Active multicast information protocol

• US 20060159091A1
• Filed: 01/19/2005
• Published: 07/20/2006
• Est. Priority Date: 01/19/2005
• Status: Abandoned Application

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Boers, Arjen, Wijnands, Ijsbrand
• Application Number:
  US11/038,437
• Publication Number:
  US 20060159091A1
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

In the disclosed active multicast information protocol, a first edge router of a network receives a data packet from a source, wherein the data packet comprises data to be sent to receivers of a multicast group. The first edge router may rout the data packet to a first core router within the network. The first edge router also generates a message in response to receiving the data packet. This message is transmitted to the first core router within a network. The message includes an address of the source, but the message lacks data to be transmitted to the receivers of the multicast group. Another edge router stores the first multicast group and source addresses in an entry of a look-up table (LUT) in response to the edge router receiving a first message directly or indirectly from the first edge router.

Claims

1. A method comprising:

a first edge router receiving a data packet from a source, wherein the data packet comprises data to be sent to receivers of a multicast group;

the first edge router routing the data packet to a first core router;

the first edge router generating a message in response to receiving the data packet;

the first edge router transmitting the message to the first core router within a network;

wherein the message comprises an address of the source, and;

wherein the message lacks data to be transmitted to the receivers of the multicast group.

2. The method of claim 1 wherein the message comprises an address of the multicast group.

3. The method of claim 2 further comprising:

the first core router receiving the message;

the first core router forwarding the message directly or indirectly to a second edge router;

the second edge router storing the source address and multicast group address of the received message into an entry of a table in memory in response to the second edge router receiving the message directly or indirectly from the first core router.

4. The method of claim 3 further comprising:

the second edge router receiving an IGMP report from a device, wherein the IGMP report comprises the address of the multicast group;

the second edge router accessing the table using the address of the multicast group;

the table returning the address of the source in response to the second edge router accessing the table;

creating a source specific multicast tree to the source identified by the source address returned from the table.

5. The method of claim 3 further comprising:

the second edge router receiving an IGMP membership report from a device, wherein the IGMP report comprises the address of the multicast group;

the second edge router accessing the table using the address of the multicast group;

the table returning the address of the source in response to the second edge router accessing the table;

the second edge router generating and transmitting a PIM request to join the multicast group identified by the multicast group address in response to the table returning the address of the source;

wherein the PIM request comprises the addresses of the multicast group and the source.

6. The method of claim 5 further comprising:

the second edge router receiving a second IGMP membership report from a second device, wherein the second IGMP report comprises an address of a second multicast group;

the second edge router accessing the table using the address of the second multicast group;

the table returning an address of a second source in response to the second edge router accessing the table using the address of the second multicast group;

the second edge router generating and transmitting a second PIM request to join the second multicast group identified by the second multicast group address in response to the table returning the address of the second source;

wherein the second PIM request comprises the addresses of the second multicast group and the source.

7. The method of claim 1 further comprising:

the first core router forwarding the message to a second core router, in response to the first core router receiving the message from the first edge router;

the second core router core router forwarding the message to all routers directly coupled thereto, except the first core router, in response to the second core receiving the message from the first core router.

8. The method of claim 1 wherein the first edge router is in data communication with the first core router via a wireless communication link.

9. The method of claim 3 further comprising an act of removing or invalidating the entry from the table after the source stops transmitting data to receivers of the multicast group.

10. The method of claim 3 wherein the message further comprises a hold time value, wherein the hold time value defines a length of time the entry is stored in the table before being removed therefrom or before being invalidated therein.

11. The method of claim 1 wherein the message further comprises a data transmission rate value, wherein the data transmission rate value defines a rate at which the source will transmit data to receivers of the multicast group.

12. The method of claim 7 wherein the message further comprises a table distinguisher value, wherein the table distinguisher value identifies which of a plurality of routing tables in one of the first core router and second core router, is to be used when routing data packets generated by the source.

13. The method of claim 1 wherein the message further comprises an MDT group identity value, wherein the MDT group identity is used by the second core router to select one of a plurality of MDT groups in order to receive specific tunnel multicast data from the source.

31. The computer readable medium of claim 7 wherein the message further comprises a table distinguisher value, wherein the table distinguisher value identifies which of a plurality of routing tables in the first core router is to be used when routing data packets generated by the source.

14. An apparatus comprising:

a first edge router configured to receive a data packet from a source, wherein the data packet comprises data to be sent to receivers of a multicast group, wherein the first edge router is configured to rout the data packet to a first core router, wherein the first edge router comprises;

one or more microprocessors coupled to a memory configured to store instructions executable by the one or more processors, wherein the one or more processors are configured to implement a method in response to executing the instructions, the method comprising;

generating a message in response to the first edge router receiving the data packet;

transmitting the message to the first core router;

wherein the message comprises an address of the source, and;

wherein the message lacks data to be transmitted to the receivers of the multicast group.

