HELP: Configuring ISIS on a CLNS environment

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Jul 9th, 2007
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Dear All,

I have a 2610 router that is running OSPF and ISIS, I want to connect the router to an SDH NE (Alcatel) which is not running IP. However it has an NSAP address. Is there any special configuration on the router's interface connected to the NE?

I've already configured the interface to suppport clns. Below is the configuration that i made on the router.

Clns routing


Router isis

net 39.682F.8000.0000.0000.0001.0003.3333.3333.3333.00

is-type level-1-2

!interface FastEthernet0/0

ip address

ip router isis

duplex auto

speed auto

clns router isis

isis circuit-type level-1


interface Serial0/1

ip address

ip router isis

clockrate 64000

clns router isis

isis circuit-type level-2-only

I tried to ping the node using ping clns 39.682F.8000.0000.0000.0001.0003.0020.6001.4314.1D but it failed, however when I ping the neighbor router (3725) it was connecting so i assume that isis is ok between the two routers.

I think I am missing something...

Can anybody help me out.


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chrihussey Mon, 07/09/2007 - 06:09
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I'm not sure and this is just a guess, but have you tried adding "clns enable" to the interface facing the Alcatel system?

wireheadz Mon, 07/09/2007 - 22:32
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tnx for your reply. I've already done that and it was not working. so, I removed it. Its really odd coz when i tried to view the neighbors(show clns neighbors) the system id of the NE is actually displayed and its state is up. However when i tried to ping (ping clns XX.XXXX....XX) the NE's NSAP address, it was not reachable. Below are some show commands that Ive done on the router.

AREA3ECCM#sh clns neig

System Id Interface SNPA State Holdtime Type Protocol

Area1MAIN Se0/1 *HDLC* Up 23 L2 IS-IS

0020.6001.4314 Fa0/0 0020.6001.4314 Up 163 IS ES-IS

AREA3ECCM#sh isis route

IS-IS Level-1 Routing Table - version 97

System Id Next-Hop Interface SNPA Metric State

0020.6001.4314 0020.6001.4314 Fa0/0 0020.6001.4314 10 Up


AREA3ECCM#sh clns protocol

IS-IS Router:

System Id: 3333.3333.3333.00 IS-Type: level-1-2

Manual area address(es):


Routing for area address(es):


Interfaces supported by IS-IS:

FastEthernet0/0 - OSI - IP

Serial0/0 - OSI - IP

Serial0/1 - OSI - IP

Note: The Alcatel NE is connected via Fa0/0


chrihussey Tue, 07/10/2007 - 08:44
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The only thing I can suggest is to remove all the ISIS configuration from the F0/0 interface and add the "clns enable" and then try it. Below is the explanation:

"clns enable" - You also must enable ISO CLNS for each interface you want to pass ISO CLNS packet traffic to end systems, but for which you do not want to perform any dynamic routing on the interface.

Unfortunately that's probably the best I can offer. Also, just in case you don't have this, I've attached a CLNS config PDF.



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