Multicast Issues

burbankmarc

Hey all, I'm having some problems with multicast.

My users use a web application to view real time stats and what not. You can see in the diagram at each facility there are 2 servers, a CCMS and CCMA server. The CCMS sends the stats to the CCMA through 225.0.0.1 and the users actually connect to the CCMA server through their respective multicast group. This all works fine on the local LAN.

So the issue is when they connect to the remote facility multicast doesn't work. Which normally wouldn't be a problem because the servers can use unicast if multicast isn't set up. But here's where it gets a little strange. The users try to connect via multicast to the remote server, that fails so it switches to unicast. While in unicast the client actively seeks a multicast connection since it's the preferred method. Every now and again the multicast WILL work and the clients switch to multicast, but the multicast packets stop coming after a few seconds.

I have PIM sparse-dense mode configured with a static RP. I'm sending all multicast traffic over the MPLS through a GRE tunnel. Any help would be greatly appreciated.

Thanks!

APA

RP is nailed at which device?

To me it sounds like the SPT to the RP is being pruned intermittently.......

Have you got outputs from all relevant devices for the following during working state and broken states?

- sh ip mroute
- sh ip mroute active
- sh ip route x.x.x.x (where x.x.x.x = the source of the Multicast traffic)
- sh ip rpf
- sh ip pim neighbor

What IOS are you running as well??

I remember playing around with Multicast over GRE tunnels quite some time ago.... this document was pretty handy.....

Multicast over a GRE Tunnel - Cisco Systems

burbankmarc

I fixed it. I believe it had to do with the ASA and the 3750's. I manually made DRs for the HSRP active routers. Traffic is passing and things are good to go.

Tip- Do not underestimate the importance of PIM's DRs.