Methods and apparatus for separating home agent functionality

• US 20050174984A1
• Filed: 05/04/2004
• Published: 08/11/2005
• Est. Priority Date: 02/06/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: O'Neill, Alan
• Granted Patent: US 7,697,501 B2
• Time in Patent Office: Days
• US Class Current: 370/349
• CPC Class Codes: H04L 45/58 Association of routers
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 8/12 between location registers or mobility servers
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

MIP Home Agent (HA) architectures are described that decompose, e.g., split, packet forwarding control functionality from actual data packet forwarding operations performed by a conventional MIP HA. This places MIP routing control in a node which is distinct from the tunnel end-points which perform packet forwarding operations to direct packets including a mobile'"'"'s Home Address. Tunneling establishment and control functionality is implemented by what is referred to herein as decomposed HA (DHA) while data packet forwarding and redirection is performed, under the control of the DHA, by a tunneling agent (TA) node. The tunneling agent node serves as the data packet redirection node for a mobile as it moves from one location to another and may be located outside of a firewall used to protect the DHA. Tunnel endpoint nodes (Mobile Nodes and/or Access Nodes) send tunnel packets to the tunnel agent whilst directing control signaling packets to the DHA.

Claims

1. A method of supporting mobility in a communications system, the system including a mobile node, a routing control node, a data packet forwarding node and an access node, said access node serving as the mobile nodes point of attachment to the network via a wireless link, the method comprising:

operating the mobile node to transmit a forwarding control message to the routing control node via said access node, said message being forwarded to said routing control node over a control path which does not traverse said data packet forwarding node;

operating the routing control node to establish a data packet forwarding path between the data packet forwarding node and one of said access node and mobile node, said routing control node being outside said data packet forwarding path; and

operating the routing control node to transmit a response message to said mobile node indicating acceptance of the request for establishment of said data packet forwarding path.

2. The method of claim 1, wherein said mobile node has a home address associated with said data packet forwarding node, packets intended for said mobile node including said home address being routed to said data packet forwarding node, the method further comprising:

operating the data packet forwarding node to redirect packets including said home address of said mobile node along said established data packet forwarding path.

3. The method of claim 1, further comprising:

operating the data packet forwarding node to transmit a signal to the routing control node indicating installation of a tunnel state entry for the packet forwarding path.

4. The method of claim 1, further comprising:

operating the data packet forwarding node to transmit a routing advertisement for an address associated with a first identifier;

operating said access node to transmit a routing advertisement for an address associated with a second identifier; and

wherein said forwarding control message to the routing control node includes a request for installation in a table in said routing control node of a tunnel state entry associating the first and second identifiers.

5. The method of claim 4,

wherein said forwarding control message and said response message are IP signals used for mobility signaling;

wherein the first identifier is a home address (HoA) of the mobile node;

wherein the third node is a Home Agent which performs packet routing control functions used to support mobile node mobility;

wherein the second identifier is one of a Colocated Care of Address of said mobile node and a Care of Address of a mobility Agent located at said access node; and

wherein the data packet forwarding node is a Tunnel Agent.

6. The method of claim 4,

wherein the first identifier is one of the following identifiers associated with a mobile node:

a fully qualified domain name (FDQN), a Network Access Identity (NAI), a SIP Universal Resource Identifier (URI), an identifier derived from an International Mobile Subscriber Identity (IMSI), a globally unique end node identifier; and

wherein the second identifier is one of the following identifiers associated with an access node;

a FQDN, an NAI, and a private access node identifier assigned by the operator.

7. The method of claim 4, wherein said system further includes another data packet forwarding node and a third identifier being associated with said another data packet forwarding node, the method further comprising:

operating said another data packet forwarding node to transmit an additional routing advertisement for the address associated with the first identifier;

operating the data packet forwarding node to receive a signal further indicating the third identifier; and

operating said data packet forwarding node to store said third identifier and associate it with a tunnel state entry for the first and second identifiers.

8. The method of claim 4, further including:

operating the data packet forwarding node to redirect packets comprising;

operating the data packet forwarding node to receive a redirected packet from the one of the mobile node and access node acting as a tunnel endpoint node, said redirected packet including a source address that includes said address associated with the second identifier;

operating the data packet forwarding node to compare an additional source address included in the received redirected packet to tunnel state entries stored at the data packet forwarding node, wherein said additional source address includes said address associated with the first identifier; and

operating the data packet forwarding node to verify that the tunnel state entry that includes said address associated with first identifier maps said address associated with the first identifier to said address associated with the second identifier.

9. The method of claim 4, further comprising:

operating the routing control node to transmit a first signal to the data packet forwarding node, said first signal requesting the installation of a tunnel state entry in the packet forwarding node, said first signal including the first and second identifiers;

operating the data packet forwarding node to receive the first signal from the routing control node;

operating the data packet forwarding node to install said address associated with the first identifier and said address associated with the second identifier in a tunnel state entry in the data packet forwarding node;

operating the data packet forwarding node to transmit a second signal toward the routing control node, said second signal indicating installation of the tunnel state entry in the data packet forwarding node associated with the first identifier; and

wherein said step of transmitting the second signal toward the routing control node follows the successful installation of the tunnel state entry in the data packet forwarding node.

