tcp adjust-mss

[tamer]

Hello All,

I need the command (ip tcp adjust-mss) to solve problems with l2tp tunnels. I have vxr 7206 with IOS 12.2(14)T , but I cant find the command. In which feature set should I find this command ?

[thisisshanky]

Its a interface mode command. First check under the interface.

[tamer]

yes I have already checked under the interface mode, it doesn't exist there, there is only (ip tcp compression-connections) & (ip tcp header-compression)

[thisisshanky]

The command used to be known as "ip adjust-mss" before it was changed to ip tcp adjust-mss. So its possible that the deprecated command exists. Check with ip a? and see what options it list..

Mean while I will check with Software advisor if that command is supported.

[Richard Burts]

According to notes that I found at this URL:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a00804247fc.html

it was introduced in 12.2(4)T as the syntax ip adjust-mss and in 12.2(8)T the syntax was changed to ip tcp adjust-mss. So if the router is running 12.2(14)T I would think that the command should be there. I did not find anything in the notes that indicated that there was a feature set dependency.

What interface were you trying to do this on. The notes indicate that it should be an Ethernet interface of some type.

HTH

Rick

[tamer]

First I amd sorry , I typed the ios version of another router. The version I have is 12.2(27) . The interface is fastethernet . there is no ip adjust-mss or ip tcp adjust-mss under it.

[Richard Burts]

Tamer

Actually this makes more sense knowing that you gave the version from another router. If the router you are trying on is running 12.2(27) which is main line code the command does not exist in that version. You would need to have something in the 12.2T train or in 12.3 (or perhaps 12.3T) to get this command. As I indicated in my previous post I do not see anything that indicates a feature set dependency, it is just a version issue. If you upgrade the router IOS to a version that has the command you will be able to use ip tcp adjust-mss.

HTH

Rick

[tamer]

yes you are right now I use ver 12.2(15)T17 and the command is working fine. but I faced another problem that the cpu has gotten much higher (almost triple) after I applied it as if like ip cef isnt working while it is enabled.

Note: I use this router to terminate l2tp vpdn sessions on it. any ideas about this?

[tamer]

when I serached for ios comparison between the 2 versions , I found that feature (CEF Switching for Routed Bridge Encapsulation) is missing in the new ios . would that be the problem cause of high cpu ?.

[Richard Burts]

Tamer

I doubt that this is the cause. You have not told us that your were using Routed Bridge Encapsulation. Is that part of the router config? Perhaps it would help if you would post the router config so we can analyze the problem more accurately.

HTH

Rick