System and method for multicast routing using peer groups

1. A router comprising:

a control unit; and

a memory coupled to the control unit, the memory storing one or more first multicast routing entries including one or more second multicast routing entries associated with first multicast routing trees associated with the router and one or more third multicast routing entries associated with second multicast routing trees associated with a peer router, the second multicast routing trees including at least one multicast tree of which the router is not a member;

wherein the control unit is configured to:

receive a multicast packet on an input interface;

determine one or more properties of the multicast packet, the one or more properties including one or more selected from a group consisting of the input interface, a group destination address, and a source address of the multicast packet;

determine one or more first output interfaces based on the properties and the second multicast routing entries;

determine one or more second output interfaces based on the properties and the third multicast routing entries; and

forward copies of the multicast packet to each of the first and second output interfaces;

wherein the router is configured to be coupled to the peer router via an inter-chassis link (ICL).

2. The router of claim 1 wherein when the input interface is a spanned input interface, the control unit is further configured to forward an additional copy of the multicast packet to the peer router on the input interface using the ICL.

3. The router of claim 1 wherein when the multicast packet is received via the ICL, the control unit is further configured to forward the copies of the multicast packet to the first and second output interfaces that are spanned output interfaces when outgoing ports of the peer router associated with the spanned output interfaces are down.

4. The router of claim 1 wherein the second multicast routing entries are local multicast routing entries and the third multicast routing entries are synchronized multicast routing entries.

5. The router of claim 1 wherein the third multicast routing entries are associated with spanned input interfaces and spanned output interfaces.

6. The router of claim 1 wherein the control unit is further configured to:

receive one or more notifications associated with one or more multicast routing updates in the peer router; and

update the third multicast routing entries based on the second multicast routing entries and the multicast routing updates.

7. The router of claim 1 wherein the control unit is further configured to:

receive one or more multicast routing updates associated with a multicast routing protocol; and

update the first multicast routing entries based on the multicast routing updates.

8. The router of claim 7 wherein the control unit is further configured to send one or more notifications to the peer router based on the multicast routing updates.

9. The router of claim 7 wherein the control unit updates the first multicast routing entries by merging local output interfaces with synchronized output interfaces.

10. The router of claim 1 wherein the control unit is further configured to:

determine whether the peer router is down; and

when the peer router is down, delete the third multicast routing entries after a time delay.

11. A method of multicast routing, the method comprising:

receiving a multicast packet on an input interface of a router;

determining one or more properties of the multicast packet, the one or more properties including one or more selected from a group consisting of the input interface, a group destination address, and a source address of the multicast packet;

determining one or more first output interfaces based on the properties and first multicast routing entries associated with first multicast routing trees associated with the router;

determining one or more second output interfaces based on the properties and second multicast routing entries associated with second multicast routing trees associated with a peer router coupled to the router via an inter-chassis link (ICL), the second multicast routing trees including at least one multicast tree of which the router is not a member; and

forwarding copies of the multicast packet to each of the first and second output interfaces.

12. The method of claim 11 , further comprising forwarding an additional copy of the multicast packet to the peer router on the input interface using the ICL when the input interface is a spanned input interface.

13. The method of claim 11 , further comprising forwarding the copies of the multicast packet to the first and second output interfaces that are spanned output interfaces when outgoing ports of the peer router associated with the spanned output interfaces are down and the multicast packet is received via the ICL.

14. The method of claim 11 , further comprising:

receiving one or more notifications associated with one or more multicast routing updates in the peer router; and

updating the second multicast routing entries based on the first multicast routing entries and the multicast routing updates.

15. The method of claim 11 , further comprising:

receiving one or more multicast routing updates associated with a multicast routing protocol; and

updating the first and second multicast routing entries based on the multicast routing updates.

16. The method of claim 15 , further comprising sending one or more notifications to the peer router based on the multicast routing updates.

17. An information handling system comprising:

a peer group comprising:

a first router comprising a control unit and a memory coupled to the control unit, the memory storing one or more first multicast routing entries;

a second router; and

an inter-chassis link (ICL) coupling the first router and the second router;

wherein the control unit is configured to:

receive a multicast packet on an input interface;

determine one or more properties of the multicast packet, the one or more properties including one or more selected from a group consisting of the input interface, a group destination address, and a source address of the multicast packet;

determine one or more first output interfaces based on the properties and one or more first multicast routing entries associated with first multicast routing trees associated with the first router;

determine one or more second output interfaces based on the properties and second multicast routing entries associated with second multicast routing trees associated with the second router, the second multicast routing trees including at least one multicast tree of which the first router is not a member;

forward first copies of the multicast packet to each of the first and second output interfaces; and

forward a second copy of the multicast packet to the second router on the input interface using the ICL when the input interface is a spanned input interface.

18. The information handling system of claim 17 wherein when the multicast packet is received via the ICL, the control unit is further configured to forward the first copies of the multicast packet to the first and second output interfaces that are spanned output interfaces when outgoing ports of the second router associated with the spanned output interfaces are down.

19. The information handling system of claim 17 wherein the control unit is further configured to:

receive one or more first multicast routing updates associated with a multicast routing protocol;

update the first and second multicast routing entries based on the first multicast routing updates;

send one or more notifications to the second router based on the first multicast routing updates;

receive one or more notifications associated with one or more second multicast routing updates in the second router; and

update the second multicast routing entries based on the first multicast routing entries and the second multicast routing updates.