Subject: Proxy-IGMP ?

From: "Heiko W. Rupp" <[email-masked]>
Date: Wed, 8 Oct 1997 11:58:50 +0200

Hello,

I am not clear on this. I heard that there is such thing as proxy igmp
in order to support dial-in clients without the need for tunnels.
What is that exactly? What is needed and what benefits do i get?

Thanks
  Heiko

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From: "David W. Hankins" <[email-masked]>
Date: Thu, 9 Oct 1997 06:47:44 -0400 (EDT)

Traffic from Heiko W. Rupp:
> What is that exactly?

Well, IGMP is used for hosts to announce their group membership on a local
segment.  IGMP is proxied when one of those hosts receives IGMP group
membership advertisements, queries for updates on advertisements, and then
announces membership of said group(s) on a different segment.

The application would be for the "client" segments (the ones with hosts
being proxied) to be dialup serial interfaces, and the up-stream segment
(the segment proxied to) is the terminal server's ethernet.

> What is needed and what benefits do i get?

The software on your terminal server must support it, and then you must
provide your terminal server(s) with native multicast (a local mrouted box
on the segment, perhaps a Cisco or some other router which supports native
multicasting).

So far, Ascend and Cisco are the only ones I know of who does so; Cisco in
a different way, but same ends.  USR and Livingston have voiced their
intent to develop multicast, but I haven't been in the right circles to
hear anything about this for a few months.

The benefit is optimal multicasting to your dialup clients as opposed to
tunneling multicast to each individual client; one tunnel per client would
mean multiplying multicast traffic (worst case is all clients have joined
the same group) by the number of dialup clients you have online using
multicast.

-- 
David Hankins,             "If you don't do it right the first time,
Mercenary				    you'll just have to do it again."
							-- J.T. Hankins

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From: Dino Farinacci <[email-masked]>
Date: Thu, 9 Oct 1997 08:52:15 -0700 (PDT)

>> on the segment, perhaps a Cisco or some other router which supports native

    We do support IGMP proxy, see ftp://ftpeng.cisco.com/ipmulticast
    /stub_multicast.txt.

Dino