Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Can't turn on ISIS

I have 2610 router running IOS c2600-ik2s-mz.121-19.bin (IP PLUS) and 4500 router running IOS c4500-is-mz.113-11a.bin (IP PLUS). Both of them won't let me turn on ISIS. When i run the command "ROUTER then ? there will be an option for ISIS that tells me that the IOSs do support ISIS. It takes the command, but it will not move to the next level (Config-router), it stays on the the same mode (Config).

any idea?


New Member

Re: Can't turn on ISIS


The IP Plus feature set for 4500 and 2600 doesnt support ISIS.

You must run at least enterprise or provider feature set.

The IP plus have the command, but it will not take effect:

I guess that some of the feature sets have the same code base and the CLI is the same. BUT, the feature is not implemented.

Change to another feature set and it will work.

New Member

Re: Can't turn on ISIS

In 4500, I only have 20MB of RAM and 8MB of Flash and 2610, I have 48MB of RAM and 8MB of Flash. What IOS version I can run in 12.1 series to support IP/RIP/EIGRP/OSPF/BGP with ISIS and DLSW Feature Sets.


New Member

Re: Can't turn on ISIS

Hi again,

Your routers cant place a 12.1 enterprise or provider code on 8 MB flash or run thoose images on 20 MB RAM. 48 RAM isnt any probs.

You will need at least 16 MB Flash when running 12.1.

12.0 can handle 8 MB Flash, but 20 RAM isnt gonna work for you.

Upgrade your memory if you gonna run 12.1/0 Enterprise or Provider.


New Member

Re: Can't turn on ISIS


For IS-IS first uprade your Router IOS to new ver and after

first on config mode

R1(config)#clns routing

R1(config)#router isis


R1(conft-int)#ip router isis


Mehmood Sajid

CreatePlease login to create content