Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Multicast routing between sites


I run a multicast setup on site A

The multicast is provided by a IPTV provider.

Uplink for the service is at site A

The Cisco 3750 on site A is my RP.

Now I have a new site, site B, where I also need this multicast.

Also run a 3750 here.

What I have done is created a link net between the sites.

Set PIM Sparse mode on the interfaces linking them.

Enabled ip multicast-routing distributed on site B also.

Set up a VLAN on site B for distributing the multicast.

Enabled PIM sparse mode on this VLAN.

But the multicast will not work.

Am I forgetting something here?

New Member

Multicast routing between sites

ok lets start  1) do you have autorp listner enabled on the sw

                     2) do show ip pim rp maping

for multucast to work in space mode you must have conection to the RP from source and reciver

do this then lets know whats up

New Member

Multicast routing between sites

Thank you

I tried to enable autorp listner, but nothing showed up in the ip pim rp maping table.

In order to make this work, do I have to make the Cisco 3750 on site B a RP also?

New Member

Re: Multicast routing between sites

How did you link two sites. Are these remote location. Im interested in something like this

Sent from Cisco Technical Support iPhone App

New Member

Multicast routing between sites

The two sites are remote yes, linked via a leased 200Mbps L2 connection.

Multicast routing between sites

if the new site connected over L2 you do need to enable mcast on the L2 link

it is requried on the L3 interfaces only

make sure you have the igmp snooping enabled in your switches and also the L3 interfaces SVIs or physical

Multicast routing between sites


Enabling PIM will automatically enable IGMP.



Re: Multicast routing between sites


Looks like the problem you have is that the igmp join messages from one switch are not reaching the RP on the other switch.

The below link should help you understand the  problem between 2 cisco switches connected via a L2 link which is your scenario

Mrouter Port

The mrouter port is simply the port from the switch point of view that connects to a multicast router. The presence of at least one mrouter port is absolutely essential for the IGMP snooping operation to work across switches. The Understand the Problem and Its Solutions section of this document discusses this requirement in more detail.



New Member

Multicast routing between sites

Thank you all for helping.

Got it working now.

I had forgot to issue the command:

ip pim rp-address xx.xx.xx.xx

On site B.

Multicast routing between sites

Hey perpaal,

Glad to know that you got it working and thanks for letting us know the problem and solution as well. We all learn from each other