Establishing bi-directional communication sessions across a communications network

• US 6,680,943 B1
• Filed: 10/01/1999
• Issued: 01/20/2004
• Est. Priority Date: 10/01/1999
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Stacey, David, Gibson, Mark Robert
• Primary Examiner(s): Rao, Seema S.
• Assistant Examiner(s): Jagannathan, Melanie
• Application Number:
  US09/410,317
• Time in Patent Office: 1,572 Days
• Field of Search: 370/238, 370/238.1, 370/352, 370/389, 370/392, 370/393, 370/395.21, 370/395.3, 370/395.31, 370/395.5, 370/395.52, 370/400, 370/401, 370/410, 370/469
• US Class Current: 370/392
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 65/1043 Gateway controllers, e.g. media gateway control protocol [MGCP] controllers
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1094 Inter-user-equipment sessions transfer or sharing
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

On receipt of a request for a communication session over a communications network, such as an Internet Protocol communications network, a path for the session is established. In a preferred example the communications network is an MPLS network and the method uses a modified version of the SIP messaging protocol. Bandwidth along a chosen path is reserved and a messaging protocol such as CR-LDP used to establish this reserved path for the communication session. Internet protocol and MPLS communications networks typically only support uni-directional flows. Several methods for establishing bi-directional communication sessions over internet protocol communications networks that use MPLS connections are described. This is particularly useful for telephony applications using internet protocol communications networks. In a preferred example, the established connection provides a guaranteed level of quality of service.

Claims

1. A method of establishing a bi-directional communication session between a first endpoint and a second endpoint in a communications network, said method comprising the steps of:

(i) sending a communication from said second endpoint to said first endpoint to determine a path between said second and said first endpoints;

(ii) sending a first message along said path in order to set up a first label mapping along said path, for use over said path in a forward direction; and

concurrently sending a second message along said path in order to set up a second label mapping along said path, for use over said path in a reverse direction.

2. A method as claimed in claim 1 wherein said first and second messages are sent along said path in opposite directions.

3. A method as claimed in claim 1 wherein said communication session is provided with a specified level of quality of service.

4. A method as claimed in claim 1 wherein said communications network is an internet protocol communications network.

5. A method as claimed in claim 1 wherein said communication session is suitable for provision of telephony services.

6. A method as claimed in claim 1 wherein said communications network comprises a plurality of nodes interconnected by links and wherein said communications network is configured such that a plurality of said links are of a specified capacity.

7. A method as claimed in claim 6 wherein nodes which are connected to a link of a specified capacity are arranged to advertise information about that link.

8. A method as claimed in claim 7 wherein said information comprises the source, destination and capacity of the link.

9. A method as claimed in claim 8 wherein said information comprises a label for use by a message protocol in order to traverse that link.

10. A method of establishing a bi-directional communication session between a first endpoint and a second endpoint in a communications network, said method comprising the steps of:

(i) sending a communication from said first endpoint to said second endpoint to determine a path between said endpoints;

(ii) sending a message along said path in order to set up a first label mapping along said path, for use over said path in a forward direction; and

also concurrently to set up a second label mapping along said path, for use over said path in a reverse direction.

11. A method as claimed in claim 10 wherein said communications network comprises nodes interconnected by links, and wherein said communications network is configured such that at least some of said communications links are assigned a label for a forward direction along that link and the same label for a reverse direction along that link.

12. A method as claimed in claim 10 wherein said communication session is provided with a specified level of quality of service.

13. A method as claimed in claim 10 wherein said communications network is an internet protocol communications network.

14. A method as claimed in claim 13 wherein said communication session is suitable for provision of telephony services.

15. A method as claimed in claim 10 wherein said communications network comprises a plurality of nodes interconnected by links and wherein said communications network is configured such that a plurality of said links are of a specified capacity.

16. A method as claimed in claim 15 wherein nodes which are connected to a link of a specified capacity are arranged to advertise information about that link.

