Subject: RE: [magma] Questions with IGMP Snooping

From: "Bryan McLaughlin \(brmclaug\)" <[email-masked]>
Date: Fri, 17 Dec 2004 16:31:10 +0100

> [BMc>] a snooping switch will look at IGMP packets only. 
>   

What Bryan means is that the Switch CPU should look at IGMP packets
only; to do this, it is not enough to look at the Ethernet MAC address
in IGMP v1 / v2, but also the IP header.
Beau describes why you really don't want to do IP header inspection in
the CPU, but lower down in the switching engine. This is not a problem
for v3.

The real trouble here, of course, is the still paltry deployment of IGMP
v3. 

BMC> Marshall you are correct that IGMP snooping needs to be done in
hardware. To be clear, as the above could confuse the neophyte. AFAIK
all current/recent switches use ASICs to identify IGMP packets in
hardware. So IGMP snooping for V1/2 is working today. 

Cheers

Bryan

_______________________________________________
magma mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/magma

---

From: Alan Crosswell <[email-masked]>
Date: Fri, 17 Dec 2004 11:05:23 -0500

See http://www.columbia.edu/~alan/igmp for some recent work I've been doing 
looking at a couple of switches' IGMP snooping capabilities.  Feedback on my 
methods, things I've left out, etc. would be appreciated.
/a