NETWORK-BASED MACRO MOBILITY IN CELLULAR NETWORKS USING AN EXTENDED ROUTING PROTOCOL

• US 20100177674A1
• Filed: 04/10/2009
• Published: 07/15/2010
• Est. Priority Date: 01/12/2009
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Aggarwal, Rahul
• Granted Patent: US 8,385,332 B2
• Time in Patent Office: Days
• US Class Current: 370/312
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/36 Backward learning
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 63/0272 Virtual private networks
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 76/12 Setup of transport tunnels
• CPC Class Codes: H04W 8/082 for traffic bypassing of mobility servers, e.g. location registers, home PLMNs or home agents
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A new architecture provides network-based mobility in cellular networks that is built on Internet Protocol (IP)/Multiprotocol Label Switching (MPLS) technologies, such as Virtual Private Local Area Network (LAN) Service (VPLS), the Border Gateway Protocol (BGP) and BGP MPLS Layer 3 Virtual Private Networks (VPNs). The architecture consists of several building blocks that provide functionality for different aspects of cellular network mobility. One building block is network-based macro mobility in IP/MPLS networks. The macro mobility techniques described herein are built on extensions to a routing protocol such as BGP. Another building block relates to transferring subscriber context between network devices while preserving the IP address of the subscriber. The techniques described herein provide a subscriber context transfer mechanism for mobile subscriber management that is built on extensions to a routing protocol such as BGP. Another building block of the mobility architecture is network-based micro mobility based on VPLS.

Claims

1. A method comprising:

receiving, with a gateway device of a cellular network, a request from a mobile device to connect to the gateway device to access a packet-based network, the mobile device in wireless communication with a base station associated with the gateway device;

selecting a mode with the gateway device for routing packets destined for the mobile device, wherein selecting the mode comprises selecting one of an optimal routing mode and a triangular routing mode, wherein the optimal routing mode allows unicast traffic destined for the mobile device to bypass a current anchor device for the mobile device and be routed directly to the gateway device, and wherein the triangular routing mode allows unicast traffic for the mobile device to be routed to the anchor device that tunnels the traffic to the gateway device; and

in accordance with the selected mode, the gateway device advertising a mobile subscriber (MS) virtual private network (VPN) route advertisement to one or more other network devices in the cellular network using an extended routing protocol, wherein the MS VPN route advertisement encodes reachability information associated with the mobile device connected to the gateway device.

2. The method of claim 1,

wherein advertising a MS VPN route advertisement comprises, upon selecting the optimal routing mode with the gateway device, advertising the MS VPN route advertisement with the gateway device to other network devices in the cellular network that are members of a mobile VPN associated with the gateway device, wherein the MS VPN route advertisement encodes a full network address associated with the mobile device.

3. The method of claim 2, wherein the MS VPN route advertisement encodes a next hop of the mobile device, a route distinguisher of the mobile VPN in which the mobile device operates, and a multiprotocol label switching (MPLS) mobile VPN label for reaching the gateway to which the mobile subscriber is connected.

4. The method of claim 2, further comprising:

upon advertising the MS VPN route advertisement, the gateway device operating as an anchor device for the mobile device in place of the current anchor device for the mobile device, wherein operating as an anchor device comprises;

storing subscriber context for the mobile device, and processing data communications associated with the mobile device in accordance with the subscriber context.

5. The method of claim 4, wherein storing the subscriber context comprises storing one or more of a level or quality of service associated with the mobile subscriber, QoS scheduling, rate-limiting, policing parameters, per-flow classifiers/filters, encryption keys, address information, multicast group memberships of the mobile subscriber, and charging and accounting information to account for the services provided to the mobile subscriber.

6. The method of claim 1,

wherein advertising a MS VPN route advertisement comprises, upon selecting the triangular routing mode with the gateway device, advertising a targeted MS VPN route advertisement with the gateway device to the anchor device in the cellular network to enable the anchor device to route packets destined for the mobile device to the gateway device, wherein the targeted MS VPN route advertisement includes a route-target that is an Internet Protocol (IP)-based route-target constructed from an IP address of the anchor device,

the method further comprising receiving, with the gateway device, tunneled packets from the anchor device destined for the mobile device.

7. The method of claim 6, wherein receiving tunneled packets comprises receiving MPLS packets through an MPLS tunnel.

8. The method of claim 1, wherein advertising a MS VPN route advertisement comprises, upon selecting optimal routing mode with the gateway, advertising with the gateway a MS VPN route advertisement that carries a NO_EXPORT community that prevents the MS VPN route advertisement from being advertised outside the autonomous system.

