IP ROUTING OPTIMIZATION IN AN ACCESS NETWORK

• US 20080151837A1
• Filed: 03/11/2008
• Published: 06/26/2008
• Est. Priority Date: 03/09/1999
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: RAJAMIEMI, Jaakko, SOININEN, Jonne, MUHONEN, Ahti
• Granted Patent: US 8,255,540 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• CPC Class Codes: H04W 8/065 involving selection of the user mobility server
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

In an access network which supports a mobile IP protocol, a mobile station may perform several handovers between access nodes during a long session which may cause inefficient mobile IP routing. In the present invention, an access node, which is the target of a handover during an IP session, is arranged to check the preferred mobility agent in respect of the optimal routing on the mobile IP level, and if a more preferred mobility agent is available and not the same as a current mobility agent, the connection to the current mobility agent is closed, and a new connection to the preferred mobility agent of the respective access node is opened. In merit of the new connection established by the access node to the preferred mobility agent, the agent advertisement messages sent by the new mobility agent can be received by the mobile node, and thereby the mobile node is able to detect the change of the attachment point (i.e. mobility agent) and to initiate standard mobile IP registration.

Claims

1. A method of providing macro mobility management for a mobile node in radio access system comprising a plurality of mobile nodes, a first and a second access node serving said mobile nodes within a first and second parts of the access system, respectively, at least one first gateway node for interfacing said first part of the access system with external networks, and a first mobility entity which is associated with said at least one first gateway node and arranged to provide macro mobility management routing services to the mobile nodes while registered to the first part of the access system, said method comprising:

establishing a session between one of said plurality of mobile nodes and a second party via said first access node and said first mobility entity;

rerouting the session via said second access node in response to a movement of said one of mobile nodes to said second part of the access system;

storing, in said second access node, an identity of a preferred mobility entity of said second access node;

checking, in said second access node, in response to a movement of said one mobile node from said first access node to said second access node, whether the identity of said first mobility entity and said stored identity of said preferred mobility entity match or not; and

reacting to said checking by

A) maintaining a connection from said second access node to said first mobility entity if the identities match, and

B) closing a connection from said second access node to said first mobility entity and opening a new connection to said preferred mobility entity if said identities do not match, and initiating macro mobility management registration.

2. The method according to claim 1, wherein said closing and opening of the connection comprise closing and opening of one or more packet protocol contexts.

3. The method according to claim 2, comprising transferring the packet protocol contexts of a mobile station which the mobile node is associated with from the first access node to the second access node, along with information which indicates which one or ones of the packet radio protocol contexts relate to the macro mobility management;

distinguishing the macro mobility management related packet protocol contexts from other packet protocol contexts on the basis of said information at the second access node; and

performing said opening and closing solely on the macro mobility management related packet protocol contexts.

4. The method according to claim 1, wherein said preferred mobility entity of said second access node is a foreign agent associated with a gateway node in said second part of the access system.

5. The method according to claim 1, wherein said identity comprises an address of the mobility entity.

6. An access system, comprising

a plurality of mobile nodes;

a first and a second access node serving said mobile nodes within a first and second parts of the access system, respectively;

at least one first gateway node for interfacing said first part of the access system with external networks;

a first mobile entity which is associated with said at least one first gateway node and arranged to route a connection to any one of said mobile nodes while said mobile node is registered to the first part of the access system;

a rerouting mechanism by which said connection initially routed via said first access node and said first mobility entity can be rerouted via said second access node in response to a movement of said one of mobile nodes to said second part of the access system;

a mechanism which checks whether there is a second mobility entity which is more preferred in respect of routing than said first mobile entity; and

a mechanism which opens a new connection from said second access node to said second mobility entity if said more preferred second mobility entity is available according to said checking,

said mobile node comprising a mechanism which detects a change of attachment by means of said new connection and to initiate macro mobility management registration.

7. The system according to claim 6, comprising a mechanism which closes a connection to said first mobility entity when said more preferred second mobility entity is available according to said checking.

8. The system according to claim 6, comprising said macro mobility management being Internet Protocol-type, or IP-type, mobility management,

said second mobility entity being arranged to send an entity advertisement message to said one mobile node over said new connection,

said mobile node being arranged to detect a change of attachment by means of said entity advertising message and to initiate mobile IP registration.

