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PIM sparse or bi-directional


I have a large network running multicast. There are approximatly 50 sites which source multicast traffic. Each of the sites has 2 devices (main and standby) these both communicate permenantly to multiple receivers on the same group. This is a many to many topology. I also have point to multipoint traffic from the on-line sourcing device to multiple receivers spread over different LAN's. I have used PIM sparse-dense mode with an RV point. Recently we have had the odd bit of traffic failing to get through the network. Sometimes one multicast group fails, sometimes the other. Should we be using bi-directional PIM. Its not configured and after reading up it seems we would have to have it, yet its not currently configured and 99% of the network gives us no problems. Have we reached a point where sparse mode isn't scaling well and we need to consider bi-dir? It seems PIM prunes back the traffic even through we have regular IGMPv2 requests coming into the routers from the clients. "sh ip igmp gr". Sometimes the problem can be fixed by forcing the traffic to be received near the RV point on a spare client PC. Looks like it gives the network a kick and all comes back OK. Even if we re-start the applications on the normal clients we still dont get traffic back. Any suggestions welcome.

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Re: PIM sparse or bi-directional

Hello Nathan, I tried to email you directly but perhaps I didn't guess your email correctly. I have a buddy of mine that can answer your question directly, but he doesn't subscribe to the forum. In fact he just left Cisco to start a multicast management software company of his own! You can email him directly at


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