10. The method of claim 4, wherein the data packet forwarding node includes a security routine and a security association that is also known to the routing control node, the method further comprising:

operating the data packet forwarding node to determine a security parameter to be included in a first signal to be transmitted to the routing control node, using the second identifier included in said transmitted signal; and

wherein said security parameter is used by the routing control node to perform one of a decryption operation, an authentication operation and an integrity checking operation using the second identifier included in said first signal transmitted from the data packet forwarding node to the routing control node.

11. The method of claim 5, further comprising:

operating the mobile node to notify the routing control node when it changes the access node to which it is attached to a new access node.

12. The method of claim 11, further comprising:

operating the routing control node to direct a packet including said Home Address of said mobile node to said new access node, at least some of said directed packets including data corresponding to a communications session between said mobile node and another mobile node, said data being one of voice and text data.

13. A communications system comprising:

a mobile node having a Home Address;

a routing control node for receiving routing control messages from a mobile node and for controlling the redirection of packets including the Home Address of said mobile node towards the mobile node'"'"'s current location;

a data packet forwarding node for receiving packets including said Home Address and for redirecting said packets towards the current location of said mobile node;

an access node, said access node serving as the mobile nodes point of attachment to a network which includes said access node and said routing control node, said access node being coupled to said mobile node via a wireless link;

said mobile node including means for transmitting a forwarding control message to the routing control node via said access node, said message being forwarded to said routing control node over a control path extending between said access node and said routing control node which does not traverse said data packet forwarding node; and

said routing control node including;

i) means for establishing a data packet forwarding path between the data packet forwarding node and one of said access node and mobile node, said routing control node being outside said data packet forwarding path; and

ii) means for transmitting a response message to said mobile node indicating acceptance of the request for establishment of said data packet forwarding path.

14. The method of claim 13,

wherein said mobile node has a home address associated with said data packet forwarding node, packets intended for said mobile node including said Home Address being routed to said data packet forwarding node;

and

wherein said data packet forwarding node includes means for redirecting packets including said home address of said mobile node along said established data packet forwarding path.

15. The method of claim 13, wherein said data packet forwarding node further includes:

a set of tunnel state information;

means for updating an entry in said tunnel state information corresponding to said mobile node'"'"'s Home Address in response to a control signal received from said routing control node; and

means for sending a signal to the routing control node indicating installation of a tunnel state entry for the packet forwarding path used to redirect data packets including said mobile nodes Home Address.

16. The method of claim 13,

wherein said data packet forwarding node includes means for transmitting a routing advertisement for an address associated with a first identifier;

wherein said access node includes means for transmitting a routing advertisement for an address associated with a second identifier; and

wherein said forwarding control message to the routing control node includes a request for installation in said set of tunnel state information of a state entry associating the first and second identifiers.

17. A communications method for use with a communication system including a first node, an access node, a second node, and a third node, wherein one of said access node and the first node operates as a tunnel endpoint node, the method comprising:

operating said second node to transmit a routing advertisement for an address associated with a first identifier;

operating said access node to transmit a routing advertisement for an address associated with a second identifier;

operating the tunnel endpoint node to transmit a first signal towards the third node, said signal requesting installation, in a table in said third node, of a tunnel state entry associating the first and second identifiers;

operating the tunnel endpoint node to receive a second signal originating from the third node indicating that the third node has installed said tunnel state entry; and

operating said tunnel endpoint node to receive a redirected data packet from the second node, said redirected packet including a data packet with a destination address including the address associated with the first identifier.

18. The method of claim 17,

wherein the first and second signals are IP signals used for mobility signaling;

wherein the first identifier is a home address (HoA) of said first node;

wherein the third node is a decomposed Home Agent;

wherein the second identifier is one of a Colocated Care of Address of said first node and a Care of Address of a mobility Agent located at said access node; and

wherein the second node is a Tunnel Agent.

19. The method of claim 17, wherein said system further includes a fourth node, the method further comprising:

operating said fourth node to transmit a routing advertisement including said address associated with the first identifier; and

operating said tunnel endpoint node to receive a redirected data packet from the fourth node, said redirected packet including a data packet destination address that includes said address that is associated with the first identifier.

20. The method of claim 17, wherein said second signal originated by the third node is received from the second node, the method further comprising:

operating said tunnel endpoint node to store a source address of the redirected packet as an identifier of the second node in a tunnel state entry, included in the tunnel endpoint node, that includes the address associated with the first identifier.

21. The method of claim 17, wherein said second signal received at the tunnel endpoint node further includes an identifier for the second node, the method further comprising:

operating said tunnel endpoint node to determine an address associated with the identifier of the second node; and

operating said tunnel endpoint node to store said determined address associated with the identifier of the second node in a tunnel state entry that includes the address associated with the first identifier.

