RE: PIM Sparse Mode and SPT switchover

Shane,

No one here can give you a better answer than the router itself.

What was the result of running debug ip pim on R5?

I'm willing to be in plain English (ok, ciscoese) the RP will let you know the before and after condition.

(Hint: how many paths do you have in this network for multicast traffic to flow down)

-Joe

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Shane K
Sent: Tuesday, July 26, 2011 4:36 PM
To: Cisco certification
Subject: 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 Wed Jul 27 2011 - 01:59:02 ART