From: Darren Johnson (dazza_johnson@yahoo.co.uk)
Date: Tue Jan 08 2008 - 17:19:13 ARST
Hi group. I've been doing some testing on this, and have the following
conclusions.
R1 connects to R2, R2 connects to R3. R2 has a loopback interface with an
IGMP join to multicast group 225.1.2.3 and the R3 interface which connects
to R2 has the same IGMP join.
To successfully receive ping responses (to 225.1.2.3) generated on R1 from
R2 and R3, the following is required:
R1
Nothing. No pim, not even multicast-routing is needed. The router is treated
as a host with regards to multicast. Even without multicast enabled, the
router can send multicast traffic (not receive though).
R2
Need multicast-routing enabled, and PIM on the interface that connects to
the source. The loopback needs only the igmp-join (no pim needs configuring
on this interface).
R3
Needs multicast-routing enabled. PIM needs enabling on the interface that
connects to R2 (at both ends of the link). Igmp join needs configuring on
the R3 end of the link.
Interestingly, I didn't think PIM would need enabling on the R3 end of the
link - as long as IGMP join was configured. The idea being that R3 could
still send the IGMP join and as long as the R2 end of the link had PIM
enabled, it would forward the multicast - however this didn't work :-( Still
needed PIM.....
In summary, when using loopbacks as multicast receivers you do not need PIM
enabled. For multicast sources, you do not need any multicast commands
configured. When using physical interfaces, as well as the igmp-join you
need PIM enabled.
Hope this makes sense and helps.
Dazzler
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
shiran guez
Sent: 11 December 2007 11:54
To: Sridhar Vaidyanathan
Cc: Cisco certification
Subject: Re: Multicast on interface on which hosts is connected
Host Communicate to Routers via IGMP and routers communicate to each other
via PIM.
PIM is only to set the Multicast Routers Path for sending Multicast traffic.
it is like you do not use Routing Protocol to communicate with your directly
attached router, you use arp or ipv6 icmp nd.
On Dec 11, 2007 10:17 AM, Sridhar Vaidyanathan <vsridhar83@gmail.com> wrote:
> Dear All,
>
> Is it required for enabling PIM on a fastethernet interface which is
> connected to Multicast receivers? Assuming that the router is a Stub
> Router
> and has one serial connection through which the router receives multicast
> feeds and PIM is enabled on the serial interface.
>
> Regards,
> Sridhar.
>
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-- Shiran Guez MCSE CCNP NCE1 http://cciep3.blogspot.com http://www.linkedin.com/in/cciep3
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