Method and apparatus for automatic inter-domain routing of calls

• US 7,457,290 B1
• Filed: 04/29/2003
• Issued: 11/25/2008
• Est. Priority Date: 08/25/1998
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Oran, David R., Salama, Hussein Farouk, Shah, Dhaval N.
• Primary Examiner(s): Pham; Chi H.
• Assistant Examiner(s): Phan; Tri H.
• Application Number:
  US10/426,459
• Time in Patent Office: 2,037 Days
• Field of Search: 370352-356, 370/401, 370/410, 3703952-39521, 370/522, 370/351, 370/389, 370/392, 370/400
• US Class Current: 370/392
• CPC Class Codes: H04L 12/2856 Access arrangements, e.g. Internet access asynchronous transfer mode networks H04L12/5601; broadband local area networks H04L12/2801; optical access or distribution networks H04Q11/0067; access to open networks H04L12/5691; digital subscriber line end-user equipment and bit-level processing of data on a PSTN-based network H04M11/00; home network gateways H04L12/2834; wireless access networks H04W
• CPC Class Codes: H04L 12/2898 Subscriber equipments DSL modems H04M11/062; cable modems H04L12/2801
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/033 by updating distance vector protocols
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• CPC Class Codes: H04L 65/1106 Call signalling protocols; H.323 and related
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 7/1285 Details of finding and selecting a gateway for a particular call

Abstract

A method and apparatus for inter-domain routing of calls in a network, where the network represents a first wide area network. A routing node of the network advertises its access to a range of addresses in a second wide area network and a cost for access to the range of addresses to all adjacent nodes in the network. Each of the adjacent nodes inserts an entry in its own routing table associating access to the range of addresses in the second wide area network with the network address of the routing node and the cost for access. Each adjacent node then modifies the cost for access by adding its own cost and advertises its access to the range of addresses in the second wide area network and the modified cost for access to all of its adjacent nodes. When a call addressed to a destination address in the range of address in the second wide area network is received at each node of the network, then the node searches for the entry in its routing table corresponding to the range of addresses in the second wide area network having the lowest cost for access and connects the call to the adjacent node associated with the entry having the lowest cost. The routing node can also advertise one or more protocol types which it can support, where the protocol types are associated with the routing node in the routing table in each adjacent node and a call having a given protocol type is also routed at each node of the network based upon its protocol type.

Claims

1. A device to establish an IP phone call, comprising:

a processor configured to send and receive IP call routing update messages to establish the IP phone call over an IP network, the routing update messages including both network layer addresses to identify next hops in the IP network and application layer addresses to identify phone prefixes accessible from the next hops; and

a routing table comprising a plurality of entries and enabled to store information from at least some of the received routing update messages.

2. The call establishing device according to claim 1 wherein the routing update messages include communication protocols supported by the next hops.

3. The call establishing device according to claim 2 wherein the protocols include H.323, Session Initiation Protocol (SIP), Q.931, or Plain Old Telephone Service (POTS).

4. The call establishing device according to claim 1 wherein the network layer addresses are layer 3 IP addresses of the Open System Interconnection (OSI) model and the application layer addresses are layer 7 addresses of the OSI model.

5. The call establishing device according to claim 1 wherein the processor is enabled to use the entries of the routing table to establish call legs for the IP phone call.

6. The call establishing device according to claim 1 wherein the processor is enabled to receives IP phone call signaling protocols in the routing update messages and is enabled to uses one of the protocols associated with an identified one of the next hops to establish a call leg in the IP phone call.

7. The call establishing device according to claim 1 wherein the processor is enabled to selects one of the next hops according to cost values contained in the routing date messages.

8. The call processing establishing device according to claim 1 wherein the processor is enabled to assigns local preference values to the network layer addresses and is enabled to selects one of the next hops according to the local preference values.

9. A method to establish an Internet Protocol (IP) call connection over a network, comprising:

dynamically receiving IP call routing update messages from one or more next hops in the IP network, the IP call routing update messages including destination phone numbers accessible from the next hops and associated IP network layer addresses for the next hops;

receiving a called phone number;

selecting one of the next hops with the accessible destination phone numbers corresponding to the called phone number; and

using the IP network layer address associated with the selected next hop to establish a call leg of the IP call connection for the called phone number.

10. The method according to claim 9 including automatically exchanging the routing update messages between multiple network processing devices in the network and then establishing multiple call legs for the called phone number over the network according to the exchanged routing update messages.

11. The method according to claim 9 including:

receiving protocol identifiers in the routing update messages identifying IP call signaling protocols supported by the next hops; and

selecting one of the next hops according to the protocol identifiers.

12. The method according to claim 9 including:

storing the received routing update messages in a local routing table;

automatically modifying the received routing update messages by replacing the IP network layer addresses for the next hops with a local IP network layer address; and

advertising the modified routing update messages to neighboring network processing devices in the network.

13. The method according to claim 12 including identifying locally supported IP call signaling protocols in the modified routing update messages.

14. The method according to claim 12 including incrementing cost values in the received routing update messages and sending the incremented cost values in the modified routing update messages.

15. The method according to claim 9 including selecting one of the next hops according to cost values contained in the routing update messages.

16. The method according to claim 9 including:

assigning local preferences to the next hops;

identifying multiple next hops having the accessible destination phone numbers corresponding with the called phone number; and

selecting one of the identified next hops with a highest one of the local preferences as the call leg of the IP call connection.

17. A system for establishing an Internet Protocol (IP) call connection over a network, comprising:

means for dynamically receiving IP call routing messages from one or more next hops in the IP network, the IP call routing messages including destination phone numbers accessible from the next hops and associated IP network layer addresses for the next hops;

means for receiving a called phone number;

means for selecting one of the next hops with a destination phone number corresponding to the called phone number; and

means for using the IP network layer address associated with the selected next hop to establish a call leg of the IP call connection for the called phone number.

18. The system according to claim 17 including:

means for automatically exchanging the routing messages between multiple network processing devices in the network; and

means for establishing multiple call legs for the called phone number over the network according to the exchanged routing messages.

19. The system according to claim 17 including:

means for receiving protocol identifiers in the routing messages identifying IP call signaling protocols supported by the next hops; and

means for selecting one of the next hops according to the protocol identifiers.

20. The system according to claim 17 including:

means for storing the received routing messages in a local routing table;

means for automatically modifying the received routing messages by replacing the IP network layer addresses for the next hops with a local IP network layer address; and

means for advertising the modified routing messages to neighboring network processing devices in the network.

21. The system according to claim 20 including means for identifying locally supported IP call signaling protocols in the modified routing messages.

22. The system according to claim 20 including means for incrementing a cost values in the received routing messages and sending the incremented cost values in the modified routing messages.

23. The system according to claim 17 including means for selecting one of the next hops according to cost values contained in the routing messages.

24. The system according to claim 17 including:

means for assigning local preferences to the next hops;

means for identifying multiple next hops having the destination phone numbers corresponding with the called phone number; and

means for selecting one of the identified next hops with a highest one of the local preferences as the call leg of the IP call connection.