9. The system according to claim 6, wherein said preferred mobility entity of said second access node comprises a foreign agent associated with a gateway node in said second part of the access system.

10. The system according to claim 6, wherein said second access node is arranged to conduct said checking.

11. The system according to claim 10, wherein the second access node is arranged to store the identity comprising an address of the preferred foreign agent for the checking purposes.

12. The system according to claim 6, wherein said closing and opening of the connection comprise closing a packet protocol context in the gateway node of the first mobility entity and opening a packet protocol context in the gateway node of the preferred mobility entity.

13. The system according to claim 12, wherein said maintaining of the connection comprises updating of a packet protocol context of the mobile node in the gateway node of the first mobility entity.

14. The system according to claim 12, wherein packet protocol contexts of a mobile station which the mobile node is associated with are associated with information which indicates which one or ones of the packet protocol contexts relate to the macro mobility management, and wherein the access node is arranged to distinguish the macro mobility management related packet protocol contexts from possible other packet protocol contexts on the basis of said information and to said opening and closing solely on the macro mobility management related packet protocol contexts.

15. The system according to claim 14, wherein said information is provided in a message transferring the packet protocol contexts from said other access node to said access node.

16. An access node for an access system comprising a plurality of mobile nodes, access nodes serving said mobile nodes within respective parts of the access system, at least two gateway nodes for interfacing the access system with external networks, and at least two mobility entities which are associated with different ones of said at least two gateway nodes and arranged to provide macro mobility management routing services to the mobile nodes while registered to the access system, said access node comprising:

means for storing the identity comprising an address of said preferred other mobility entity of said access node;

means for checking, in response to a movement of said mobile node from another access node to said access node whether the identity of a first mobility entity used by said other access node and said stored identity of said preferred mobility entity match or not; and

a mechanism which opens a new connection to said preferred other mobile entity, if said preferred other mobile entity is available.

17. The access node of claim 16, wherein said means for storing the identity comprises a memory which stores an identity comprising an address, of a preferred mobile entity of said access node, and

wherein said means for checking comprises a mechanism which checks, in response to a movement of said mobile node from another access node to said access node whether the identity of a first mobility entity used by said other access node and said stored identity of said preferred mobility entity match or not,

said access node further comprising:

means for maintaining a connection to said first mobility entity if the identities match; and

means for closing the connection to said first mobility entity and opening new connection to said preferred mobility entity if said identities do not match.

18. An access node for a radio access system comprising a plurality of mobile nodes, access nodes serving said mobile nodes within respective parts of the access system, at least two gateway nodes for interfacing the access system with external networks, and at least two mobility entities which are associated with different ones of said at least two gateway nodes and arranged to provide macro mobility management routing services to the mobile nodes while registered to the access system, said access node comprising:

means for checking, when a mobile node having a connection through another access node and a first mobility entity is accessing the system via said access node, whether there is another mobility entity which is more preferred in respect of routing than said first mobility entity;

means responsive to said checking means for opening a new connection to said preferred other mobility entity if said more preferred other mobility entity is available; and

means for closing a connection to said first mobility entity when said more preferred other mobility entity is available;

wherein said means for closing and opening of the connection comprise means for closing a packet protocol context in the gateway node of the first mobility entity and opening a packet protocol context in the gateway node of the preferred mobility entity.

19. The access node according to claim 18, wherein said means for maintaining the connection comprise means for updating a packet protocol context of the mobile node in the gateway node of the first mobility entity.

20. The access node according to claim 18, wherein packet protocol contexts of a mobile station which the mobile node is associated with are associated with information which indicates which one or ones of the packet protocol contexts relate to the macro mobility management, and wherein the access node is arranged to distinguish the macro mobility management related packet protocol contexts from possible other packet protocol contexts based on said information and to perform said steps of opening and closing solely on the macro mobility management related packet protocol contexts.

21. The access node according to claim 20, wherein said information is provided in a message transferring the packet protocol contexts from said other access node to said access node.

22. The access node according to claim 18, wherein said macro mobility management comprises Internet Protocol (IP) type mobility management.