22. The method of claim 21, wherein said second signal received at the tunnel endpoint node, that includes an identifier for the second node, further includes a security parameter derived from a security association known to both the tunnel endpoint node and the third node, the method further comprising;

operating said tunnel endpoint node to process the security parameter to perform at least one of;

a decryption operation, and an authentication operation and an operation checking the integrity of using the identifier of the second node included in said received signal.

23. The method of claim 21, wherein said second signal received at the tunnel endpoint node further includes an identifier identifying the fourth node.

24. The method of claim 17, wherein the first signal is first addressed to said second node.

25. The method of claim 24, further comprising:

operating said tunnel endpoint node to determine said address of the second node and to add said address to the first signal.

26. The method of claim 24, wherein said address of the second node is indicated in a third signal received at the tunnel endpoint node prior to receipt of any of said second signals.

27. The method of claim 17, further comprising:

operating the tunnel endpoint node to store a data packet including a source address that includes said address associated with the first identifier;

operating the tunnel endpoint node to determine the address of the second node from tunnel state entry information stored in the tunnel endpoint node, the stored tunnel state information including the address associated with the first identifier;

operating the tunnel endpoint node to process the stored data packet to generate and store a redirected packet with a destination address that includes the address of the second node; and

operating the tunnel endpoint node to transmit the redirected packet to the second node.

28. A communications method for use in a communications including a first node, an access node, a second node, and a third node, wherein one of said access node and the first node operates as a tunnel endpoint node, the method comprising:

operating the second node to transmit a routing advertisement for an address associated with a first identifier, said second node including tunnel state entries that map between an addresses associated with the first identifier and address associated with a second identifier;

operating said access node to transmit a routing advertisement for the address associated with the second identifier;

operating the second node to transmit a first signal towards the third node indicating installation of a tunnel state entry associated with the first identifier, said first signal including the second identifier;

operating the second node to receive a data packet including a destination address that includes said address associated with the first identifier;

operating the second node to redirect said received data packet, said redirected packet being modified by said second node to add a destination address that includes said address associated with the second identifier.

29. The communications method of claim 28,

wherein said address that is associated with said first identifier includes the first identifier;

and

wherein said address that is associated with said second identifier includes the second identifier.

30. The communications method of claim 28, further comprising:

operating the second node to receive a redirected packet from the tunnel endpoint node, said redirected packet including a source address that includes said address associated with the second identifier;

operating the second node to compare an additional source address included in the received redirected packet to tunnel state entries stored at the second node, wherein said additional source address includes said address associated with the first identifier; and

operating the second node to verify that the tunnel state entry that includes said address associated with the first identifier maps said address associated with the first identifier to said address associated with said second identifier.

31. The communications method of claim 28, wherein said second node includes a security routine and a security association that is also known to the third node, the method further comprising:

operating the second node to determine a security parameter to be included in said first signal to be transmitted to the third node, using the second identifier included in said transmitted signal;

wherein said security parameter is used by the third node to perform one of a decryption operation, an authentication operation and an integrity checking operation using the second identifier included in the first signal transmitted from the second node to the third node.

32. The method of claim 28, further comprising:

operating the second node to receive a second signal from the third node, said second signal requesting the installation of said tunnel state entry in the second node, said second signal including the first and second identifiers;

operating the second node to install said address associated with the first identifier and said address associated with the second identifier in said tunnel state entry; and

wherein said step of transmitting the first signal towards the third node follows successful installation of the tunnel state entry in the second node.

33. The communications method of claim 32, wherein said second signal received by said second node from the third node includes a security parameter derived from a security association and security routine known to both the second node and the third node, the method further comprising:

operating said second node to process the security parameter to perform one of a decryption operation, an authentication operation and an integrity check operation using the first and second identifiers.

34. The communications method of claim 32, wherein said second signal received by the second node from the third node includes a sequence number value, the method further comprising:

operating said second node to validate the received sequence number value; and

operating the second node to include said validated received sequence number value in the first signal transmitted to the third node.

35. The communications method of claim 28, further comprising:

operating the second node to receive a third signal from the third node, said received third signal authorizing the tunnel state entry information used for packet redirection; and

operating the second node to perform one of a packet buffering operation and a packet drop operation, on a received data packet that includes the first address as a destination address prior to authorization of said tunnel state entry information.

36. The communications method of claim 28, wherein said system further includes a fourth node, a third identifier being associated with the fourth node, the method further comprising:

operating said fourth node to transmit an additionally routing advertisement for the address associated with the first identifier;

operating the second node to receive a second signal further including the third identifier; and

operating the second node to store said third identifier and associate it with the tunnel state entry for the first and second identifiers.

37. The communications method of claim 28,

wherein the first identifier is one of the following identifiers associated with a mobile node:

a fully qualified domain name (FQDN), a Network Access Identity (NAI), a SIP Universal Resource Identifier (URI), an identifier derived from an International Mobile Subscriber Identity (IMSI), a globally unique end node identifier; and

wherein the second identifier is one of the following identifiers associated with an access node;

a FQDN, an NAI, and a private access node identifier assigned by the operator.