From: R&S Groupstudy (rsg@synergy-networking.co.uk)
Date: Fri Nov 21 2003 - 13:13:56 GMT-3
the designated router will form a pseudo node
do a route isis database level-1
you will see that the dis will have an entry twice for the network segment
look for the entry with the NSAP.01 This is the Pseudo node
eg
Core3#show isis d l1
IS-IS Level-1 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
Core3.00-00 * 0x00000002 0x9306 1005 0/0/0
Core3.01-00 * 0x00000001 0x720A 1009 0/0/0
Core3#
Adam
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Ken.Farrington@barclayscapital.com
Sent: 21 November 2003 16:09
To: jhays@jtan.com; OzgurG@garanti.com.tr
Cc: ccielab@groupstudy.com
Subject: RE: ISIS Hello Packet Problem
The DIS (rtr2) sends hellos every 1/2 iof the configured hello-interval. I
just checked this out.
so when you look at the hold times using the "show clns nei" command it's a
bit mis-leading, if they asked you to config this in the lab so i think is
quite important that you guys have explained this very well :)
Also, how do you know (via command line commands) which is the DIS. I
assume it's highest IP but can you see this in IOS?
Many thx, and a very interesting subject :))
R2#sh clns nei
System Id SNPA Interface State Holdtime Type
Protocol
4444.4444.4444 DLCI 254 Se1 Up 31 L1 IS-IS
R2#sh clns nei
System Id SNPA Interface State Holdtime Type
Protocol
4444.4444.4444 DLCI 254 Se1 Up 39 L1 IS-IS
R2#
R4#sh clns nei
System Id SNPA Interface State Holdtime Type
Protocol
2222.2222.2222 DLCI 452 Se0 Up 106 L1 IS-IS
R4#sh clns nei
System Id SNPA Interface State Holdtime Type
Protocol
2222.2222.2222 DLCI 452 Se0 Up 100 L1 IS-IS
R4#sh clns nei
System Id SNPA Interface State Holdtime Type
Protocol
2222.2222.2222 DLCI 452 Se0 Up 134 L1 IS-IS
R4#
Router 1
R2#debug isis adj
IS-IS Adjacency related packets debugging is on
R2#
06:09:11: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
R2#
06:09:25: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:09:27: ISIS-Adj: Sending L1 IIH on Serial1
06:09:38: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:09:51: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:10:05: ISIS-Adj: Sending L1 IIH on Serial1
06:10:05: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:10:19: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:10:31: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:10:44: ISIS-Adj: Sending L1 IIH on Serial1
06:10:45: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:10:57: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:11:09: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:11:21: ISIS-Adj: Rec L1 IIH from DLCI 254 (Serial1), cir type 1, cir id
4444.4444.4444.01
06:11:25: ISIS-Adj: Sending L1 IIH on Serial1
Router 2 (Assuming is the DIS)
06:09:22: ISIS-Adj: Sending L1 IIH on Serial0
06:09:24: ISIS-Adj: Rec L1 IIH from DLCI 452 (Serial0), cir type 1, cir id
4444.
4444.4444.01
06:09:35: ISIS-Adj: Sending L1 IIH on Serial0
06:09:48: ISIS-Adj: Sending L1 IIH on Serial0
06:10:02: ISIS-Adj: Sending L1 IIH on Serial0
06:10:03: ISIS-Adj: Rec L1 IIH from DLCI 452 (Serial0), cir type 1, cir id
4444.
4444.4444.01
06:10:16: ISIS-Adj: Sending L1 IIH on Serial0
06:10:28: ISIS-Adj: Sending L1 IIH on Serial0
06:10:41: ISIS-Adj: Rec L1 IIH from DLCI 452 (Serial0), cir type 1, cir id
4444.
4444.4444.01
06:10:42: ISIS-Adj: Sending L1 IIH on Serial0
06:10:54: ISIS-Adj: Sending L1 IIH on Serial0
06:11:06: ISIS-Adj: Sending L1 IIH on Serial0
06:11:18: ISIS-Adj: Sending L1 IIH on Serial0
06:11:23: ISIS-Adj: Rec L1 IIH from DLCI 452 (Serial0), cir type 1, cir id
4444.4444.4444.01
-----Original Message-----
From: Jonathan V Hays [mailto:jhays@jtan.com]
Sent: 21 November 2003 13:09
To: 'Ozgur Guler (Garanti Teknoloji)'
Cc: ccielab@groupstudy.com; Farrington, Ken: IT (LDN)
Subject: RE: ISIS Hello Packet Problem
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Ozgur Guler (Garanti Teknoloji)
Sent: Friday, November 21, 2003 7:53 AM
To: Jonathan V Hays
Cc: ccielab@groupstudy.com; Ken.Farrington@barclayscapital.com
Subject: RE: ISIS Hello Packet Problem
Jonathan,
--------------------
From the above information, I would guess that the DIS (designated
intermediate system) ignores the "isis hello-interval" command and sends
at 3.3 seconds (plus or minus 25% jitter) regardless
---------------------
did you check this out?
what i found is DIS sends hellos with an interval (1/3 of what you have
configured as hello-interval)-the jitter...
Ozgur
========
This is interesting behavior. Does anyone know of a mention in a
specification that would legitimize these findings? (Is Cisco following
spec?)
Jonathan
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