Transition from multicast dense to sparse mode

[jsluzewski]

A multisite network is currently supporting muticast using PIM dense mode, which is enabled on router/switch LAN and WAN interfaces across all locations. I am about to introduce Nexus switches to the main LAN. How can I make dense and sparse mode coexist to ensure flow of muticast traffic between devices supporting and dense and sparse mode? Eventually, I want to transition  to the sparse mode; however, it has to be done gradually, even within a single site.

The leacy equipment includes Cat 3750 and  4500s.

Jarek

[John Blakley]

Jarek,

I would probably recommend that you set your interfaces to "ip pim sparse-dense" in order to be able to support both. This mode on the interface will support groups that are in sparse mode (those that have an RP and are aware) and those groups that are in dense mode. After you completely transition over to sparse only, then you can change your interfaces to "ip pim sparse" and then you'll only support sparse mode.

HTH,

John

[jsluzewski]

Sparse-dense mode is not supported by the Nexus. Ultimately I will be facing a situation where two routers; one running sparse and the other  dense mode, will be requiured to pass multicast for the same group between each other ( as in the scenario when the routers are at the opposite ends of a WAN link). I am not sure how it can be achieved.