Re: Regarding Multicasting

Hi Raghav

I have couple of queries in Mulitcasting:-

>
> PIM-DM
>
> 1. If we have a route coming via Fast Ethernet as well as Serial Interface
> but it is preferred via Fast Ethernet due to low cost in OSPF. Now using
> PIM
> - DM while doing the RPF check we find that the route should come via
> Serial
> Interface, so we have 2 options there:-
>
> ----> Change the cost on Fast Ethernet link so that it prefers Serial
> interface *OR*
> ----> Configure a static mroute entry for that route pointing to the
> next hop which should be serial interface.
>
> Now lets say I use the static route option. when I configure my router
> everything works RPF check succeeds etc etc. What my query is should i see
> that route in the IGP Routing table to come via Serial Interface or Fast
> Ethernet interface coz earlier it was coming via Fast Ethernet ? Also
> whatever is the answer why??

*mroute does not affect the IGP routing table. It is only used decide the
RPF information.*
So you wont see any changes to your IGP routing table.

>
> PIM- SM
>
> 1. We are using static RP configuration on all the routers . now lets say
> if
> on one of my routers I have 2 Fast ethernet interfaces i.e Fa0/0, Fa0/1.
> Now
> only Fa0/0 is configured for PIM- SM. My questions are:-
>
> -------> If I configure IGMP Join group 224.1.1.1 on this router , I
> will also have to configure the configuration for static RP i.e ip pim
> rp-address x.x.x.x 1 along with the access-list permitting that multicast
> IP.
> Because what i know is that when we use static RP we have to configure it
> on
> all the Routers coz otherwise the Routers will not know who the RP is . So
> even If we configure the IGMP join-group command on this router do we also
> need the static RP config. Please correct me If I am wrong??

*Having configured pim sparse mode. The PIM router needs to send join
messages towards
the RP. Without this, how will it receive multicast traffic, since by
definition sparse mode sends only
multicast traffic to routers that request it.*

>
>
> -------> Second question is since PIm- SM is not enable on Fa0/1 , can
> I configure IGMP-JOIN group command on this interface. Also something to
> note here is there is no ip address. Can we do this???
> I am kinda confused in this one.

*
Now since the router is already receiving multicast traffic (int f0/0 in
sparse-mode and RP configured)
You can enable ip igmp join-group on fa0/1 so it joins the multicast group.
However ,an ip address
is also necessary without which it will be not able to respond to IGMP
queries or send IGMP membership
reports and hence cannot join the multicast group.*

Lejoe

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Received on Tue Jun 02 2009 - 17:44:03 ART