9. The method of claim 1, wherein selecting a mode comprises selecting the mode based on a Service Level Agreement (SLA) associated with the mobile device.

10. The method of claim 1, wherein advertising the MS VPN route advertisement comprises aggregating reachability to a plurality of mobile devices in a single MS VPN route.

11. The method of claim 1, further comprising an autonomous system border router (ASBR) advertising an aggregate MS VPN route advertisement that summarizes reachability to all mobile devices on subnets owned by a plurality of gateway devices in an autonomous system.

12. The method of claim 1, wherein the gateway device is positioned in a first autonomous system (AS), further comprising:

receiving, with the gateway device, a request from a second mobile device to connect to the gateway device to access a packet-based network;

determining, with the gateway device, whether a subnet of the second mobile device is in a second AS different than the first AS; and

advertising an MS VPN route advertisement for the second mobile device only when the subnet of the second mobile device not in a second AS different than the first AS.

13. The method of claim 1, further comprising:

receiving, with the gateway device, a multicast join request from the mobile device, wherein the multicast join request specifies a multicast group for receiving a multicast traffic from a source;

propagating the multicast join request from the gateway device towards a provider edge router selected as an upstream multicast hop (UMH) in accordance with BGP multicast VPN (MPVN);

receiving multicast traffic at the gateway device from the UMH; and

sending the received multicast traffic to the mobile device.

14. The method of claim 1, wherein the gateway device comprises a first gateway device, and wherein the mobile device moves from the first gateway device to a second gateway device, further comprising:

receiving, with the first gateway device, network traffic destined to the mobile device;

tunneling the network traffic to the second gateway device when the first gateway device has received a MS VPN route advertisement from the second gateway device.

15. The method of claim 1, wherein the gateway device comprises a first gateway device, defining a handoff IP gateway zone (HIZ) comprising a set of gateway devices in a geographical vicinity of the first gateway device to which the mobile device is likely to move further comprising:

receiving network traffic destined for the mobile device after the mobile device moves from the first gateway device to a second gateway device; and

tunneling the network traffic to all other gateway devices in the HIZ.

16. The method of claim 1, wherein the extended routing protocol comprises an extended Border Gateway Protocol (BGP).

17. The method of claim 16, further comprising:

processing, with the gateway device, data communications associated with a data session with the mobile device in accordance with a subscriber context associated with the mobile device, wherein the subscriber context specifies subscriber-specific information defining one or more policies that are applied to the data communications,

wherein the MS VPN route advertisement encodes the subscriber context as BGP attributes of the MS VPN route advertisement.

18. The method of claim 17, wherein advertising the MS VPN route advertisement comprises advertising a MS VPN route advertisement that encodes the subscriber context as network layer reachability information (NLRI) that is communicated in accordance with the extended BGP protocol.

19. The method of claim 17, wherein the extended BGP protocol defines the subscriber context as opaque BGP data such that network devices that do not support the extension ignore the encoded subscriber context.

20. A gateway device of a cellular network comprising:

an interface configured to receive a request from a mobile device to connect to the gateway device to access a packet-based network, the mobile device in wireless communication with a base station associated with the gateway device; and

a control unit configured to select a mode for routing packets destined for the mobile device by selecting one of an optimal routing mode and a triangular routing mode, wherein the optimal routing mode allows unicast traffic destined for the mobile device to bypass a current anchor device for the mobile device and be routed directly to the gateway device, and wherein the triangular routing mode allows unicast traffic for the mobile device to be routed to the anchor device that tunnels the traffic to the gateway device,

wherein the control unit is configured to execute a routing protocol that has been extended to advertise a mobile subscriber (MS) virtual private network (VPN) route advertisement to one or more other network devices in the cellular network, wherein the MS VPN route advertisement encodes reachability information associated with the mobile device connected to the gateway device.

21. The gateway device of claim 20, wherein the extended routing protocol comprises an extended Border Gateway Protocol (BGP).

22. The gateway device of claim 21, wherein the control unit is configured to process data communications associated with a data session with the mobile device in accordance with a subscriber context associated with the mobile device, wherein the subscriber context specifies subscriber-specific information defining one or more policies that are applied to the data communications,

wherein the MS VPN route advertisement encodes the subscriber context as network layer reachability information (NLRI) of the MS VPN route advertisement that is communicated in accordance with the extended BGP protocol.

23. The gateway device of claim 20, wherein upon selecting the optimal routing mode with the gateway device, the control unit is configured to advertise the MS VPN route advertisement to other network devices in the cellular network that are members of a mobile VPN associated with the gateway device, wherein the MS VPN route advertisement encodes one or more of a full network address associated with the mobile device, a next hop of the mobile device wherein the next hop comprises the gateway device, a route distinguisher, and a multiprotocol label switching (MPLS) mobile VPN label for reaching the gateway to which the mobile subscriber is connected.

