[c-nsp] Multicast Reporting......

[Phil Mayers]

On 09/05/2014 16:26, Scott Voll wrote:
> OK so we are moving from a Unicast to Multicast video stream and we have
> been reporting on how many people are watching the stream.  as we move this
> to a multicast stream how do I report on how many people are watching?
>
> Are there package apps that will do this?  the only thing I can think to do
> is run through every switch and see if it's receiving the stream and try to
> sparse out the numbers.
>
> There has to be a better way

Depends on the network topology and devices.

e.g. In our network, multicast receivers have cat6k as the last-hop 
egress router, and routed interfaces are SVIs. In this config, you can run:

sh ip igmp snooping statistics [int VlanX]

...which shows something like what you want:

Source/Group        Interface   Reporter     Uptime Last-Join Last-Leave
0.0.0.0/239.a.b.c   VlX:GiX/Y   192.0.2.28   4w0d   4w0d          -

The absolute furthest "up" (towards the source) you might gather ths 
info is the last-hop router(s) for all the receiver(s) as hops further 
upstream just don't see receiver activity, only aggregated joins.

Obviously layer2 devices downstream of the last-hop router will see it 
and may or may not give you this info.

A totally different approach is to have the receiver report back via 
RTCP or similar, but obviously that requires client-side software support.