Let's see how well IGMP and PIM play together when Wired
Brain Coffee starts sending traffic.
Okay,
I promised I wouldn't go far outside the scope of IGMP or MLD in this course.
I will show a few short flow demonstrations so we can
watch multicast function in the network.
Otherwise, on one will believe me that the protocol is actually working.
We've already verified that R1,
the last hop router in front of the Globomantics clients,
is aware that it has interested receivers on groups 239.1 .1 .1,
and 239.2 .2 .2.
Assuming PIM is properly configured,
the server should be able to just start sending multicast.
Cisco iOS supports ICMP ping to test multicast in a simple way,
so I'll start a long ping test from the Wired Brain Coffee server.
We see responses from 10.1 .4 .4, which is good.
Let's jump over to R1 to check its counters.
I'll look at the multicast routing state entry counters a few times in
succession just to show increasing packet counters.
The highlighted boxes are continuously increasing,
indicating a healthy flow of traffic.
In future flow videos,
we'll explore cutting off this traffic to see how it behaves.
Looks like everything is working for now.
I want to summarize what we've covered in this module before continuing.
IGMP and MLD, the primary focus of this course,
govern multicast group memberships between N hosts and multicast routers.
PIM is a multicast routing protocol used between routers to
move multicast across IP routed networks.
RPF is a key concept in PIM tree construction and multicast loop prevention, which uses IP routing back towards a multicast source.