Multicast Graft and Prune Override

Hi fellas,

I was reading my Multicast theory and i have few doubts with the Dense
mode.

1)There is a Graft Ack message sent by the client to rejoin a particular
group , ( becasue already he is a member and then pruned and then again
joining ) , . At this point the First hop router should send just a Graft
Ack message to rejoin the group. If there is Graft concept. Why there is
the concept of Flooding n Pruning for every 3 minutes??

Because Graft Ack just solves the purpose of joining again instead of
waiting for 3 minutes for the FHR to send the feed again.
Can some explain me the use of Graft message and Graft Ack in Multicast

2)Regarding Prune Override .. If there are more than two routers say R1 and
R2 in a LAN domain. R3 is used as as the FHR towards the RP Now if a host
connected to R1 is sending a IGMP Leave message and now R1 sends a Group
specific query and if there is no host which replies to this query, now
then R1 will send a PIM prune message to 224.0.0.2 and now R2 receives it
and now it see that there is a host which is actively participating in that
group and it sends a Prune override to R3 and now R3 still sends traffic on
the link.

Correct me if i am wrong in the above statement. Can some one explain my
understanding is correct or not.

R3------------------| Sw1 |---------------R1--------Host 1
                          |
                          |
                          |
                         R2
                          |
                          |
                          |
                      Host 2
This is my scenario

With Warmest Regards,

CCIE KID
CCIE#29992 (Security)

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Received on Mon Nov 21 2011 - 16:51:50 ART