Lab 146 - PIM RPF Failure 2

Prerequisites: CCNP level skills.

Note!
All routers are running EIGRP protocol as well as multicast routing.

Topology

Pic. 1 - Topology Diagram.

Icons designed by: Andrzej Szoblik - http://www.newo.pl

Task 1
All routers have PIM Dense enabled on all their interfaces except for subnet (use R6's Et0/0). 10.1.51.0/24. The multicast clients on subnet 10.1.56.0/24 join 224.6.6.6 group.  Ensure that multicast clients can receive feed from 10.1.234.0/24 (R4).

Solution

Task 1

All routers have PIM Dense enabled on all their interfaces except for subnet 10.1.51.0/24. The multicast clients on subnet 10.1.56.0/24 will join 224.6.6.6 group (use R6's Et0/0). Ensure that multicast clients can receive feed from 10.1.234.0/24 (R4).

R6 Configuration:

!

interface Ethernet0/0
 ip address 10.1.56.6 255.255.255.0
 ip pim dense-mode
 ip igmp join-group 224.6.6.6

!

Verification:

Pic. 2 - Feed from R4 towards 224.6.6.6.

The feed does not reach the subnet 10.1.56.0/24. The reason is the Reverse Path Forwarding check failure according to IGP routing between R1 and R5. Like in the previous lab, where reaching RP is a subject to RPF check, here R1 picks the path through 10.1.51.0/24 to reach 10.1.56.0/24. These interfaces are not PIM enabled. 

Pic. 3 - R1's Routing Table.

The RPF check fails since the multicast traffic arrives on R5's Et0/1 interface instead of Se1/0.

Pic. 4 - R5's RPF Check Failure.

Pic. 5 - R5's IOL List.

In order to correct the problem, static mroute must be configured on R5.

R5 Configuration:

!

ip mroute 10.1.234.0 255.255.255.0 10.1.15.1

!

Pic. 6 - Multicast Feed Works.

Note!

Cisco's PIM based multicast traffic as well as the reachability towards RP (Sparse-Mode), are the subject to RPF check.