07-16-2010 12:44 AM
Hi All.
I have a customer who has there own private SRP ring using IS-IS as the IGP and TDP for the MPLS protocol.
Every now and then the IS-IS loses its adjacencys with the some of the routers on the ring. This also happens with TDP. Log messages for IS-IS below:
Jul 13 12:17:47.725 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6736 (SRP1/1) Down, hold time expired
Jul 13 12:17:48.725 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6736 (SRP1/1) Up, new adjacency
Jul 14 01:11:33.412 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6741 (SRP1/1) Down, neighbor forgot us
Jul 14 01:11:34.412 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6741 (SRP1/1) Up, new adjacency
Jul 14 08:16:52.117 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6750 (SRP1/1) Down, hold time expired
Jul 14 08:16:53.117 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6750 (SRP1/1) Up, new adjacency
Jul 14 16:07:11.178 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6747 (SRP1/1) Down, hold time expired
Jul 14 16:07:12.178 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6747 (SRP1/1) Up, new adjacency
Jul 15 15:29:08.170 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6747 (SRP1/1) Down, hold time expired
Jul 15 15:29:09.170 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6747 (SRP1/1) Up, new adjacency
Jul 15 21:51:33.520 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6747 (SRP1/1) Down, hold time expired
Jul 15 21:51:34.520 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6747 (SRP1/1) Up, new adjacency
.Jul 16 01:20:53.202 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6750 (SRP1/1) Down, hold time expired
.Jul 16 01:20:54.198 BST: %CLNS-5-ADJCHANGE: ISIS: Adjacency to GM6750 (SRP1/1) Up, new adjacency
The weird thing is this happens for just a second and then it recovers.
TDP log message below:
Jul 14 03:59:13.806 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.142:0 is DOWN
Jul 14 03:59:18.498 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.142:0 is UP
Jul 14 16:19:53.448 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.142:0 is DOWN
Jul 14 16:19:54.664 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.142:0 is UP
Jul 14 17:51:22.028 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.128:0 is DOWN
Jul 14 17:51:26.080 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.128:0 is UP
.Jul 16 06:44:14.712 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.128:0 is DOWN
.Jul 16 06:44:22.464 BST: %LDP-5-NBRCHG: TDP Neighbor 145.233.101.128:0 is UP
show isis neighbors below:
System Id Interface SNPA State Holdtime Type Protocol
GM6744 SR1/1 0009.7c21.4b80 Up 21 L2 IS-IS
Area Address(es): 49.0001
IP Address(es):
Uptime: 1w2d
NSF capable
GM6750 SR1/1 000a.b7b6.9b80 Up 23 L2 IS-IS
Area Address(es): 49.0001
IP Address(es):
Uptime: 07:19:47
NSF capable
GM6747 SR1/1 000a.b7b6.ab80 Up 23 L2 IS-IS
Area Address(es): 49.0001
IP Address(es):
Uptime: 10:49:06
NSF capable
GM6736 SR1/1 0009.7cf9.6a00 Up 27 L2 IS-IS
Area Address(es): 49.0001
IP Address(es):
Uptime: 2d20h
NSF capable
GM6741 SR1/1 0009.7c49.cc00 Up 22 L2 IS-IS
Area Address(es): 49.0001
IP Address(es):
Uptime: 2d07h
NSF capable
GM6740 SR1/1 0009.7c49.cc80 Up 27 L2 IS-IS
Area Address(es): 49.0001
IP Address(es):
Uptime: 1y51w
System Id Interface SNPA State Holdtime Type Protocol
NSF capable
GM6738 SR1/1 0009.b775.3880 Up 27 L2 IS-IS
Area Address(es): 49.0001
IP Address(es):
Uptime: 3d04h
NSF capable
show tdp neighbor below:
GM6749#sh tag-switching tdp neighbor | i Up
Up time: 1y18w
Up time: 2w0d
Up time: 2w0d
Up time: 4d06h
Up time: 2d12h
Up time: 1d16h
Up time: 01:57:43
I'm a bit puzzled why the adjacencys are failing as the holdtimer is set to 30 secs.
Thanks for the help.
Cheers
Kev
07-19-2010 04:21 AM
is this filtered log w r t ISIS or the complete one , is there any other physical lay
er issues possibly ?
07-21-2010 01:19 PM
Hello Kevin,
ISIS hello packets are padded to CLNS MTU with default settings this is different from what happens with OSPF hello packets that are small packets.
Also ISIS packets are not IP packets so if any form of scheduler is used on the SRP ring there is the risk ISIS packets are not treated well
you could try to reduce clns mtu in interface mode and to disable hello padding (not sure if this is done in router isis process or interface level)
Hope to help
Giuseppe
07-23-2010 02:02 AM
Guisar,
Thanks for the advice.
I forgot to add that TDP also loses its neighbors as well.
More frequently than ISIS.
There is a QOS policy on the SRP interface so there is a scheduler active.
I had already disabled hello padding.
Thanks
Kev
07-23-2010 02:28 AM
To add.
Dont IGP's use the pak priority so they always go before anything else?
Cheers
Kev
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