Multicast-PIM Sparse Mode

Instead of flooding multicast traffic to all potential receivers, PIM SM builds explicit multicast distribution trees from the receivers to the sources. To build an explicit tree to the source, receivers and sources should have a way to dynamically discover each other. This is facilitated by the use of Rendezvous Points


R1#
ip pim rp-address 4.4.4.4
!
interface FastEthernet0/0
 ip address 12.1.1.1 255.255.255.0
 ip pim sparse-mode
 duplex auto
 speed auto
end
!
interface FastEthernet0/1
 ip address 13.1.1.1 255.255.255.0
 ip pim sparse-mode
 duplex auto
 speed auto
end
R7#
!
interface FastEthernet0/0
 ip address 47.1.1.7 255.255.255.0
 ip pim sparse-mode
 ip igmp join-group 224.4.4.4
 duplex auto
 speed auto
end

%PIM-6-INVALID_RP_JOIN: Received (*, 224.0.1.40) Join from 23.1.1.2 for invalid RP 4.4.4.4
This error: a downstream PIM router sent a join message for the shared tree, which this router does not want to accept. This behavior indicates that this router allows only downstream routers join to a specific RP.

Change the rp address to 2.2.2.2 on all routers
#ip pim rp-address 2.2.2.2 





R4#show ip mroute 224.4.4.4
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 224.4.4.4), 00:17:16/stopped, RP 2.2.2.2, flags: SJC
  Incoming interface: FastEthernet0/0, RPF nbr 34.1.1.3
  Outgoing interface list:
    FastEthernet0/1, Forward/Sparse, 00:17:08/00:03:05

(1.1.1.1, 224.4.4.4), 00:00:04/00:02:55, flags: JT
  Incoming interface: FastEthernet0/0, RPF nbr 34.1.1.3
  Outgoing interface list:
    FastEthernet0/1, Forward/Sparse, 00:00:04/00:02:55