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

Attention: The Community will be in read-only mode on 12/14/2017 from 12:00 am pacific to 11:30 am.

During this time you will only be able to see content. Other interactions such as posting, replying to questions, or marking content as helpful will be disabled for few hours.

We apologize for the inconvenience while we perform important updates to the Community.

New Member

duplicate multicast on a bridge

Hi, I have a situation with a router connected to 2 switches on the same LAN that are bridged together. The BVI has pim dense-mode and there is a tunnel to another network. The problem is that all incoming multicast traffic from the LAN is sent twice over the tunnel (I presume from debugging that it is because the packets are coming in through both interfaces that are bridged together. The router is a 2811. Any insight on this would be great, thanks.

1 REPLY
Silver

Re: duplicate multicast on a bridge

Duplicate multicast packets are symptoms of several things:

- An Ethernet-level device (e.g. bridge) that doesn't understand multicast so reforwards it. This is easy to track to the right subnet using mtrace's packet statistics, but hard to track to the final device because it doesn't change the ethernet source address.

- Forwarding loops. This is often due to a misconfigured router

100
Views
0
Helpful
1
Replies
CreatePlease to create content