multicast group traffic filtering

multicast group traffic filtering

[Jon Webb]

Hi everyone,
I am trying to think of a way to handle a multicast test network. We 
have a setup that may require having a multicast router in a network 
that contains other multicast activity. This extra router would only 
want to route multicast traffic (control and data) for a specific 
multicast group (our test group), ignoring all other multicast traffic 
not part of that group. I know that the matching code is able to match 
on a multicast packet type, but I need to match on a specific group. I 
looked around the docs, but have been unable to find any kind of --match 
type support for multicast group ID's or some sort of IGMP connection 
tracking/handling. Is there something I missed? Can this be done with 
existing tools? Or else, could this be easily constructed?

Thanks,
Jon

-------------
jon_webb@binary-one.com
jonwebb@soe.ucsc.edu
Computer Communications Research Group
University of California, Santa Cruz

Re: multicast group traffic filtering

[Henrik Nordstrom]

On Mon, 22 Dec 2003, Jon Webb wrote:

> not part of that group. I know that the matching code is able to match 
> on a multicast packet type, but I need to match on a specific group.

I thougt multicast groups was just IP addresses in the multicast class of
IP addresses... doesn't using the --destination match work?

But you really should be having this kinds of filters in the IGMP router
to not route memberships for other multicast groups. There is no good in
requesting multicast messages from your neighbors if you then decide to
immediately drop the same..

> or some sort of IGMP connection tracking/handling.

What would one connection track in multicast? Last time I looked there was 
no connections, just unspecified flows of traffic within each group.

Regards
Henrik