IS-IS Routers not establishing adjacency

Hi,

I am working through an IS-IS configuration in the SYBEX BSCI book. I
followed the example configs exactly but my routers can not establish
adjacency. Any IS-IS gurus with any ideas?

I don't want to post configs yet as the config from the sample chapter
is very straightforward. I'm probably missing a trick.

Thanks

 

You're not giving any information to go on. How are we supposed to know what
you have configured?

 

MTU mismatch comes first to my mind.I don't know what is in BSCI book, so
without seeing what have you configured there are many guesses. Did you
configure clns routing? did you configure 'clns routing', is-is routing
process with NET, and 'ip router isis' on the interfaces?

'debug isis adj' should give you some idea what might be wrong

Kind regards,
iLya

 

I thought it may be a problem with MTU sizes but the mtu size used by
RouterA and RouterB are the same.

OK, here is the scenario and config:

Two routers - RouterA and RouterB connected across a serial interface.

Config for Router A - level 1
----------------------------
RouterA#show run
Building configuration...

Current configuration : 640 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname RouterA
!
!
ip subnet-zero
!
clns routing
!
!
!
interface Ethernet0
ip address 192.168.50.1 255.255.255.0
ip router isis
clns router isis
no shutdown
!
interface Ethernet1
no ip address
shutdown
!
interface Serial0
no ip address
!
interface Serial0.1
ip address 192.168.40.1 255.255.255.0
ip router isis
clns router isis
!
interface Serial1
no ip address
!
router isis
net 01.0000.0000.0001.00
is-type level-1
!
ip classless
no ip http server
!
!
!
line con 0
exec-timeout 0 0
line aux 0
line vty 0 4
login
!
end

Config for RouterB - level-1-2
--------------------------
RouterB#show run
Building configuration...

Current configuration : 1043 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname RouterB
!
!
ip subnet-zero
!
clns routing
!
!
!
interface Serial0
no ip address
shutdown
!
interface Serial1
no ip address
clockrate 64000
!
interface Serial1.1
ip address 192.168.30.1 255.255.255.0
ip router isis
!
interface Serial2
no ip address
clockrate 64000
!
interface Serial2.1
ip address 192.168.40.2 255.255.255.0
ip router isis
clns router isis
!
router isis
net 01.0000.0000.0002.00
!
ip classless
no ip http server
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
end

On RouterA, here is the output of show clns neighbor and debug isis
adj:
RouterA#show clns neighbor

RouterA#
01:29:09: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:29:16: ISIS-Adj: Sending serial IIH on Serial0.1, length 1499
01:29:18: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:29:25: ISIS-Adj: Sending serial IIH on Serial0.1, length 1499
01:29:25: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:29:33: ISIS-Adj: Sending serial IIH on Serial0.1, length 1499
01:29:35: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:29:41: ISIS-Adj: Sending serial IIH on Serial0.1, length 1499show
clns neighb
or
01:29:43: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497

RouterA#
RouterA#
RouterA#
RouterA#show clns int e
01:29:51: ISIS-Adj: Sending serial IIH on Serial0.1, length 1499 0
Ethernet0 is up, line protocol is up
Checksums enabled, MTU 1497, Encapsulation SAP
ERPDUs enabled, min. interval 10 msec.
RDPDUs enabled, min. interval 100 msec., Addr Mask enabled
Congestion Experienced bit set at 4 packets
CLNS fast switching enabled
CLNS SSE switching disabled
DEC compatibility mode OFF for this interface
Next ESH/ISH in 0 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x0, local circuit ID 0x1
Level-1 Metric: 10, Priority: 64, Circuit ID: RouterA.01
Number of active level-1 adjacencies: 0
Next IS-IS LAN Level-1 Hello in 7 seconds
RouterA#

Some debug on RouterB:
01:36:46: ISIS-Adj: Sending serial IIH on Serial2.1, length 1499ug isis
a
01:36:49: ISIS-Adj: Sending serial IIH on Serial1.1, length 1499dj
IS-IS Adjacency related packets debugging is off
RouterB#
RouterB#show clns int s2.1
Serial2.1 is up, line protocol is up
Checksums enabled, MTU 1500, Encapsulation HDLC
ERPDUs enabled, min. interval 10 msec.
RDPDUs enabled, min. interval 100 msec., Addr Mask enabled
Congestion Experienced bit set at 4 packets
CLNS fast switching enabled
CLNS SSE switching disabled
DEC compatibility mode OFF for this interface
Next ESH/ISH in 16 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x0, local circuit ID 0x100
Level-1 Metric: 10, Priority: 64, Circuit ID: RouterB.00
Number of active level-1 adjacencies: 0
Level-2 Metric: 10, Priority: 64, Circuit ID: RouterB.00
Number of active level-2 adjacencies: 0
Next IS-IS Hello in 2 seconds

 

That won't work with sub-interfaces when main serial interface uses HDLC -
the router doesn't know where to deliver packets once they reach the
router's main interface. Configure IP directly on the main interface.

Kind regards,
iLya

 

This worked. The example in the book was configured for FRAME-RELAY.

Many Thanks

 

with Frame-relay sub-interfaces surely will work because there is DLCI to
distinguish between sub-interfaces.

Kind regards,
iLya

 

When using IS-IS with frame relay, you will also have to add a frame
relay map for the CLNS protocol for IS-IS to work.

Cisco da Gama
http://ciscostudy.blogspot.com

 

Have you solved it yet?

Xangadib