Client1 is configured to join multicast destined for group 226.0.0.1 and sent from Server1
Instead of PIM-Dense (flood and prune) we use PIM-Sparse to build the forwarding path from the server to the client
PIM-Sparse is enabled on R1, R2, R3 and R4 routers
We use RIP for unicast routing and multicast ping from the source for test purpose
At R1 we check that Client1 is registered to the group
The interface facing Client1 is configured for PIM-Sparse
The details…
All interfaces are configured for PIM-Sparse
We check PIM neighborship established between R2 and R1
Let’s enable multicast routing and check the mroute table
After a while the mroute table get populated by group 226.0.0.1 information
The RP Rendez-vous Point is set to local
Let’s send trafic from the server
At R4,
The router receives trafic from the source but fails routing it
The mroute table is empty of 226.0.0.1 group information
We activate PIM on the fa0/0 interface (to enable multicast packets processing) and run a debug ip mfib pak
A debug on R1 shows the packet from the server fails the acceptance check
Is it due to sparse mode? Or in general?
We put the interface into dense mode
the debug shows
The flow is now accepted but fails because of no forwarding interface
We configure back the interface into sparse mode
In addition, we configure R4 to be a RP (static)
Now the packet is accepted for forwarding
But because of no forwarding interface the packets are dropped
We check also that R4 initiates the register process with the RP (which is R4 in our case)
At R4,
The mroute table is populated by (S,G) entry but it is pruned beaucause of the outgoing interface list is empty
Let’s configure the RP on the other routers
At R1 as soon as we configure the RP address
We check that R1 build a join message for 226.0.0.1 and put it in R2 queue
At R2,
The router has no idea about RP and consequently invalidates the join received from R1
We configure the RP information on the remaining routers R2 and R3
Now the server is getting response from the client
At R3 the mroute table shows
The RP information is correct and the RPF is set to R4 on the fa1/0 interface
At R2 we add a new link to R4
The ping from the server stop working
Any idea?