Strange IS-IS adjacency problem

From: John Wong (johnwk@unimelb.edu.au)
Date: Sun Oct 24 2004 - 11:17:40 GMT-3


Hi all,

Need help from you Gurus on a strange IS-IS problem I am encountering
at the moment. Any help is much appreciated.

I am getting the below message on a hub router in a FR network
configured to run IS-IS :-

Oct 24 21:19:13 SGT: %CLNS-3-BADPACKET: ISIS: LAN L2 hello, packet (1500) or wire (988) length invalid from DLCI 703 (Serial0/2.1)

The adjacency is stuck at the Init stage in R3 (spoke) and not appearing
at all in R7 (hub).

Strange thing is that I have 2 identically configured routers (R1 & R3)
as the spokes and the hub router (R7) can establish adjacency with one of
them (R1) but not the other (R3). Both R1 & R3 are of the same hardware
platform and runs the same version of IOS image.

Relevant configuration as below :-

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
hostname R1
!
interface Serial0
 no ip address
 encapsulation frame-relay
 no frame-relay inverse-arp
!
interface Serial0.1 multipoint
 ip address 192.168.1.1 255.255.255.0
 ip router isis
 frame-relay map clns 107 broadcast
 frame-relay map ip 192.168.1.3 107 broadcast
 frame-relay map ip 192.168.1.7 107 broadcast
!
router isis
 net 47.0200.0102.5500.0001.00

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
hostname R3
!
interface Serial0
 no ip address
 encapsulation frame-relay
 no frame-relay inverse-arp
!
interface Serial0.1 multipoint
 ip address 192.168.1.3 255.255.255.0
 ip router isis
 frame-relay map clns 307 broadcast
 frame-relay map ip 192.168.1.1 307 broadcast
 frame-relay map ip 192.168.1.7 307 broadcast
!
router isis
 net 47.0000.0102.5500.0003.00

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
hostname R7
!
interface Serial0/2
 no ip address
 encapsulation frame-relay
 no frame-relay inverse-arp
!
interface Serial0/2.1 multipoint
 ip address 192.168.1.7 255.255.255.0
 ip router isis
 isis priority 120
 frame-relay map clns 703 broadcast
 frame-relay map clns 701 broadcast
 frame-relay map ip 192.168.1.1 701 broadcast
 frame-relay map ip 192.168.1.3 703 broadcast
!
router isis
 net 47.0100.0102.5500.0007.00

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

R1#sh clns neigh
System Id Interface SNPA State Holdtime Type Protocol
R7 Se0.1 DLCI 107 Up 7 L2 IS-IS

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

R3# sh clns neigh
System Id Interface SNPA State Holdtime Type Protocol
0102.5500.0007 Se0 DLCI 307 Init 9 L2 IS-IS

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

R7#sh clns neighbors
System Id Interface SNPA State Holdtime Type Protocol
R1 Se0/2.1 DLCI 701 Up 24 L2 IS-IS



This archive was generated by hypermail 2.1.4 : Sat Nov 06 2004 - 17:11:52 GMT-3