15. The apparatus of claim 14 wherein the message comprises an address of the multicast group.

16. The apparatus of claim 14 further comprising:

the first core router, wherein the first core router is configured to receive the message, wherein the first core router is configured to forward the message directly or indirectly to a second edge router;

the second edge router, wherein the second core router comprises a table for storing entries, wherein each entry comprises source and multicast group addresses, wherein the second edge router is configured to store the source address and multicast group address of the received message into an entry of the table in response to the second edge router receiving the message directly or indirectly from the first core router.

17. The apparatus of claim 16 wherein:

the second edge router is configured to receive an IGMP report from a device, wherein the IGMP report comprises the address of the multicast group;

the second edge router is configured to access the table using the address of the multicast group;

the table is configured to return the address of the source in response to the second edge router accessing the table;

the second edge router is configured to initiate creation of a source specific multicast tree to the source identified by the source address returned from the table.

18. The apparatus of claim 16 wherein:

the second edge router is configured to receive an IGMP membership report from a device, wherein the IGMP report comprises the address of the multicast group;

the second edge router is configured to access the table using the address of the multicast group;

the table is configured to return the address of the source in response to the second edge router accessing the table;

the second edge router is configured to generate and transmit a PIM request to join the multicast group identified by the multicast group address in response to the table returning the address of the source, wherein the PIM request comprises the addresses of the multicast group and the source.

19. The apparatus of claim 18 further wherein:

the second edge router is configured to receive a second IGMP membership report from a second device, wherein the second IGMP report comprises an address of a second multicast group;

the second edge router is configured to access the table using the address of the second multicast group;

the table is configured to return an address of a second source in response to the second edge router accessing the table using the address of the second multicast group;

the second edge router is configured to generate and transmit a second PIM request to join the second multicast group identified by the second multicast group address in response to the table returning the address of the second source, wherein the second PIM request comprises the addresses of the second multicast group and the source.

20. The apparatus of claim 14 wherein the first edge router is coupled to a network, wherein the network lacks a rendezvous point router.

21. The method of claim 14 wherein the first edge router is in data communication with the first core router via a wireless communication link.

22. The apparatus of claim 16 wherein the second edge router is configured to remove or invalidate the entry from the table after the source stops transmitting data to receivers of the multicast group.

23. The apparatus of claim 16 wherein the message further comprises a hold time value, wherein the hold time value defines a length of time the entry is stored in the table before being removed therefrom or before being invalidated therein.

24. The apparatus of claim 14 wherein the message further comprises a data transmission rate value, wherein the data transmission rate value defines a rate at which the source will transmit data to receivers of the multicast group.

25. The apparatus of claim 14 wherein:

the first core router is configured to forward the message to a second core router coupled to the first core router, in response to the first core router receiving the message from the first edge router;

the second core router core router is configured to forward the message to all routers directly coupled thereto, except the first core router, in response to the second core receiving the message from the first core router.

26. The apparatus of claim 25 wherein the message further comprises a table distinguisher value, wherein the table distinguisher value identifies which of a plurality of routing tables in one of the first core router and the second core router is to be used when routing data packets generated by the source.

27. A computer readable medium that stores instructions executable by one or more processors of a first edge router within a network, wherein the one or more processors implement a method in response to executing the instructions, the method comprising:

routing a data packet to a first core router in response to the first edge router receiving the data packet from a source, wherein the data packet comprises data to be sent to receivers of a multicast group;

generating a message in response to the first edge router receiving the data packet;

transmitting the message to the first core router;

wherein the message comprises an address of the source, and;

wherein the message lacks data to be transmitted to the receivers of the multicast group.

28. The computer readable medium of claim 27 wherein the message comprises an address of the multicast group.

29. The computer readable medium of claim 28 wherein the message further comprises a hold time value, wherein the hold time value defines a length of time a table in a second edge router stores an entry, before the entry is removed therefrom or before the entry is invalidated therein, wherein the entry comprises the source and multicast group addresses.

30. The computer readable medium of claim 27 wherein the message further comprises a data transmission rate value, wherein the data transmission rate value defines a rate at which the source will transmit data to receivers of the multicast group.

32. The computer readable medium of claim 27 wherein the message further comprises an MDT group identity value, wherein the MDT group identity is used by the first core router to select one of a plurality of MDT groups in order to receive specific tunnel multicast data from the source.

33. An apparatus comprising:

a first edge router for receiving a data packet from a source, wherein the data packet comprises data to be sent to receivers of a multicast group;

means for routing the data packet to a first core router;

means for generating a message in response to receiving the data packet;

means for transmitting the message to the first core router within a network;

wherein the message comprises an address of the source, and;

wherein the message lacks data to be transmitted to the receivers of the multicast group.

34. The apparatus of claim 33 wherein the message comprises an address of the multicast group.

35. The apparatus of claim 34 further comprising:

the first core router, wherein the first core router is configured to receive the message;

means, contained in the first core router, for forwarding the message directly or indirectly to a second edge router;

means for storing the source address and multicast group address of the forwarded message into an entry of a table in memory in response to the second edge router receiving the message directly or indirectly from the first core router.

36. -69. (canceled)