Active multicast information protocol

• US 8,243,643 B2
• Filed: 01/28/2005
• Issued: 08/14/2012
• Est. Priority Date: 01/19/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Boers, Arjen, Wijnands, Ijsbrand
• Primary Examiner(s): Lim, Steven
• Application Number:
  US11/046,629
• Publication Number:
  US 20060159092A1
• Time in Patent Office: 2,755 Days
• Field of Search: 370/390, 370/312
• US Class Current: 370/312
• 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 non-transitory computer readable medium configured to store instructions executable by one or more processors in an edge router, wherein the one or more processors are configured to perform a method in response to executing the instructions, the method comprising an act of

storing 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 another edge router, wherein

the first message comprises the first multicast group and source addresses,

the first source address identifies a first source that transmits data to receivers corresponding to the first multicast group address, and

the first message indicates that the first source is active;

and

storing second multicast group and source addresses in another entry of the LUT in response to the edge router receiving a second message directly or indirectly from a third edge router, wherein

the second message comprises the second multicast group and source addresses, and

the second source address identifies a second source that transmits data to receivers corresponding to the second multicast group address.

2. The non-transitory computer readable medium of claim 1, wherein

the LUT is stored in memory within the edge router.

3. The non-transitory computer readable medium of claim 1, wherein the method further comprises an act of

removing or invalidating the entry from the LUT after the first source stops transmitting data to the receivers corresponding to the first multicast group address.

4. The non-transitory computer readable medium of claim 1, wherein the method further comprises an act of

removing or invalidating the entry from the LUT a period of time after the entry is stored in the LUT, wherein

the period of time is defined by a hold time value within the first message.

5. The non-transitory computer readable medium of claim 1, wherein

the first message further comprises a data transmission rate value, wherein

the data transmission rate value defines a rate at which the first source transmits data to the receivers corresponding to the first multicast group address.

6. A non-transitory computer readable medium configured to store instructions executable by one or more processors in an edge router, wherein the one or more processors are configured to perform a method in response to executing the instructions, the method comprising:

storing a first multicast group address and a first source address that corresponds to the first multicast group address in an entry of a look-up table (LUT) in response to the edge router receiving a first message directly or indirectly from another edge router, wherein

the first message comprises the first multicast group and source addresses,

the first source address identifies a first source that transmits data to receivers corresponding to the first multicast group address, and

the first message indicates that the first source is active;

obtaining the first source address from the LUT that corresponds to the first multicast group address in response to the edge router receiving a first IGMP membership report from a first device, wherein

the first IGMP membership report comprises the first multicast group address but does not comprise the first source address; and

generating a first PIM request to join a first multicast group identified by the first multicast group address in response to obtaining the first source address from the LUT, wherein

the first PIM request to join comprises the first source address obtained from the LUT.

7. The non-transitory computer readable medium of claim 6, wherein

the first PIM request to join further comprises the first multicast group address.

8. The non-transitory computer readable medium of claim 6, wherein the method further comprises:

receiving a second IGMP membership report from a second device, wherein

the second IGMP membership report comprises a second multicast group address;

accessing the LUT using the second multicast group address;

the LUT returning a second source address in response to accessing the LUT using the second multicast group address; and

generating and transmitting a second PIM request to join a second multicast group identified by the second multicast group address in response to the LUT returning the second source address, wherein

the second PIM request to join comprises the second multicast group address and the second source address.

9. The non-transitory computer readable medium of claim 6, wherein the LUT is stored in memory within the edge router.

10. The non-transitory computer readable medium of claim 6, wherein the method further comprises an act of

removing or invalidating the entry from the LUT after the first source stops transmitting data to the receivers corresponding to the first multicast group address.

11. The non-transitory computer readable medium of claim 6, wherein the method further comprises an act of

removing or invalidating the entry from the LUT a period of time after the entry is stored in the LUT, wherein the period of time is defined by a hold time value within the first message.

12. The non-transitory computer readable medium of claim 6, wherein

the first message further comprises a data transmission rate value, wherein the data transmission rate value defines a rate at which the first source transmits data to the receivers corresponding to the first multicast group address.

13. A method comprising:

an edge router storing 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 another edge router, wherein

the first message comprises the first multicast group and source addresses,

the first source address identifies a first source that transmits data to receivers corresponding to the first multicast group address, and

the first message indicates that the first source is active; and

the edge router storing second multicast group and source addresses in another entry of the LUT in response to the edge router receiving a second message directly or indirectly from a third edge router, wherein

the second message comprises the second multicast group and source addresses, and

the second source address identifies a second source that transmits data to receivers corresponding to the second multicast group address.

14. The method of claim 13 further comprising an act of

removing or invalidating the entry from the LUT after the first source stops transmitting data to the receivers corresponding to the first multicast group address.

15. The method of claim 13 further comprising an act of

removing or invalidating the entry from the LUT a period of time after the entry is stored in the LUT, wherein

the period of time is defined by a hold time value within the first message.

