Re: IP layer and layer 2 IGMP Snooping

On Jun 11, 2:38 pm, vicky <vikrant.pan...@xxxxxxxxx> wrote:

My new query is related to registration in a mulicasting group so for
i m taking a case

For exp

 let 's say there are 10 pc's (hosts)
 one multicasting router
 a layer 2 switch (IGMP Snooping capable)  is in between the hosts and router
 out of 10 hosts 5 will register in a multicasting group and another will register in another multicasting group
 but there each registration time is not same (one sent membership request at one time another send its group

    registration in an another time)

 Now what the data to be multicast (by router) is at time (let at 2 pm)

so registration for different multicast group is sent by hosts is some
before

So my question is if by one host the registration is sent some hours
before as well as by anther one is few minutes before the fix time of
multicast data is flow by router , so how the layer 2 switch manages
there (hosts) table  ?

The IGMP snooping switch must send "join" messages to the router if
there is at least one host connected to that switch wants to join the
multicast group. So as soon as that first host joins, the multicasts
reach the switch.

But the snooping switch also keeps track of each individual host that
indicates it wants to join the group, and only forwards the multicast
packets on THOSE ports. And it also keeps track of the leave messages,
to stop forwarding to particular switch ports.

So, no problem if hosts join late or leave early.

Read

http://www.ietf.org/rfc/rfc4541.txt?number=4541

Bert
.

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