Multicast system for forwarding desired multicast packets in a computer network

• US 20050157741A1
• Filed: 09/10/2004
• Published: 07/21/2005
• Est. Priority Date: 10/16/2000
• Status: Active Grant

• Current Assignee: Ishan Wu, Nagarani Chandika, Ramana Mellacheruva, Yiqun Cai
• Original Assignee: Ishan Wu, Nagarani Chandika, Ramana Mellacheruva, Yiqun Cai
• Inventors: Cai, Yiqun, Wu, Ishan, Chandika, Nagarani, Mellacheruva, Ramana
• Granted Patent: US 7,385,977 B2
• Time in Patent Office: Days
• US Class Current: 370/432
• CPC Class Codes: H04L 12/185 with management of multicast group membership

Abstract

A method and apparatus for a downstream router to inform an upstream router by use of packets of a new router command protocol that the upstream router is to forward multicast packets of a specified group to the downstream router. First the downstream router transmits a HELLO packet to upstream router to inform the upstream router that the downstream router is a multicast router implementing the invention. Then, in the event that the downstream router receives a packet from an end station requesting multicast packets of a particular group, in response the downstream router sends a JOIN packet to the upstream router. The JOIN packet requests that the upstream router forward the requested group multicast packets to the downstream router. When a multicast group packet arrives at the upstream router, the upstream router forwards the packet to those downstream routers requesting that group.

Claims

1. A method for operating an upstream router transmitting multicast packets, comprising:

receiving a HELLO message from a downstream router, said downstream router connected to a port of said upstream router, said HELLO message received from the downstream router at said port, and in response to said HELLO message halting transmission of multicast messages through said port by said upstream router;

receiving through said port a JOIN message specifying a multicast group, and in response to said JOIN message transmitting multicast messages of said group through said port;

receiving through said port a LEAVE message specifying said group, and in response to said LEAVE message halting transmission of multicast messages for said group through said port;

receiving through said port a BYE message, and in response to said BYE message transmitting all multicast messages received by said upstream router through said port.

3. The method as in claim 1 or claim 2, further comprising:

indicating by a type number that said HELLO message is a multicast command message.

4. The method as in claim 1 or claim 2, further comprising:

indicating by a type number of 0×

FF that said HELLO message is a multicast command message.

5. The method as in claim 1 or claim 2, further comprising:

indicating by a type number that said JOIN message is a multicast command message.

6. The method as in claim 1 or claim 2, further comprising:

indicating by a type number of 0×

FD that said JOIN message is a multicast command message.

7. The method as in claim 1 or claim 2, further comprising:

indicating by a type number that said LEAVE message is a multicast command message.

8. The method as in claim 1 or claim 2, further comprising:

indicating by a type number of 0×

FC that said LEAVE message is a multicast command message.

9. The method as in claim 1 or claim 2, further comprising:

indicating by a type number that said BYE message is a multicast command message.

10. The method as in claim 1 or claim 2, further comprising:

indicating by a type number of 0×

FE that said BYE message is a multicast command message.

11. The method as in claim 1 or claim 2, further comprising:

using as said HELLO message a RGMP HELLO message;

using as said JOIN message a RGMP JOIN message;

using as said LEAVE message a RGMP LEAVE message; and

using as said BYE message a RGMP BYE message.

2. A method for operating a downstream router receiving multicast packets, comprising:

transmitting a HELLO message out through a port connected to said upstream router in order to command said upstream router to stop forwarding multicast packets to s said downstream router;

transmitting a JOIN message specifying a multicast group out through said port in order to command said upstream router to forward multicast packets of said group to said downstream router;

transmitting a LEAVE message specifying said group in order to command said upstream router to stop forwarding multicast packets of said group to said downstream router; and

transmitting a BYE message to said upstream router in order to command said upstream router to begin forwarding all multicast packets to said downstream router.

12. An upstream router apparatus to transmit multicast packets, comprising:

a linecard and first interpretative circuits to receive a HELLO message from a downstream router, said HELLO message received at a port of said upstream router from said downstream router connected to said port, and in response to said HELLO message halting transmission of multicast messages through said port;

second interpretative circuits to receive through said port a JOIN message specifying a multicast group, and in response to said JOIN message transmitting multicast messages of said group through said port;

third interpretative circuits to receive through said port a LEAVE message specifying said group, and in response to said LEAVE message halting transmission of multicast messages for said group through said port;

fourth interpretative circuits to receive through said port a BYE message, and in response to said BYE message transmitting all multicast messages received by said upstream router through said port.

14. The apparatus as in claim 12 or claim 13, further comprising:

a type number to indicate that said HELLO message is a multicast command message.

15. The apparatus as in claim 12 or claim 13, further comprising:

a type number of 0×

FF to indicate that said HELLO message is a multicast command message.

16. The apparatus as in claim 12 or claim 13, further comprising:

a type number to indicate that said JOIN message is a multicast command message.

17. The apparatus as in claim 12 or claim 13, further comprising:

a type number of 0×

FD to indicate that said JOIN message is a multicast command message.

18. The apparatus as in claim 12 or claim 13, further comprising:

a type number to indicate that said LEAVE message is a multicast command message.

19. The apparatus as in claim 12 or claim 13, further comprising:

a type number of 0×

FC to indicate that said LEAVE message is a multicast command message.

20. The apparatus as in claim 12 or claim 13, further comprising:

a type number to indicate that said BYE message is a multicast command message.

21. The apparatus as in claim 12 or claim 13, further comprising:

a type number of 0×

FE to indicate that said BYE message is a multicast command message.

