From: gladston@br.ibm.com
Date: Tue Aug 16 2005 - 15:23:24 GMT-3
Hi,
Cisco doc (http://www.cisco.com/en/US/tech/tk828/technologies_white_paper09186a00800d6b61.shtml)
and Williamson (page 460) has examples where the C-RP is located on spoke.
But hands on shows it does not work when a spoke is connected to a source and the other spoke is connected to a receiver.
The only way to get multicast flow from a spoke to another spoke is changing the C-RP to the Hub (and configuring ip pim nbma-mode, but this is not the problem)
Do you have a different experience?
Test:
This works fine. C-RP on Hub:
R5 is the hub.
R2/R3 are connected on R5's serial 0/0.
Rack2R5#sh ip mrou 239.55.1.1
(*, 239.55.1.1), 00:11:18/stopped, RP 148.5.5.1, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Serial0/0, 148.5.235.2, Forward/Sparse, 00:09:29/00:02:58
(148.5.38.8, 239.55.1.1), 00:11:18/00:03:25, flags: T
Incoming interface: Serial0/0, RPF nbr 148.5.235.3 <----source on s0/0
Outgoing interface list:
Serial0/0, 148.5.235.2, Forward/Sparse, 00:02:32/00:00:58 <--receiver on s0/0
This does not work. C-RP on spoke R3
R2 sends join toward the RP, but debug on R5 does not shows this join coming in:
Rack2R5#debug ip pim
Rack2R2(config)#int lo 0
Rack2R2(config-if)#ip ig join-group 239.33.1.1
Rack2R5#sh ip mrou 239.33.1.1
Group 239.33.1.1 not found
R2 knows the RP
Aug 16 15:10:58: PIM(0): Building Triggered Join/Prune message for 239.33.1.1
Rack2R2(config-if)#do sh ip mrou 239.33.1.1
(*, 239.33.1.1), 00:53:40/00:02:36, RP 148.5.3.1, flags: SJCL
Incoming interface: Serial0/0.235, RPF nbr 148.5.235.3
Outgoing interface list:
Loopback0, Forward/Dense, 00:00:23/00:00:00
So, have you ever configured a situation similar as the example on Cisco and Williamson, and get multicast packets flow from spoke to spoke?
Researching on groupstudy I found this threat about multicast over FR:
http://www.groupstudy.com/archives/ccielab/200405/msg00404.html
It seems Bob also only got spoke to spoke moving RP to hub.
It seems something on the spoke, when comparing debug from join a group on Hub and a group on remote spoke:
Rack2R2(config-if)# ip igmp join-group 239.55.1.1
Rack2R2(config-if)#
Aug 16 15:15:23: PIM(0): Building Triggered Join/Prune message for 239.55.1.1
Aug 16 15:15:23: PIM(0): Insert (*,239.55.1.1) join in nbr 148.5.235.5's queue
Aug 16 15:15:23: PIM(0): Insert (148.5.38.8,239.55.1.1) sgr prune in nbr 148.5.235.5's queue
Aug 16 15:15:23: PIM(0): Building Join/Prune packet for nbr 148.5.235.5
Aug 16 15:15:23: PIM(0): Adding v2 (148.5.5.1/32, 239.55.1.1), WC-bit, RPT-bit, S-bit Join
Aug 16 15:15:23: PIM(0): Adding v2 (148.5.38.8/32, 239.55.1.1), RPT-bit, S-bit Prune
Aug 16 15:15:23: PIM(0): Send v2 join/prune to 148.5.235.5 (Serial0/0.235)
Rack2R2(config-if)# ip igmp join-group 239.33.1.1
Rack2R2(config-if)#
Aug 16 15:17:38: PIM(0): Building Triggered Join/Prune message for 239.33.1.1
It stops here...does not send the join/prune.
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