Multicasting with GNS3 and Virtualbox

There were many times during my CCIE Lab preparation that I wanted to have an actual Multicast server to lab up multicasting but I had always been left with ping to test and troubleshoot multicasting. There were 2 problems to it. The first is that it is a dull and boring multicast source which can be easily switched from one router to the other which if you think, is not a good thing because multicast sources are servers which remain steady in one place. When you shift your multicast source, clarity is lost about where the source is and where the destinations could be. The second is that a receiver is simulated using an IGMP join group which again is a simulation and not an actual receiver. It could be useful in testing but not perfect. With the release of GNS3 with Virtualbox, we can simulate the whole Internet over it, if we wished (and obviously if we had resources for it). By using GNS3 and Virtualbox, we are going to send Multicast Traffic from multicast source to any multicast receiver who intends to listen to it. In this blog, we will see how to send and receive actual multicast traffic through a routed network. I could have just put a multicast source and receiver on the same router to show that multicasting works on GNS3 and Virtualbox but it wouldn’t help anyone of us gaining knowledge. So I decided to run multicasting on a 6 Router topology so that we could run multicast routing, pim sparse mode and maybe look into some issues which multicasting can give us. Continue reading