PIM Sparse Mode and SPT switchover

Hey guys,

I'm having difficulty understanding this, here is the basic topology -

R6-------R4 -----R5------SW2-------SW4

R5 is configured as the RP, SW4 has joined the multicast group 224.10.10.10.
I am pinging 224.10.10.10 from R6 and I am expecting to see *,G and S,G
entries on the RP (which I do).

However, on R1 and R2 I am seeing port *,G and S,G entries.
I have configured *ip pim spt-threshold infinity* on SW4 to prevent the SPT
switchover, cleared the mroutes and started a ping from R6 again - still I
get the same results.

R5:
Rack1R5#show ip mroute
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,
       V - RD & Vector, v - Vector
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 224.10.10.10), 00:07:18/00:03:08, RP 150.1.5.5, flags: S
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    FastEthernet0/0, Forward/Sparse, 00:07:18/00:03:08
    Serial0/1/0, Forward/Sparse, 00:05:55/00:02:31

(155.1.146.6, 224.10.10.10), 00:06:54/00:03:20, flags: T
  Incoming interface: Serial0/1/0, RPF nbr 155.1.45.4
  Outgoing interface list:
    FastEthernet0/0, Forward/Sparse, 00:06:54/00:03:08

(*, 224.0.1.40), 00:08:13/00:03:27, RP 150.1.5.5, flags: SJCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    FastEthernet0/0, Forward/Sparse, 00:08:07/00:03:19
    Serial0/1/0, Forward/Sparse, 00:06:57/00:03:27

Rack1R5#

SW2 Output:
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
       V - RD & Vector, v - Vector
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 224.10.10.10), 00:08:02/00:03:18, RP 150.1.5.5, flags: S
  Incoming interface: Vlan58, RPF nbr 155.1.58.5
  Outgoing interface list:
    Port-channel1, Forward/Sparse, 00:08:02/00:03:18

(155.1.146.6, 224.10.10.10), 00:07:38/00:03:22, flags: T
  Incoming interface: Vlan58, RPF nbr 155.1.58.5
  Outgoing interface list:
    Port-channel1, Forward/Sparse, 00:07:38/00:03:18

(*, 224.0.1.40), 00:08:52/00:03:19, RP 150.1.5.5, flags: SJCL
  Incoming interface: Vlan58, RPF nbr 155.1.58.5
  Outgoing interface list:
    Port-channel1, Forward/Sparse, 00:08:02/00:03:19

SW4 output:
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
       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

(*, 224.10.10.10), 00:10:37/stopped, RP 150.1.5.5, flags: SCL
  Incoming interface: Port-channel1, RPF nbr 155.1.108.8
  Outgoing interface list:
    Vlan10, Forward/Sparse, 00:10:37/00:02:41, H

(155.1.146.6, 224.10.10.10), 00:00:10/00:02:59, flags: LJT
  Incoming interface: Port-channel1, RPF nbr 155.1.108.8
  Outgoing interface list:
    Vlan10, Forward/Sparse, 00:00:10/00:02:49, H

(*, 224.0.1.40), 00:10:37/00:02:50, RP 150.1.5.5, flags: SPCL
  Incoming interface: Port-channel1, RPF nbr 155.1.108.8
  Outgoing interface list: Null

Rack1SW4#

SW4 config -
ip pim spt-threshold infinity

interface vl25
ip igmp join 224.10.10.10

Any suggestions?
Maybe I'm misunderstanding something here?

Thanks

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Received on Tue Jul 26 2011 - 21:35:36 ART