17. A method as claimed in claim 16 wherein said information comprises the source, destination and capacity of the link.

18. A method as claimed in claim 16 wherein said information comprises a label for use by a message protocol in order to traverse that link.

19. A method of establishing a bi-directional communication session between a first endpoint and a second endpoint in a communications network, said method comprising the steps of:

(i) setting up first label mappings between the endpoints to establish a first uni-directional communication session between the endpoints in a forward direction;

(ii) setting up second label mappings between the endpoints to establish a second uni-directional communication session between the endpoints in a reverse direction; and

wherein said steps (i) and (ii) of establishing uni-directional communication sessions take place substantially concurrently on the same path.

20. A method as claimed in claim 19 wherein said communication session is provided with a specified level of quality of service.

21. A method as claimed in claim 19 wherein said communications network is an internet protocol communications network.

22. A method as claimed in claim 21 wherein said communication session is suitable for provision of telephony services.

23. A method as claimed in claim 19 wherein said communications network comprises a plurality of nodes interconnected by links and wherein said communications network is configured such that a plurality of said links are of a specified capacity.

24. A method as claimed in claim 24 wherein said communications network includes a plurality of nodes interconnected by links which form a physical layer of said communications network and wherein nodes in said physical layer which are connected to a link of a specified capacity are arranged to advertise information about that link.

25. A method as claimed in claim 24 wherein said information comprises the source, destination and capacity of the link.

26. A method as claimed in claim 24 wherein said information comprises a label for use by a message protocol in order to traverse that link.

27. A communications network comprising at least two endpoints between which it is desired to establish a bi-directional communication session, said communications network comprising:

(i) a determiner arranged to determine a path between said second and said first endpoints by sending a communication from said second endpoint to said first endpoint;

(ii) a processor arranged to send a first message along said path in order to set up a first label mapping along said path, for use over said path in a forward direction; and

(iii) a processor arranged to send a second message along said path in order to set up a second label mapping along said path concurrently with the first label mapping, for use over said path in a reverse direction.

28. A communications network as claimed in claim 27 which is an internet protocol communications network.

29. A communications network as claimed in claim 27 which is an MPLS communications network.

30. A communications network comprising at least two endpoints between which it is desired to establish a bi-directional communication session, said communications network comprising:

(i) a determiner arranged to determine a path between said endpoints by sending a communication from said first endpoint to said second endpoint; and

(ii) a processor arranged to send a message along said path in order to set up a first label mapping along said path, for use over said path in a forward direction; and

also concurrently to set up a second label mapping along said path, for use over said path in a reverse direction.

31. A communications network as claimed in claim 30 which is an internet protocol communications network.

32. A communications network as claimed in claim 30 which is an MPLS communications network.

33. A communications network comprising at least two endpoints between which it is desired to establish a bi-directional communication session, said communications network comprising:

(i) a processor arranged to set up first label mappings between the endpoints establish a first uni-directional communication session between the endpoints in a forward direction; and

(ii) a second processor arranged to set up second label mappings between the endpoints establish a second uni-directional communication session between the endpoints in a reverse direction; and

wherein said steps (i) and (ii) of establishing uni-directional communication sessions take place substantially concurrently on the same path.

34. A computer program stored on a computer readable medium said computer program being arranged to control said communications network such that:

(i) a communication is sent from said second endpoint to said first endpoint to determine a path between said second and said first endpoints;

(ii) a first message is sent along said path in order to set up a first label mapping along said path, for use over said path in a forward direction; and

concurrently, a second message is sent along said path in order to set up a second label mapping along said path, for use over said path in a reverse direction.

35. A computer program stored on a computer readable medium said computer program being arranged to control said communications network such that:

(i) first label mappings are set up between the endpoints to establish first uni-directional communication session between the endpoints in a forward direction;

(ii) second label mappings are set up between the endpoints to establish a second uni-directional communication session between the endpoints in a reverse direction;

and wherein said steps (i) and (ii) of establishing uni-directional communication sessions take place substantially concurrently on the same path.