[c-nsp] multicast on transit LAN

Marco Regini marco.regini at ascotlc.it
Tue Feb 16 11:45:01 EST 2010

Hi Phil,
all my cisco are routing the multicast, the problem is that the l3 link between them are not point-to-point.

I tried to enable rgmp,cgmp ... but seems they assumes the apparatus being a router or a switch ( if the cisco has a svi on the vlan 100 it is a router, if not is a switch). I'am not sure if proxing the IGMP will works, because IGMP snooping probably has the same limitation, but I want to tray; do you know how to enable it?

This is a pseudo configuration of apparatus, what lines I need to proxy the IGMP arriving to the access interface Fa0/30?

interface Vlan 100
  description L3 DAESY-CHAIN-NUMBER-100
  ip address
  ip pim sparse-dense-mode
interface range Gi 0/1 - 4
 description L2 DAESY-CHAIN-NUMBER-100
 switchport mode trunk
 switchport trunk allowed vlan 100

On the access apparatus there are the Customers interface.

interface Fa0/30
 description L2 Customer Smith
 switchport access vlan 30
interface Vlan 30
 description L3 Customer Smith
 ip address

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Phil Mayers
Sent: martedì 16 febbraio 2010 16:37
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] multicast on transit LAN

On 02/16/2010 11:29 AM, Marco Regini wrote:
> My last chance is to proxy the IGMP, let me explain:
> Receiver --Vlan7-- Fa0/7.Catalyst3560.Gi0/1---Vlan100-Gi0/1.Catalyst3750

So the 3560 and 3750 are routing the multicast?

In that case you probably need PIM snooping on the layer2 equipment 
between them. If you don't have that, then yes - IGMP proxy is an option.
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