[c-nsp] multicast on transit LAN

Marco Regini marco.regini at ascotlc.it
Tue Feb 16 11:21:02 EST 2010

Hi Jon,
MVR is a very interesting feauture, thanks. I need some time to reflect, may be I'am not going to use it  this time but knowing i can do multicast in this way is important.

One question: how I use MVR with PIM?

On my 3570 ( my distribution router) I configure a svi 101

int Vlan 101
 description L3 FOR MVR MULTICAST
 ip address
 ip pim sparse-dense-mode

On my Catalyst 3560 ( my access apparatus) I do not create a svi 101 but simply put mvr on the access interface:

interface Fa0/30
 description L2 Customer Smith
 switchport access vlan 30
 mvr type receiver
 mvr vlan 101 group
interface Vlan 30
 description L3 Customer Smith
 ip address

-----Original Message-----
From: Bøvre Jon Harald [mailto:Jon.Harald.Bovre at hafslund.no] 
Sent: martedì 16 febbraio 2010 13:47
To: Marco Regini; cisco-nsp at puck.nether.net
Subject: SV: multicast on transit LAN

Might not solve your problem but have a look at a MVR vlan.



-----Opprinnelig melding-----
Fra: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] På vegne av Marco Regini
Sendt: 16. februar 2010 12:29
Til: cisco-nsp at puck.nether.net
Emne: [c-nsp] multicast on transit LAN


I 'am in a serious problem with multicast because my distribution ( Cisco Catalyst 3750) and access apparatus ( Cisco Catalyst 3560)  see each over via a common

network ( build on the common vlan 100).  Physically they are in daisy-chain with the gigabit interface, the gigabit are in trunk, all the L3 interface are SVI.


The problem is to limit the multicast traffic on this vlan because at L2 it is like a broadcast. Have you any suggestions?



I read documentation about CGMP,RGMP but on the notes there is written that this stuff works only  when multicast routers are connected via a
L2 switch, and regarding the vlan 100 my cisco are both router ( there is a svi ) and switch.


Another idea is to use IGMP snooping but my multicast receivers/sources are not in this vlan: so no IGMP traffic pass in this vlan.

My last chance is to proxy the IGMP, let me explain:


Receiver --Vlan7-- Fa0/7.Catalyst3560.Gi0/1---Vlan100-Gi0/1.Catalyst3750


If a configure the Catalyst3560 to proxy the igmp join/leave to upstream Catalyst3750 perhaps I give a chance to IGMP snooping to start working on Vlan100.


  Marco Regini


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