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New Member

Enabling IS-IS on 2500 not working

I'm working on my CCNP recertfication, and working through the 642-801 Sybex BSCI book. Since I don't have any ability to do hands-on IS-IS, I'm relying on using the 2501's and 2610's in my lab for IS-IS.

Here's my dilema. The hands-on lab says to enable IS-IS. When issuing the command "RouterA(config)#router isis", it should drop you into "router mode" like this - " RouterA(config-router)# like OSPF and EIGRP. Then next command I want to enter is the "net" command. However on my 2500's and 2600's, none of them drop me into 'router mode' after enabling IS-IS, and I can't find anywhere to enter the "net" command. One 2600 is running 12.2 code, and the others running 12.0'ish code.

Is it me or is Sybex wrong (again)? I went back into the chapter to verify the commands, which were the same. Can someone help with this? I'd be greatly appreciated.




Re: Enabling IS-IS on 2500 not working

Hi Jim,

What you have encountered is a major annoyance with the parser. The parser lets you enter the 'router isis' command even if the IOS image does not support ISIS. That is the case with your image. ISIS is not supported with the basic feature sets. On the 2600s, you need at least the following:

For the 12.0s: Enterprise Plus feature set

For the 12.2s: Enterprise Plus feature set

The implication is, of course, more DRAM and flash. If you have sufficient DRAM, you can always TFTP boot your box if you don't have enough flash.

Hope that helps - pls rate the post if it does.


Cisco Employee

Re: Enabling IS-IS on 2500 not working

This is a sign that the feature set you currently use doesn't support ISIS.

Please the IOS Feature Navigator to find out, which IOS versions and feature sets support this feature.

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
México móvil: +52 1 55 8312 4915
Cisco México 
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Cuauhtémoc, Juárez
Ciudad de México, 06600
New Member

Re: Enabling IS-IS on 2500 not working

I greatly appreciate both posts! I accessed the IOS upgrade planner yesterday, but was unable to figure out which code supported Integrated IS-IS. The first post helps. The second post gave me a link that I used at a previous company, but couldn't remember the name.

I guess it's time to check out the memory on all routers and get them up to specs for the correct code.

Thanks again to both!