[nsp] Multicasting

Tim Stevenson tstevens at cisco.com
Thu Feb 12 11:37:32 EST 2004

Not really. All 6500 sups as well as the 3550 support IGMP snooping in hardware. It is enabled by default. CGMP is not required (nor are the "switch" side functions even implemented), unless you have legacy boxes that don't do IGMP snooping, in which case you need the CGMP "router" side functions enabled, ie, "ip cgmp" under your VLAN/L3 interface(s).

I see you are planning to do disk imaging, this is presumably with "norton ghost" or a similiar app. Please do be careful of issues with multicast traffic with TTL=1 hitting your 6500s or other downstream routers, this will cause high CPU. Latest versions of Ghost have a knob to tweak the TTL of the imaging data packets, I recommend finding & tweaking that knob.


At 05:22 AM 2/12/2004, cisco-nsp-request at puck.nether.net proclaimed:
>Date: Thu, 12 Feb 2004 11:29:05 +0100
>From: BERKANE Mourad <mourad.berkane.prestataire at sfrcegetelsi.fr>
>Subject: RE: [nsp] Multicasting
>To: "'Rieman, Jeff'" <j-rieman at onu.edu>
>Cc: cisco-nsp at puck.nether.net
>Message-ID: <AD1FDC089AD7D611A6340002A5438FDD08D32DFF at sisyphe>
>Content-Type: text/plain;     charset="iso-8859-1"
>You will need to enabled CGMP, if not multicast = broadcast :-)
>-----Message d'origine-----
>De: Rieman, Jeff [mailto:j-rieman at onu.edu]
>Date: mercredi 11 février 2004 19:43
>À: cisco-nsp at puck.nether.net
>Objet: [nsp] Multicasting
>Hi, we have a cat6509 at the core of our network and a boatload of 3550s
>on the spokes.  We are working on some disk imaging and need to enable
>multicasting acrossed the network.  Looks like I need to enable igmp on
>the 6509?  Anything need to be done on the 3550s?  Sorry, pretty much a
>cisco novice here.  Anything I need to look out for?
>Thanks in advance!
>cisco-nsp mailing list  cisco-nsp at puck.nether.net
>archive at http://puck.nether.net/pipermail/cisco-nsp/

Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Catalyst 6500
Cisco Systems, http://www.cisco.com
IP Phone: 408-526-6759
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