23. An access node for an access system comprising a plurality of mobile nodes, access nodes serving said mobile nodes within respective parts of the access system, at least two gateway nodes for interfacing the access system with external networks, and at least two mobility entities which are associated with different ones of said at least two gateway nodes and arranged to provide macro mobility management routing services to the mobile nodes while registered to the access system, said access node comprising:

a memory which stores an identity, such as an address, of a preferred mobility entity of said access node;

a mechanism which checks, in response to a movement of said mobile node from another access node to said access node whether the identity of said first mobility entity used by said other access node and said stored identity of said preferred mobility entity match or not;

a mechanism which maintains a connection to said first mobility entity if the identities match, by maintaining a packet protocol context in the gateway node associated with the first mobility entity; and

a mechanism which closes the connection to said first mobility entity by closing a packet protocol context in the gateway node associated with the first mobility entity, and opens a new connection to said preferred mobility entity by opening a packet protocol context in a gateway node associated with the preferred mobility entity, if said identities do not match.

24. An access node for an access system comprising a plurality of mobile nodes, access nodes serving said mobile nodes within respective parts of the access system, at least two gateway nodes for interfacing the access system with external networks, and at least two mobility entities which are associated with different ones of said at least two gateway nodes and arranged to provide macro mobility management routing services to the mobile nodes while registered to the access system, said access node comprising:

a memory which stores information on a preferred one of said mobility entities for said access node;

a first mechanism which checks, in response to a movement of said mobile node from another access node to said access node whether a first mobility entity used by another access node corresponds to said preferred mobility entity according to said stored information;

a second mechanism which maintains a connection to said first mobility entity if said first mobility entity corresponds to said preferred mobility entity according to said stored information, by maintaining a packet protocol context providing a connection from the access node to the first mobility entity; and

a third mechanism which closes the connection to said first mobility entity by closing a packet protocol context providing a connection to the first mobility entity, and opens a new packet protocol context providing a new connection to said preferred mobility entity, if said first mobility entity does not correspond to said preferred mobility entity according to said stored information.

25. An access node according to claim 24, wherein the packet protocol context of the mobile node is associated with information which indicates which one or ones of the packet protocol contexts relate to the macro mobility management, and wherein the access node comprises a fourth mechanism which distinguishes a macro-mobility-management-related packet protocol context from possible other packet protocol contexts on the basis of said information, said first, second and third mechanisms being enabled only for the macro-mobility-management-related packet protocol context.

26. An access node for an access system comprising a plurality of mobile nodes, access nodes serving said mobile nodes within respective parts of the access system, at least two gateway nodes for interfacing the access system with external networks, and at least two foreign agents which are associated with different ones of said at least two gateway nodes and arranged to provide macro mobility management routing services to the mobile nodes while registered to the access system, said access node comprising:

a memory which stores information on preferred one of said foreign agents for said access node;

a first mechanism which checks, in response to a movement of said mobile node from another access node to said access node whether a first foreign agent used by said other access node corresponds to said preferred mobility entity according to said stored information;

a second mechanism which maintains a connection to said first mobility entity if said first foreign agent corresponds to said preferred foreign agent according to said stored information, by maintaining a packet protocol context providing a connection from the access node to the first foreign agent; and

a third mechanism which closes the connection to said first foreign agent by closing a packet protocol context providing a connection to the first foreign agent, and opens a new packet protocol context providing a new connection to said preferred foreign agent, if said first foreign agent does not correspond to said preferred foreign agent according to said stored information.

27. A packet radio support node for a packet radio access system comprising a plurality of mobile nodes, packet radio support nodes serving said mobile nodes within respective parts of the access system, at least two gateway nodes for interfacing the packet radio access system with external networks, and at least two foreign agents which are associated with different ones of said at least two gateway nodes and arranged to provide macro mobility management routing services to the mobile nodes while registered to the packet radio access system, said packet radio support node comprising:

a memory which stores information on preferred one of said foreign agents for said packet radio support node;

a first mechanism which checks, in response to a movement of said mobile node from another packet radio support node to said packet radio support node whether a first foreign agent used by said other packet radio support node corresponds to said preferred foreign agent according to said stored information;

a second mechanism which maintains a connection to said first foreign agent if said first foreign agent corresponds to said preferred foreign agent according to said stored information, by maintaining a packet protocol context providing a connection from the packet radio support node to the first foreign agent; and

a third mechanism which closes the connection to said first foreign agent by closing a packet protocol context providing a connection to the first foreign agent, and opens a new packet protocol context providing a new connection to said preferred foreign agent, if said first foreign agent does not correspond to said preferred foreign agent according to said stored information.