System, method and apparatus to resolve RPF-vector attribute conflicts

1. A method, comprising:

receiving, at a provider router (P-router) supporting multicast traffic, a join packet including a Reverse Path Forwarding (RPF) vector attribute identifying a proxy;

adding, at the P-router, the proxy to a proxy list;

identifying, by the P-router, the proxy as being valid if the proxy is reachable by the P-router and if a valid Protocol Independent Multicast (PIM) adjacency exists on one of the next route hops;

in the case of multiple valid proxies within the proxy list, selecting, at the P-router, one of said multiple valid proxies as a preferred proxy, where the selected preferred proxy being different than an existing proxy;

sending a join message toward the preferred proxy; and

waiting a predetermined amount of time before sending a prune message toward the existing proxy.

2. The method of claim 1 , wherein said sending the join and prune messages are parts of performing a make-before-break procedure to set up a multicast tree using the preferred proxy for the multicast traffic.

3. The method of claim 2 , wherein said make-before-break procedure comprises:

sending, via a PIM, the join message toward the preferred proxy;

waiting for the predetermined amount of time;

sending, via the PIM, the prune message toward the existing proxy; and

switching a multicast traffic RPF interface towards the preferred proxy.

4. The method of claim 1 , wherein the preferred proxy selection is made using a proxy metric associated with the proxy.

5. The method of claim 4 , wherein said proxy metric comprises one or more of an intervening hop number, a congestion level and a bandwidth level.

6. The method of claim 1 , wherein the preferred proxy selection is made using an indication of proxy load associated with the proxy.

7. The method of claim 6 , wherein said indication of proxy load comprises an Autonomous System Border Routers (ASBR) utilization level.

8. The method of claim 6 , wherein said indication of proxy load comprises a number of multicast source, groups (SGs) presently resolved by the proxy.

9. The method of claim 1 , wherein the preferred proxy selection is made using PIM neighbor address adjacency information.

10. The method of claim 9 , wherein said PIM neighbor address adjacency information comprises one of a smallest IP address of an adjacent node and a largest IP address of an adjacent node.

11. The method of claim 9 , wherein said PIM neighbor address adjacency information comprises one of a smallest link local address of an adjacent node and a largest link local address of an adjacent node.

12. The method of claim 1 , wherein the preferred proxy selection is made using an interface index mechanism.

13. The method of claim 4 , wherein if the preferred proxy selection using a proxy metric associated with the proxy results in a tie, then the preferred proxy selection is made using one or more additional metrics associated with the proxy.

14. The method of claim 4 , wherein if the preferred proxy selection using a proxy metric associated with the proxy results in a tie, then the preferred proxy selection is made using an indication of load associated with the proxy.

15. The method of claim 14 , wherein if the preferred proxy selection using an indication of load associated with the proxy results in a tie, then the preferred proxy selection is made using PIM neighbor address adjacency information.

16. The method of claim 15 , wherein if the preferred proxy selection using PIM neighbor address adjacency information results in a tie, then the preferred proxy selection is made using an interface index mechanism.

17. The method of claim 1 , wherein the preferred proxy selection is made according to a hierarchical decision tree including at least two of:

a metric associated with the proxy, an indication of load associated with the proxy, PIM neighbor address adjacency information and an interface index mechanism.

18. An apparatus, comprising a processor configured for:

receiving, at a provider router (P-router) supporting multicast traffic, a join packet including a Reverse Path Forwarding (RPF) vector attribute identifying a proxy;

adding, at the P-router, the proxy to a proxy list;

identifying, by the P-router, the proxy as being valid if the proxy is reachable by the P-router and if a valid Protocol Independent Multicast (PIM) adjacency exists on one of the next route hops;

in the case of multiple valid proxies within the proxy list, selecting, at the P-router, one of said multiple valid proxies as a preferred proxy, where the selected preferred proxy being different than an existing proxy;

sending a join message toward the preferred proxy; and

waiting a predetermined amount of time before sending a prune message toward the existing proxy.

19. A tangible and non-transient computer readable storage medium storing instructions which, when executed by a computer, adapt the operation of the computer to provide a method, comprising:

receiving, at a provider router (P-router) supporting multicast traffic, a join packet including a Reverse Path Forwarding (RPF) vector attribute identifying a proxy;

adding, at the P-router, the proxy to a proxy list;

identifying, by the P-router, the proxy as being valid if the proxy is reachable by the P-router and if a valid Protocol Independent Multicast (PIM) adjacency exists on one of the next route hops;

in the case of multiple valid proxies within the proxy list, selecting, at the P-router, one of said multiple valid proxies as a preferred proxy, where the selected preferred proxy being different than an existing proxy;

sending a join message toward the preferred proxy; and

waiting a predetermined amount of time before sending a prune message toward the existing proxy.

20. A non-transitory computer program product wherein computer instructions stored in a non-transitory computer readable memory, when processed by a computer, adapt the operation of the computer to provide a method, comprising:

receiving, at a provider router (P-router) supporting multicast traffic, a join packet including a Reverse Path Forwarding (RPF) vector attribute identifying a proxy;

adding, at the P-router, the proxy to a proxy list;

identifying, by the P-router, the proxy as being valid if the proxy is reachable by the P-router and if a valid Protocol Independent Multicast (PIM) adjacency exists on one of the next route hops;

in the case of multiple valid proxies within the proxy list, selecting, at the P-router, one of said multiple valid proxies as a preferred proxy, where the selected preferred proxy being different than an existing proxy;

sending a join message toward the preferred proxy; and

waiting a predetermined amount of time before sending a prune message toward the existing proxy.

21. The apparatus of claim 18 , wherein said sending the join and prune messages are parts of performing a make-before-break procedure to set up a multicast tree using the preferred proxy for the multicast traffic.

22. The tangible and non-transient computer readable storage medium of claim 19 , wherein said sending the join and prune messages are parts of performing a make-before-break procedure to set up a multicast tree using the preferred proxy for the multicast traffic.

23. The non-transitory computer program product of claim 20 , wherein said sending the join and prune messages are parts of performing a make-before-break procedure to set up a multicast tree using the preferred proxy for the multicast traffic.