16. The method of claim 13, wherein the first message further comprises

a data transmission rate value, wherein

the data transmission rate value defines a rate at which the first source transmits data to the receivers corresponding to the first multicast group address.

17. A method comprising:

an edge router storing a first multicast group address and a first source address that corresponds to the first multicast group address in an entry of a look-up table (LUT) in response to the edge router receiving a first message directly or indirectly from another edge router, wherein

the first message comprises the first multicast group and source addresses,

the first source address identifies a first source that transmits data to receivers corresponding to the first multicast group address, and

the first message indicates that the first source is active;

the edge router obtaining the first source address from the LUT that corresponds to the first multicast group address, in response to the edge router receiving a first IGMP membership report from a first device, wherein

the first IGMP membership report comprises the first multicast group address but does not comprise the first source address; and

the edge router generating a first PIM request to join a first multicast group identified by the first multicast group address in response to obtaining the first source address from the LUT, wherein

the first PIM request to join comprises the first source address obtained from the LUT.

18. The method of claim 17, wherein

the first PIM request to join further comprises the first multicast group address.

19. The method of claim 17 further comprising:

receiving a second IGMP membership report from a second device, wherein

the second IGMP membership report comprises a second multicast group address;

accessing the LUT using the second multicast group address;

the LUT returning a second source address in response to accessing the LUT using the second multicast group address; and

generating and transmitting a second PIM request to join a second multicast group identified by the second multicast group address in response to the LUT returning the address of the second source, wherein

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

20. An apparatus comprising:

an edge router coupled to an SM network and a device;

wherein the edge router comprises one or more microprocessors and a memory for storing instructions executable by the one or more processors, wherein

the one or more processors implement a method in response to executing the instructions, the method comprising;

storing a first multicast group address and a first source address that corresponds to the first multicast group address in an entry of a look-up table (LUT) in response to the edge router receiving a first message directly or indirectly from another edge router, wherein

the first message comprises the first multicast group and source addresses,

the first source address identifies a first source that transmits data to receivers corresponding to the first multicast group address, and

the first message indicates that the first source is active;

obtaining the first source address from the LUT that corresponds to the first multicast group address, in response to the edge router receiving a first IGMP membership report from a first device, wherein

the first IGMP membership report comprises the address of the first multicast group but does not comprise the address of the first source; and

generating a PIM request to join a first multicast group identified by the first multicast group address in response to obtaining the address of the first source from the LUT.

21. The method of claim 20, wherein

the PIM request to join further comprises the first multicast group address and the first source address.

22. The method of claim 20 further comprising:

receiving a second IGMP membership report from a second device, wherein

the second IGMP membership report comprises a second multicast group address;

accessing the LUT using the second multicast group address;

the LUT returning an address of a second source in response to accessing the LUT using the second multicast group address; and

generating and transmitting a second PIM request to join a second multicast group identified by the second multicast group address in response to the LUT returning the address of the second source, wherein

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

23. The method of claim 20 further comprising an act of

removing or invalidating the entry from the LUT after the first source stops transmitting data to the receivers corresponding to the first multicast group address.

24. The method of claim 20 further comprising an act of

removing or invalidating the entry from the LUT a period of time after the entry is stored in the LUT, wherein

the period of time is defined by a hold time value within the first message.

25. The method of claim 20, wherein

the first message further comprises a data transmission rate value, wherein

the data transmission rate value defines a rate at which the first source transmits data to the receivers corresponding to the first multicast group address.

26. An apparatus comprising:

an edge router coupled to a SM network and a device;

means for storing 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 another edge router, wherein

the first message comprises the first multicast group and source addresses,

the first source address identifies a first source that transmits data to receivers corresponding to the first multicast group address, and

the first message indicates that the first source is active; and

secondary means for storing second multicast group and source addresses in another entry of the LUT in response to the edge router receiving a second message directly or indirectly from a third edge router, wherein

the second message comprises the second multicast group and source addresses, and

the second source address identifies a second source that transmits data to receivers corresponding to the second multicast group address.

27. A method comprising:

an edge router storing 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 another edge router, wherein

the first message comprises the first multicast group and source addresses,

the first source address identifies a first source that transmits data to receivers corresponding to the first multicast group address, and

the first message indicates the first source is active;

removing or invalidating the entry from the LUT upon the expiration of a period of time that begins when the entry is stored in the LUT, wherein

the period of time is defined by a hold time value within the first message; and

the edge router storing second multicast group and source addresses in another entry of the LUT in response to the edge router receiving a second message directly or indirectly from a third edge router, wherein

the second message comprises the second multicast group and source addresses,

the second source address identifies a second source that transmits data to receivers corresponding to the second multicast group address.

28. The method of claim 27 further comprising an act of

removing or invalidating the second entry from the LUT after the second source stops transmitting data to the receivers corresponding to the second multicast group address.

29. The method of claim 27, wherein the first message further comprises

a data transmission rate value, wherein

the data transmission rate value defines a rate at which the first source transmits data to the receivers corresponding to the first multicast group address.