prune message on LAN and timer , ip pim

[sarahr202]

Hi everybody.

I was reading about the override prune message or joint message.

Please consider the following example:

R1 f0-------------Sw------------------R2---H2 ( 224.7.7.7)

                           |

                           |

                           |

                          R3---H3( 224.7.7.7)

R1 forwards multicast packets 224.7.7.7 onto LAN. Let suppose H2 leaves the multicast group 224.7.7.7

According to my book, following will occur:

1) R2 sends a prune message at 224.0.0.13

2) Both R1 and R3 receives the prune message.

3) R1 will wait for 3 seconds before putting its f0 port in prune state. If within 3 seconds , R1 does not receive any joint message from R3 , R1 will put its f0 int in prune state.

What if we do not have R3 on LAN rather just R1 and R2 and R2 sends a prune message to R1? Will R1 still wait for 3 seconds ?

Thanks and have a great weekend.

[Reza Sharifi · Accepted solution]

Hi Sarah,

The behavior would be the same. When R2 detects that there is no longer any directly connected hosts, it will send a prune message to R1, R1 will wait the interval between prune messages (in yours case is 3 seconds) and then the flow stops.

BTW, according to IETF, the default join/prune interval is 60 seconds.

[Join/Prune-Period] This is the interval between
sending Join/Prune messages. Default: 60 seconds

more info here:

http://www.ietf.org/rfc/rfc2362.txt

Have a great weekend

Reza