Arrangement for retrieving routing information for establishing a bidirectional tunnel between a mobile router and a correspondent router

• US 20040228343A1
• Filed: 05/16/2003
• Published: 11/18/2004
• Est. Priority Date: 05/16/2003
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Thubert, Pascal, Molteni, Marco, Villari, Massimo, Wetterwald, Patrick, Levy-Abegnoli, Eric M.
• Granted Patent: US 7,886,075 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 40/28 for reactive routing
• 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 84/005 Moving wireless networks
• CPC Class Codes: H04W 88/182 Network node acting on behalf of an other network entity, e.g. proxy

Abstract

A mobile router and a correspondent router, each configured for routing services for nodes within their routing prefixes associated with their respective routing tables, establish a secure, bidirectional tunnel based on a messaging protocol between each other and a route server resource. A reactive (i.e., on-demand) protocol is used that enables the requesting device (e.g, the mobile router, correspondent router), to obtain routing information in a secure manner from the route server. The mobile router sends a query via its home agent to the route server resource to identify the correspondent router serving the correspondent node. The mobile router sends a binding update request, specifying a home address and care-of address for the mobile router, to the correspondent router for establishment of a bidirectional tunnel. The correspondent router establishes the bidirectional tunnel, and updates its routing tables based on information from the route server resource.

Claims

1. A method in an Internet Protocol (IP) based mobile router configured for sending packets to a correspondent node, the method comprising:

receiving a packet destined for IP address of the correspondent node;

determining a host domain name associated with the IP address by requesting a reverse lookup of the IP address from a name server;

identifying an authoritative name server for the host domain name based on sending a query, specifying the host domain name, to a root name server configured for identifying a top-level authoritative name server, and sending a second query, specifying the host domain name, to the top-level authoritative name server;

sending to the authoritative name server a request for identifying a correspondent router configured for establishing a tunnel for the host domain name; and

initiating establishment of the tunnel with the correspondent router for sending packets to the correspondent node.

2. The method of claim 1, wherein the sending step includes sending a second request for identifying an address prefix for the correspondent node that is reachable by the correspondent router, the method further including updating a routing table with the address prefix, received from the authoritative name server, for reaching additional nodes within a subnetwork specified by the via the tunnel.

3. The method of claim 2, wherein the sending step includes:

specifying in the request a first resource record type configured for specifying correspondent routers configured for establishing the tunnel according to a prescribed mobile network protocol; and

specifying in the second request a second resource record type configured for specifying the address prefix for the correspondent node according to the prescribed mobile network protocol.

4. The method of claim 2, wherein the sending step includes:

sending the request to a first prescribed subdomain of the authoritative name server associated with identification of correspondent routers configured for establishing the tunnel according to a prescribed mobile network protocol;

sending the second request to a second prescribed subdomain of the authoritative name server associated with identification of address prefixes for identified nodes.

5. The method of claim 1, wherein the identifying step includes recursively sending the host name, following receiving a reply to the second query that specifies an identified name server, to successively identified name servers for identification of the authoritative name server.

6. The method of claim 1, wherein:

the determining step includes sending a query, specifying the reverse lookup, via a home tunnel terminated by a home agent, and

the initiating step includes;

(1) sending a binding update request to the correspondent router via a unidirectional tunnel to the correspondent router, the binding update request specifying a corresponding home address providing reachability to the mobile router via the home agent, a corresponding care-of address providing reachability to the mobile router via an attachment router, and a mobile router flag specifying that the binding update request was generated by a router that is mobile, and

(2) validating for the correspondent router that the home address is reachable via the care-of address.

7. A method in an Internet Protocol (IP) based router configured for sending and receiving packets for a correspondent node, the method comprising:

establishing a bidirectional tunnel with a mobile router based on receiving a binding update that specifies a home address for the mobile router and a care-of address that specifies a point of attachment for the mobile router;

determining a domain name associated with the home address by requesting a reverse lookup of the home address from a name server;

identifying an authoritative name server for the domain name based on sending a query, specifying the domain name, to a root name server configured for identifying a top-level authoritative name server, and sending a second query, specifying the domain name, to the top-level authoritative name server;

sending to the authoritative name server a request for identifying at least one address prefix reachable via the mobile router; and

updating an internal routing table to indicate the at least one address prefix is reachable via the bidirectional tunnel.

8. The method of claim 7, wherein the sending step includes specifying within the request the address prefix for a mobile node having sent a packet to the correspondent node and being reachable via the mobile router, the updating step including updating the internal routing table to indicate the address prefix for the mobile node is reachable via the bidirectional tunnel.