24. The gateway device of claim 20, wherein upon selecting the triangular routing mode with the gateway device, the control unit is configured to advertise a targeted MS VPN route advertisement with the gateway device to the anchor device in the cellular network to enable the anchor device to route packets destined for the mobile device to the gateway device, wherein the targeted MS VPN route advertisement includes a route-target that is an Internet Protocol (IP)-based route-target constructed from an IP address of the anchor device, and wherein the interface is configured to receive tunneled packets from the anchor device destined for the mobile device

25. The gateway device of claim 20, wherein the control unit is configured to select the mode based on a Service Level Agreement (SLA) associated with the mobile device.

26. The gateway device of claim 20, wherein the control unit is configured to execute a BGP multicast VPN (MPVN) protocol, and wherein upon the gateway device receiving a multicast join request from the mobile device, the control unit is configured to propagate the multicast join request from the gateway device towards a provider edge router selected as an upstream multicast hop (UMH) in accordance with the BGP MVPN protocol.

27. A system comprising:

a first gateway device associated with a first base station;

a second gateway device associated with a second base station;

a mobile device in wireless communication with the first base station after being in wireless communication with the second base station; and

an anchor device that acts as a main repository for a subscriber context associated with the mobile device,

wherein the first gateway device comprises;

an interface configured to receive a request from the mobile device to connect to the first gateway device to access a packet-based network; and

a control unit configured to select one of an optimal routing mode and a triangular routing mode for routing packets destined for the mobile device, wherein the optimal routing mode allows unicast traffic destined for the mobile device to bypass a current anchor device for the mobile device and be routed directly to the gateway device, and wherein the triangular routing mode allows unicast traffic for the mobile device to be routed to the anchor device that tunnels the traffic to the gateway device,

wherein the control unit is configured to execute a routing protocol that has been extended to advertise a mobile subscriber (MS) virtual private network (VPN) route advertisement to one or more other network devices in a cellular network of the system, wherein the MS VPN route advertisement encodes reachability information associated with the mobile device connected to the gateway device,

28. A computer-readable storage medium comprising instructions for causing a programmable processor of a gateway device of a cellular network to:

receive a request from a mobile device to connect to the gateway device to access a packet-based network, the mobile device in wireless communication with a base station associated with the gateway device;

select one of an optimal routing mode and a triangular routing mode for routing packets destined for the mobile device, wherein the optimal routing mode allows unicast traffic destined for the mobile device to bypass a current anchor device for the mobile device and be routed directly to the gateway device, and wherein the triangular routing mode allows unicast traffic for the mobile device to be routed to the anchor device that tunnels the traffic to the gateway device; and

in accordance with the selected mode, advertise a mobile subscriber (MS) virtual private network (VPN) route advertisement to one or more other network devices in the cellular network using an extended routing protocol, wherein the MS VPN route advertisement encodes reachability information associated with the mobile device connected to the gateway device.

29. A method for routing packets within a network comprising:

establishing a data communication session between a cellular mobile device and a packet-based network via a first cellular base station and first gateway associated with the first cellular base station, wherein establishing the data communication session comprises binding the cellular mobile device to an anchor device associated with the first gateway and storing subscriber context for the cellular mobile device with the anchor device;

after establishing the data communication session, receiving, with a second gateway device of a cellular network, a request from the cellular mobile device to connect to the second gateway device to access the packet-based network;

selecting a mode with the second gateway device for routing packets of the data communication session from the packet-based network to the mobile device, wherein selecting the mode comprises selecting between;

(1) a first routing mode that allows the packets of the data communication session destined for the mobile device to bypass the anchor device and be routed directly to the second gateway device, and (2) a second routing mode that allows the packets of the data communication session to be routed to the anchor device that forwards the traffic to the second gateway device;

upon selecting the first routing mode with the second gateway device, advertising a mobile subscriber (MS) virtual private network (VPN) route advertisement with the second gateway device to other network devices in the cellular network that are members of a mobile VPN associated with the second gateway device, wherein the MS VPN route advertisement encodes a full network address associated with the mobile device and a multiprotocol label switching (MPLS) mobile label for reaching the second gateway to which the mobile subscriber is connected; and

upon selecting the triangular routing mode with the gateway device, advertising a targeted MS VPN route advertisement with the second gateway device to the anchor device in the cellular network to enable the anchor device to remain the anchor device and route packets destined for the mobile device to the second gateway device.