PIM fast failover using PIM graft message

1. A system for Protocol Independent Multicast (PIM) fast failover recovery, the system comprising:

a network comprising a plurality of switching devices, the plurality of switching devices comprising a source switching device near a source communicatively connected to a receiver switching device near a receiver by a first interface, and a third switching device communicatively connected to the receiver switching device by a second interface and communicatively connected to the source switching device by a third interface, and further comprises a fourth switching device communicatively connected to the receiver switching device by a fourth interface and communicatively connected to the source switching device by a fifth interface;

wherein after the receiver switching device discovers the first interface has failed, the receiver switching device sends the third switching device and the fourth switching device a bulk graft PIM message comprised of a group of PIM graft messages prior to deleting an associated first interface route entry, and

wherein after the third switching device receives the bulk graft PIM message from the receiver switching device via the second interface, the third switching device requests data traffic from the source switching device via the third interface.

2. The system of claim 1 wherein the receiver switching device discards the forwarded data traffic from the third switching device and the fourth switching device until the receiver switching device determines a best route.

3. The system of claim 2 wherein the receiver switching device routes the forwarded data traffic from either the third switching device or the fourth switching device that is associated with the best route to the receiver.

4. A method for Protocol Independent Multicast (PIM) fast failover recovery, the method comprising:

determining, with a receiver switching device nearest a receiver, that a first interface that communicatively connects the receiver switching device to a source switching device nearest a source has failed;

sending, with the receiver switching device, a bulk graft PIM message comprised of a group of PIM graft messages to a third switching device communicatively connected to the receiver switching device by a second interface and communicatively connected to the source switching device by a third interface, and to a fourth switching device communicatively connected to the receiver switching device by a fourth interface and communicatively connected to the source switching device by a fifth interface;

subsequent to sending the bulk graft PIM message, deleting an associated first interface route entry with the receiver switching device;

after the third switching device receives the bulk graft PIM message from the receiver switching device, requesting, via the third switching device and the third interface, data traffic from the source switching device; and

after the third switching device receives the data traffic from the source switching device, setting, via the third switching device, the second interface to a forwarding state and forwarding the data traffic to the receiver switching device via the second interface.

5. The method of claim 4 further comprising:

discarding, with the receiver switching device, the forwarded data traffic from the third switching device and the fourth switching device.

6. The method of claim 5 , further comprising:

determining, with the receiver switching device, a best route chosen from a first route from the receiver switching device to the source switching device via the third switching device or from a second route from the receiver switching device to the source switching device via the fourth switching device.

7. The method of claim 6 , further comprising:

routing to the receiver, with the receiver switching device, the forwarded data traffic from either the third switching device or the fourth switching device that is associated with the best route.

8. A computer program product for Protocol Independent Multicast (PIM) fast failover recovery, the computer program product comprising a hardware computer readable storage device having program code embodied therewith, the program code executable to:

determine, with a receiver switching device nearest a receiver, that a first interface that communicatively connects the receiver switching device to a source switching device nearest a source has failed;

send, with the receiver switching device, a bulk graft PIM message to a third switching device communicatively connected to the receiver switching device by a second interface and communicatively connected to the source switching device by a third interface, and to a fourth switching device communicatively connected to the receiver switching device by a fourth interface and communicatively connected to the source switching device by a fifth interface;

delete an associated first interface route entry, with the receiver switching device, subsequent to sending the bulk graft PIM message;

request data traffic from the source switching device, via the third switching device and the third interface, after the third switching device receives the bulk graft PIM message from the receiver switching device via the second interface; and

request data traffic from the source switching device, via the fourth switching device and the fifth interface, after the fourth switching device receives the bulk graft PIM message from the receiver switching device via the fourth interface.

9. The computer program product of claim 8 wherein the program code is further executable to:

receive, with the third switching device, the bulk graft PIM message from the receiver switching device, and;

request, with the third switching device, data traffic from the source switching device.

10. The system of claim 1 , wherein the first interface connects the source switching device and the receiver switching device without requiring a connection through either the third or fourth switching devices.

11. The system of claim 1 , wherein after the fourth switching device receives the bulk graft PIM message from the receiver switching device, the fourth switching device requests data traffic from the source switching device.

12. The system of claim 11 , wherein after the third switching device receives the data traffic from the source switching device, the third switching device sets the second interface to a forwarding state and forwards the data traffic to the receiver switching device via the second interface.

13. The system of claim 12 , and after the fourth switching device receives the data traffic from the source switching device, the fourth switching device sets the fourth interface to a forwarding state and forwards the data traffic received from the source switching device to the receiver switching device via the fourth interface.

14. The method of claim 4 , wherein, after the fourth switching device receives the bulk graft PIM message from the receiver switching device, requesting, via the fourth switching device, data traffic from the source switching device, and, after the fourth switching device receives the data traffic from the source switching device, setting, via the fourth switching device, the fourth interface to a forwarding state and forwarding the data traffic received from the source switching device to the receiver switching device via the fourth interface.

15. The computer program product of claim 8 wherein the program code is further executable to:

set the second interface to a forwarding state and forward the data traffic to the receiver switching device via the second interface when the third switching device receives the data traffic from the source switching device; and

set the fourth interface to a forwarding state and forward the data traffic received from the source switching device to the receiver switching device via the fourth interface when the fourth switching device receives the data traffic from the source switching device.