9. The method of claim 8, wherein the sending step further includes specifying in the request a first resource record type configured for specifying the prefix for a specified mobile node and assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

10. The method of claim 8, wherein the sending step further includes sending the request to a prescribed subdomain of the authoritative name server associated with identification of an address prefix for a specified mobile node and assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

11. The method of claim 7, wherein the sending step includes specifying within the request all address prefixes reachable via the mobile router, the updating step including updating the internal routing table to indicate said all address prefixes are reachable via the bidirectional tunnel.

12. The method of claim 11, wherein the sending step further includes specifying in the request a first resource record type configured for specifying all prefixes assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

13. The method of claim 11, wherein the sending step further includes sending the request to a prescribed subdomain of the authoritative name server associated with identification of all address prefixes assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

14. A computer readable medium having stored thereon sequences of instructions for sending packets to a correspondent node by an Internet Protocol (IP) based mobile router, the sequences of instructions including instructions for:

receiving a packet destined for IP address of the correspondent node;

determining a host domain name associated with the IP address by requesting a reverse lookup of the IP address from a name server;

identifying an authoritative name server for the host domain name based on sending a query, specifying the host domain name, to a root name server configured for identifying a top-level authoritative name server, and sending a second query, specifying the host domain name, to the top-level authoritative name server;

sending to the authoritative name server a request for identifying a correspondent router configured for establishing a tunnel for the host domain name; and

initiating establishment of the tunnel with the correspondent router for sending packets to the correspondent node.

15. The medium of claim 14, wherein the sending step includes sending a second request for identifying an address prefix for the correspondent node that is reachable by the correspondent router, the medium further including instructions for updating a routing table with the address prefix, received from the authoritative name server, for reaching additional nodes within a subnetwork specified by the via the tunnel.

16. The medium of claim 15, wherein the sending step includes:

specifying in the request a first resource record type configured for specifying correspondent routers configured for establishing the tunnel according to a prescribed mobile network protocol; and

specifying in the second request a second resource record type configured for specifying the address prefix for the correspondent node according to the prescribed mobile network protocol.

17. The medium of claim 15, wherein the sending step includes:

sending the request to a first prescribed subdomain of the authoritative name server associated with identification of correspondent routers configured for establishing the tunnel according to a prescribed mobile network protocol;

sending the second request to a second prescribed subdomain of the authoritative name server associated with identification of address prefixes for identified nodes.

18. The medium of claim 14, wherein the identifying step includes recursively sending the host name, following receiving a reply to the second query that specifies an identified name server, to successively identified name servers for identification of the authoritative name server.

19. The medium of claim 14, wherein:

the determining step includes sending a query, specifying the reverse lookup, via a home tunnel terminated by a home agent, and

the initiating step includes;

(1) sending a binding update request to the correspondent router via a unidirectional tunnel to the correspondent router, the binding update request specifying a corresponding home address providing reachability to the mobile router via the home agent, a corresponding care-of address providing reachability to the mobile router via an attachment router, and a mobile router flag specifying that the binding update request was generated by a router that is mobile, and

(2) validating for the correspondent router that the home address is reachable via the care-of address.

20. A computer readable medium having stored thereon sequences of instructions for sending and receiving packets by an Internet Protocol (IP) based router for a correspondent node, the sequences of instructions including instructions for:

establishing a bidirectional tunnel with a mobile router based on receiving a binding update that specifies a home address for the mobile router and a care-of address that specifies a point of attachment for the mobile router;

determining a domain name associated with the home address by requesting a reverse lookup of the home address from a name server;

identifying an authoritative name server for the domain name based on sending a query, specifying the domain name, to a root name server configured for identifying a top-level authoritative name server, and sending a second query, specifying the domain name, to the top-level authoritative name server;

sending to the authoritative name server a request for identifying at least one address prefix reachable via the mobile router; and

updating an internal routing table to indicate the at least one address prefix is reachable via the bidirectional tunnel.

21. The medium of claim 20, wherein the sending step includes specifying within the request the address prefix for a mobile node having sent a packet to the correspondent node and being reachable via the mobile router, the updating step including updating the internal routing table to indicate the address prefix for the mobile node is reachable via the bidirectional tunnel.

22. The medium of claim 21, wherein the sending step further includes specifying in the request a first resource record type configured for specifying the prefix for a specified mobile node and assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

23. The medium of claim 21, wherein the sending step further includes sending the request to a prescribed subdomain of the authoritative name server associated with identification of an address prefix for a specified mobile node and assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

24. The medium of claim 20, wherein the sending step includes specifying within the request all address prefixes reachable via the mobile router, the updating step including updating the internal routing table to indicate said all address prefixes are reachable via the bidirectional tunnel.

