Does Emulab support IP Multicast?
In short, yes, the local nodes in Emulab (but not all remote Netbed nodes) support IP Multicast on the experimental network. In order to use it, you must have a kernel that supports it, and if you want multicast routing, you’ll need to enable mrouted. (You can do it manually, or automatically via program objects or startup commands, but the rtproto commands will not do it.) When using multicast, there are a few issues you need to be aware of. The first is the fact that multicast traffic will often find the control network, rather than the experimental network, which you don’t want. See this section of the tutorial for information about the control net. There are two ways to work around the control net. The first is to set a route for all multicast addresses (224.0.0.0/4) to go out the experimental interface of your node. The second is to have your program use the IP_MULTICAST_IF sockopt to bind to a particular interface. You should also stay away from multicast addresses that have spec
