(MN) is located at the AP. A MIP tunnel is created between the HA
and the AP (MN) in the first network. Although not specifically
shown, the second network has an equivalent protocol stack, with
the AT using the second network MAC/PHY access layers.
[0052] With respect to registration, different filter sets can be
defined for an AT, with a destination CoA associated with each
filter. That is, a different packet forwarding policy can be
configured for each filter. With respect to forwarding, MIP can be
used to manage the forwarding of packet flows during a connection.
In another aspect, a packet flow's behavior may be dynamically
updated based on data traffic received from the AT.
[0053] FIG. 9 is a flowchart illustrating a method for MIP
addressing in a multi-mode wireless communications access AT. In
combination with FIG. 5, the flowchart may represent a signal
bearing medium tangibly embodying a program of machine-readable
instructions executable by a digital processing apparatus to
perform operations for MIP addressing in a multi-mode wireless
communications AT. Although the method is depicted as a sequence of
numbered steps for clarity, the numbering does not necessarily
dictate the order of the steps. It should be understood that some
of these steps may be skipped, performed in parallel, or performed
without the requirement of maintaining a strict order of sequence.
The method starts at Step 900.
[0054] Step 902 provides an AT having an IP address (ATA) and a CoA
in each of a plurality of networks, see the explanation of FIG. 1
above. Step 904 selects a first network for transmission from the
plurality of networks. Step 906 sends an IP packet to a CN via a
first MN external device, using the ATA as a source address.
[0055] Alternately, Step 905 selects a second network for
transmission, and Step 908 sends an IP packet to the CN via a
second MN external device using the ATA as the source address. In
another aspect, Steps 904 and 905 are both preformed. That is, the
second network is selected for transmission, in addition to the
first network. Then, Step 906 and 908 are both performed.
[0056] In a different aspect, Step 902 includes creating a tunnel
between the first MN and the HA, and sending the IP packet to the
CN in Step 906 (or Step 908) includes substeps. Step 906a sends the
IP packet to the HA using the first CoA as a tunnel source address.
Step 906b sends the IP packet from the HA to the CN using the ATA
as the source address.
[0057] In one aspect Step 903 registers the CoAs with the HA, from
a source such as the AT, the MN(s), or a combination of the AT and
the MN(s).
[0058] FIG. 10 is a flowchart illustrating a variation in the
method for MIP addressing in a multi-mode wireless communications
AT. The method starts at Step 1000. Step 1002 provides an AT having
an IP address (ATA) and a CoA in each of a plurality of networks.
Step 1004 selects a first network from the plurality of networks.
Step 1006 receives an IP packet from a CN with the ATA listed as a
destination address, via a first MN external device.
[0059] In one aspect, Step 1002 creates a tunnel between the HA and
the first MN, and receiving an IP packet from the CN in Step 1006
includes substeps. Step 1006a sends the IP packet from the CN to
the HA. Step 1006b sends the IP packet to the first MN with a first
CoA listed as a tunnel destination address. Step 1006c sends the IP
packet from the first MN to the AT, with the ATA listed as the
destination address.
[0060] In one aspect, selecting the first network in Step 1004
includes selecting the first network from a source such as the AT,
the HA, the MN, and a combination of the AT, HA and MN. If the HA
selects the first network, it may use packet filter criteria such
as source address, destination address, source port, destination
port, type of service, protocol type, packet size, traffic class,
or flow label, to name a few examples.
[0061] In a different aspect, Step 1004 selects the first network
and a second network. A further step, Step 1005, receives a paging
message via a second MN associated with a second network, prior to
receiving the IP packet. Then, receiving the IP packet in Step 1006
includes accessing the first network in response to receiving the
paging message, and receiving the IP packet via the first
network.
[0062] In one aspect, Step 1004 selects the first network and the
second network, and receiving the IP packet from the CN in Step
1006 includes receiving IP packets via a second MN associated with
the second network, in addition to receiving IP packets via the
first MN associated with the first network. In a different aspect
Step 1008 sends an IP packet to an HA via the first network. Then,
in Step 1010 the HA ceases to forward IP packets on a second
network, in response to the AT sending the IP packet via the first
network in Step 1008. Alternately, the AT may send a redirect
message to the HA in Step 1008, and in Step 1010 the HA ceases to
forward IP packets on a second network in response to sending the
redirect message. That is, packets are received only via the
selected first network.
[0063] In another aspect, Step 1008 sends an IP packet to an HA via
the second MN associated with a second network. Step 1009 selects
the second network in response to the AT sending the IP packet, and
Step 1010 subsequently receives IP packets via the second MN.
[0064] A system and method have been described for using MIP
addressing in a wireless communications AT. Some examples of
specific protocols, network types, and signaling have been provided
to illustrate the invention. However, the invention is not limited
to merely these examples. Other variations and embodiment of the
invention will occur to those skilled in the art.
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