All things related to multicast

[Dave McGaugh <>]

So we have a recent issue we have uncovered with Foundry Big Irons 
(running Layer 2 only software) in our lab. Currently it appears that 
the IGMP snooping capabilities of these devices top out at 1024 
multicast groups. This by itself does not immediately seem to be a 
problem however, the IGMP membership queries themselves generated by 
the attached router count against this number and identical groups on 
separate VLANs are summed together. So for example, if a single box has 
1024 VLANs provisioned on it, the IGMP membership queries alone with 
exhaust your IGMP snooping capacity. A case is open with Foundry to 
find out if there is another way to address this.

-Dave

On Sep 8, 2004, at 8:55 AM, Alan Crosswell wrote:

> Hello,
>
> In an effort to improve the Internet2 Multicast Working Group's 
> hands-on tutorials I write to solicit feedback on your experiences 
> with support for multicast in the LAN.  Topics of interest include 
> experiences pro and con with IGMP v2/v3, MLD v2 snooping; Practical 
> results and switch vendor compliance with 
> http://www.ietf.org/internet-drafts/draft-ietf-magma-snoop-11.txt;  
> Experience of medium and large-scale campus multicast deployments both 
> in terms of number of "channels" and bandwidth; and so on.
>
> I look forward to reading your war stories:-)
>
> /a