25. The medium of claim 24, wherein the sending step further includes specifying in the request a first resource record type configured for specifying all prefixes assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

26. The medium of claim 24, wherein the sending step further includes sending the request to a prescribed subdomain of the authoritative name server associated with identification of all address prefixes assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

27. An Internet Protocol (IP) based mobile router configured for sending packets to a correspondent node, the mobile router comprising:

means for receiving a packet destined for IP address of the correspondent node;

means for determining a host domain name associated with the IP address by requesting a reverse lookup of the IP address from a name server;

means for identifying an authoritative name server for the host domain name based on sending a query, specifying the host domain name, to a root name server configured for identifying a top-level authoritative name server, and sending a second query, specifying the host domain name, to the top-level authoritative name server, the means for identifying configured for sending to the authoritative name server a request for identifying a correspondent router configured for establishing a tunnel for the host domain name; and

means for initiating establishment of the tunnel with the correspondent router for sending packets to the correspondent node.

28. The mobile router of claim 27, wherein the identifying means is configured for sending a second request for identifying an address prefix for the correspondent node that is reachable by the correspondent router, the mobile router further comprising updating a routing table with the address prefix, received from the authoritative name server, for reaching additional nodes within a subnetwork specified by the via the tunnel.

29. The mobile router of claim 28, wherein the identifying means is configured for:

specifying in the request a first resource record type configured for specifying correspondent routers configured for establishing the tunnel according to a prescribed mobile network protocol; and

specifying in the second request a second resource record type configured for specifying the address prefix for the correspondent node according to the prescribed mobile network protocol.

30. The mobile router of claim 28, wherein the identifying means is configured for:

sending the request to a first prescribed subdomain of the authoritative name server associated with identification of correspondent routers configured for establishing the tunnel according to a prescribed mobile network protocol; and

sending the second request to a second prescribed subdomain of the authoritative name server associated with identification of address prefixes for identified nodes.

31. The mobile router of claim 27, wherein the identifying means is configured for recursively sending the host name, following receiving a reply to the second query that specifies an identified name server, to successively identified name servers for identification of the authoritative name server.

32. The mobile router of claim 27, wherein:

the determining means is configured for sending a query, specifying the reverse lookup, via a home tunnel terminated by a home agent, and

the initiating means is configured for;

(1) sending a binding update request to the correspondent router via a unidirectional tunnel to the correspondent router, the binding update request specifying a corresponding home address providing reachability to the mobile router via the home agent, a corresponding care-of address providing reachability to the mobile router via an attachment router, and a mobile router flag specifying that the binding update request was generated by a router that is mobile, and

(2) validating for the correspondent router that the home address is reachable via the care-of address.

37. The router of claim 31, wherein the identifying means is configured for specifying within the request all address prefixes reachable via the mobile router, the updating means configured for updating the internal routing table to indicate said all address prefixes are reachable via the bidirectional tunnel.

38. The router of claim 37, wherein the identifying means is configured for specifying in the request a first resource record type configured for specifying all prefixes assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

39. The router of claim 37, wherein the identifying means is configured for sending the request to a prescribed subdomain of the authoritative name server associated with identification of all address prefixes assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

33. An Internet Protocol (IP) based router configured for sending and receiving packets for a correspondent node, the router comprising:

means for establishing a bidirectional tunnel with a mobile router based on receiving a binding update that specifies a home address for the mobile router and a care-of address that specifies a point of attachment for the mobile router;

means for determining a domain name associated with the home address by requesting a reverse lookup of the home address from a name server;

means for identifying an authoritative name server for the domain name based on sending a query, specifying the domain name, to a root name server configured for identifying a top-level authoritative name server, and sending a second query, specifying the domain name, to the top-level authoritative name server, the identifying means configured for sending to the authoritative name server a request for identifying at least one address prefix reachable via the mobile router; and

means for updating an internal routing table to indicate the at least one address prefix is reachable via the bidirectional tunnel.

34. The router of claim 33, wherein the identifying means is configured for specifying within the request the address prefix for a mobile node having sent a packet to the correspondent node and being reachable via the mobile router, the updating means configured for updating the internal routing table to indicate the address prefix for the mobile node is reachable via the bidirectional tunnel.

35. The router of claim 34, wherein the identifying means is configured for specifying in the request a first resource record type configured for specifying the prefix for a specified mobile node and assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.

36. The router of claim 34, wherein the identifying means is configured for sending the request to a prescribed subdomain of the authoritative name server associated with identification of an address prefix for a specified mobile node and assigned to a corresponding mobile router configured for establishing the bidirectional tunnel according to a prescribed mobile network protocol.