22. The apparatus as in claim 12 or claim 13, further comprising:

said HELLO message is a RGMP HELLO message;

said JOIN message is a RGMP JOIN message;

said LEAVE message is a RGMP LEAVE message; and

said BYE message is a RGMP BYE message.

13. A downstream router apparatus to receive multicast packets, comprising

a linecard and first circuits to transmit a HELLO message out through a port connected to an upstream router in order to command said upstream router to stop forwarding multicast packets to said downstream router;

second circuits to transmit a JOIN message specifying a multicast group out through said port in order to command said upstream router to forward multicast packets of said group to said downstream router;

third circuits to transmit a LEAVE message specifying said group in order to command said upstream router to stop forwarding multicast packets of said group to said downstream router;

fourth circuits to transmit a BYE message to said upstream router in order to command said upstream router to begin forwarding all multicast packets to said downstream router.

23. An upstream router apparatus to transmit multicast packets, comprising:

means for receiving a HELLO message from a downstream router, said downstream router connected to a port of said upstream router, said HELLO message received from the downstream router at said port, and in response to said HELLO message halting transmission of multicast messages through said port by said upstream router;

means for receiving through said port a JOIN message specifying a multicast group, and in response to said JOIN message transmitting multicast messages of said group through said port;

means for receiving through said port a LEAVE message specifying said group, and in response to said LEAVE message halting transmission of multicast messages for said group through said port;

means for receiving through said port a BYE message, and in response to said BYE message transmitting all multicast messages received by said upstream router through said port.

25. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number that said HELLO message is a multicast command message.

26. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number of 0×

FF that said HELLO message is a multicast command message.

27. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number that said JOIN message is a multicast command message.

28. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number of 0×

FD that said JOIN message is a multicast command message.

29. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number that said LEAVE message is a multicast command message.

30. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number of 0×

FC that said LEAVE message is a multicast command message.

31. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number that said BYE message is a multicast command message.

32. The apparatus as in claim 23 or claim 24, further comprising:

means for indicating by a type number of 0×

FE that said BYE message is a multicast command message.

33. The apparatus as in claim 23 or claim 24, further comprising:

means for using as said HELLO message a RGMP HELLO message;

means for using as said JOIN message a RGMP JOIN message;

means for using as said LEAVE message a RGMP LEAVE message; and

means for using as said BYE message a RGMP BYE message.

24. A downstream router apparatus to receive multicast packets, comprising:

means for transmitting a HELLO message out through a port connected to said upstream router in order to command said upstream router to stop forwarding multicast packets to said downstream router;

means for transmitting a JOIN message specifying a multicast group out through said port in order to command said upstream router to forward multicast packets of said group to said downstream router;

means for transmitting a LEAVE message specifying said group in order to command said upstream router to stop forwarding multicast packets of said group to said downstream router; and

means for transmitting a BYE message to said upstream router in order to command said upstream router to begin forwarding all multicast packets to said downstream router.

34. A computer readable media, comprising:

said computer readable media containing instructions for execution on a processor for the practice of a method of operating an upstream router transmitting multicast packets, the method having the steps,

receiving a HELLO message from a downstream router, said downstream router connected to a port of said upstream router, said HELLO message received from the downstream router at said port, and in response to said HELLO message halting transmission of multicast messages through said port by said upstream router;

receiving through said port a JOIN message specifying a multicast group, and in response to said JOIN message transmitting multicast messages of said group through said port;

receiving through said port a LEAVE message specifying said group, and in response to said LEAVE message halting transmission of multicast messages for said group through said port;

receiving through said port a BYE message, and in response to said BYE message transmitting all multicast messages received by said upstream router through said port.

35. A computer readable media, comprising:

said computer readable media containing instructions for execution on a processor for the practice of a method of operating a downstream router receiving multicast packets, the method having the steps,

transmitting a HELLO message out through a port connected to said upstream router in order to command said upstream router to stop forwarding multicast packets to said downstream router;

transmitting a JOIN message specifying a multicast group out through said port in order to command said upstream router to forward multicast packets of said group to said downstream router;

transmitting a LEAVE message specifying said group in order to command said upstream router to stop forwarding multicast packets of said group to said downstream router; and

transmitting a BYE message to said upstream router in order to command said upstream router to begin forwarding all multicast packets to said downstream router.

36. Electromagnetic signals propagating on a computer network, comprising:

said electromagnetic signals carrying instructions for execution on a processor for the practice of a method of operating an upstream router transmitting multicast packets, the method having the steps,

receiving a HELLO message from a downstream router, said downstream router connected to a port of said upstream router, said HELLO message received from the downstream router at said port, and in response to said HELLO message halting transmission of multicast messages through said port by said upstream router;

receiving through said port a JOIN message specifying a multicast group, and in response to said JOIN message transmitting multicast messages of said group through said port;

receiving through said port a LEAVE message specifying said group, and in response to said LEAVE message halting transmission of multicast messages for said group through said port;

receiving through said port a BYE message, and in response to said BYE message transmitting all multicast messages received by said upstream router through said port.

37. Electromagnetic signals propagating on a computer network, comprising:

said electromagnetic signals carrying instructions for execution on a processor for the practice of the method of operating a downstream router receiving multicast packets, the method having the steps,

transmitting a HELLO message out through a port connected to said upstream router in order to command said upstream router to stop forwarding multicast packets to said downstream router;

transmitting a JOIN message specifying a multicast group out through said port in order to command said upstream router to forward multicast packets of said group to said downstream router;

transmitting a LEAVE message specifying said group in order to command said upstream router to stop forwarding multicast packets of said group to said downstream router; and

transmitting a BYE message to said upstream router in order to command said upstream router to begin forwarding all multicast packets to said downstream router.