Multicast across vlans

Answered Question
Feb 16th, 2010

I am was trying to configure multicast streaming on our campus network and was having issues getting the multicast to work when the sender and reciever were in different vlans.  Our core switches are 2-3550's set up with HSRP and SVI's for each vlan.  I have ip multicast-routing enabled and each SVI on each core switch has ip pim sparse-dense configured on it.  The sender and the reciever are both on the same 3560 switch which is trunked to one of the core 3550's.  If both the sender and recieve are on the same vlan the multicast works fine but once they are put on different vlans the stream will not work.  I was testing this using VLC player as the streaming server and the reciever was using VLC as well set up using UDP multicast to a 239.255.x.x address.

What am I missing to make this work.

Thanks in advance for your help.

Jeff

I have this problem too.
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Correct Answer by Reza Sharifi about 6 years 9 months ago

Hi Jeff,

On the sender side of the VLC, did you increase the TTL to 2?

Once you increase the TTL make sure to restart the session on the receiving site.

HTH

Reza

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Correct Answer
Reza Sharifi Tue, 02/16/2010 - 19:46

Hi Jeff,

On the sender side of the VLC, did you increase the TTL to 2?

Once you increase the TTL make sure to restart the session on the receiving site.

HTH

Reza

Kevin Dorrell Tue, 02/16/2010 - 19:54

Some suggestions for diagnostic information:

Could you post a show ip mroute please?

Also, are you using IGMP snooping on both VLANs?  If so check on the 3560 that that both VLANs have identified the link to the core as the mrouter port.  Also look at the ip igmp snooping groups.

Kevin Dorrell

Luxembourg

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