METHOD AND APPARATUS FOR USE IN A COMMUNICATIONS NETWORK

• US 20100226283A1
• Filed: 10/26/2007
• Published: 09/09/2010
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Larsson, Conny, Rune, Johan
• Granted Patent: US 8,774,049 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• CPC Class Codes: H04W 60/005 Multiple registrations, e.g. multihoming
• CPC Class Codes: H04W 8/06 Registration at serving network Location Register, VLR or user mobility server
• CPC Class Codes: H04W 8/087 for preserving data network PoA address despite hand-offs
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/182 Network node acting on behalf of an other network entity, e.g. proxy

Abstract

A method and apparatus for use in a communications network in which a Mobile Node accesses the communications network via a proxy node. The proxy node is arranged to handle mobility signalling on behalf of the Mobile Node. At a mobility anchor function, such as a Local Mobility Anchor, a first Care-of-Address associated with the Mobile Node is registered. When the mobility anchor function receives a registration request to register a second Care-of-Address associated with the Mobile Node, it sends a request message to the proxy node acting on behalf of the Mobile Node. The request message instructs the proxy node to check whether the Mobile Node is reachable using the first Care-of-Address.

Claims

1. A method for use in a communications network in which a Mobile Node accesses the communications network via a proxy node, the proxy node arranged to handle mobility signalling on behalf of the Mobile Node, the method comprising:

at a mobility anchor function, registering a first Care-of-Address associated with the Mobile Node

receiving a registration request to register a second Care-of-Address associated with the Mobile Node; and

sending a request message to the proxy node acting on behalf of the Mobile Node, the request message instructing the proxy node to check whether the Mobile Node is reachable using the first Care-of-Address.

2. The method according to claim 1, wherein the communications network is selected from one of a Proxy Mobile IPv4 network and a Proxy Mobile IPv6 network, the mobility anchor function is a Local Mobility Anchor function, and the proxy node is a Mobile Access Gateway.

3. The method according to claim 1 or 2, further comprising

receiving a response message from the proxy node, the response message being triggered by the request message.

4. The method according to claim 3, wherein the response message requests the mobility anchor function to deregister the first Care-of-Address.

5. The method according to claim 3, wherein the response message includes information informing the mobility anchor function that the Mobile Node can not be reached using the first Care-of-Address.

6. The method according to claim 3, wherein the response message includes information informing the mobility anchor function that the Mobile Node can be reached using the first Care-of-Address.

7. The method according to any one of the preceding claims, comprising:

sending the request message to a plurality of proxy nodes, each proxy node associated with a Care-of-Address, each Care-of-Address associated with the Mobile Node;

8. The method according to any one of the preceding claims, wherein the request message is selected from a Proxy Mobile IPv6 message and a Proxy Mobile IPv4 Register Revocation message, the Proxy Mobile IPv4 Register Revocation message comprising a flag indicating that revocation of the Care-of-Address is conditional upon the Mobile Node being unreachable.

9. The method according to any one of the preceding claims, further comprising, at the proxy node, after receiving the request message from the mobility anchor function, determining the reachability status of the Mobile Node.

10. The method according to claim 9, wherein the determining the reachability status of the Mobile Node comprises sending a query message to the Mobile Node.

11. The method according to claim 10, wherein the query message is selected from one of an Internet Control Message Protocol for IPv4 Echo Request message, an Internet Control Message Protocol for IPv6 Echo Request message, a Neighbour Solicitation message and an Address resolution Protocol message.

12. The method according to any one of the preceding claims, further comprising:

after receiving the registration request to register a second Care-of-Address associated with the Mobile Node, at the mobility anchor function, caching copies of all incoming packets directed to the first Care-of-Address; and

in the event that the Mobile Node is unreachable using the first Care-of-Address, sending the cached packets to the second Care-of-Address, clearing the cache and stopping caching copies of all incoming packets directed to the first Care-of-Address.

13. The method according to any one of claims 1 to 11, further comprising:

after receiving the registration request to register a second Care-of-Address associated with the Mobile Node, at the mobility anchor function, caching copies of all incoming packets directed to the first Care-of-Address;

at the mobility anchor function, receiving a message from the proxy node indicating that the Mobile Node is reachable using the first Care-of-Address; and

clearing the cache and stopping caching copies of incoming packets directed to the first Care-of-Address.

14. A mobility anchor node for use in a communications network in which a Mobile Node accesses the communications network via a proxy node, the mobility anchor node comprising:

means for registering a first Care-of-Address associated with a Mobile Node

a receiver for receiving a registration request to register a second Care-of-Address associated with the Mobile Node; and

a transmitter for transmitting a request message to the proxy node, the request message instructing the proxy node to determine whether the Mobile Node is reachable using the first Care-of-Address.

15. The mobility anchor node according to claim 14, further comprising:

means for receiving a response message from the proxy node, the response message being triggered by the request message; and

means for de-registering the first Care-of-Address at the mobility anchor function.

16. The mobility anchor node according to claim 14 or 15, wherein the transmitter is arranged to transmit the request message to a plurality of proxy nodes, each proxy node associated with a Care-of-Address, each Care-of-Address associated with the Mobile Node.

17. The mobility anchor node according to claim 14, 15 or 16, further comprising:

means for caching copies of all incoming packets directed to the first Care-of-Address; and

means for, in the event that the Mobile Node is unreachable using the first Care-of-Address, sending the cached packets to the second Care-of-Address and clearing the cache.

18. A proxy node for use in a communications network in which a Mobile Node accesses the communications network via a proxy node, the node comprising:

a receiver for receiving a request message sent from a mobility anchor node, the request message related to the reachability of a Mobile Node attached to the proxy node using a Care-of-Address;

a transmitter for sending a query to the Mobile Node; and

means for determining whether the Mobile Node is reachable using the Care-of-Address; and

means for sending a message to the mobility anchor node, the message comprising information selected from information informing the mobility anchor node that the Mobile Node is unreachable using the first Care-of-Address, information informing the mobility anchor node that the Mobile Node is reachable using the first Care-of-Address, and information requesting the mobility anchor function to deregister the first Care-of-Address.