3750- is working but cant telnet and memory full msg

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Jan 2nd, 2010
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I have a big LAN of more than 500 cisco devices. Problem is with one of 3750 switch. its working and its child switches are also working. but when i try to telnet it, its memory full msg comes and also seems to be down in Cisco Network Assistant. I cant restart this switch also. need urgent attention plz

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glen.grant Sat, 01/02/2010 - 05:18
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    You are not the first person to see this and it's something cisco needs to address seeing the widespread deployment of this model switch . I can only speculate as to the cause but it may have to do with stackmaster switch having the complete responsibility for the whole stack for configurations and all the other functions of the switch except it has to do it for a whole stack which could be 7 or 8 switches and if it does not release memory like it should it creates a memory leak and eventually the memory resources run out.  We have seen this on a stack and unfortunelty the only way to recover this is to reload the stack which is obviously disruptive and a poor fix to a problem .  In the stack we saw it in there is only about 6 vlans and 6 SVI's configured for the whole and not ver many acl's etcc that might chew up memory.   I have heard and seen other users complaining about the same issue.

Hi Sajid

I have the same issue. a few stacks of C3750 form my core and distribution networks. Since the last few weeks, I experience exactly the same as you describe.

CNA is blind, telnet isnt working, and when connecting using the console the only message it can get out is that its memory is full.

A collegue of mine found out that it can be the combination of IOS and the HTTP server (needed for CNA...) so I will look for a new IOS, and disable the http server in the mean time

Did you solve it?



sumitava123 Fri, 09/24/2010 - 08:17
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Hi ,

It is normally caused by some bug on the IOS . The only solution is to reload the  switch. Then keep checking the process utilisation and keep a track of the  processes which is continuously using most of the memory. Along with that open a TAC case aswell.

Hope this helps


krahmani323 Fri, 09/24/2010 - 08:44
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Hi All,

I have also met this issue some times. Impossible to log on 3750 (for 2960 also) with following message % Low on memory; thy again later % . CNA was used.

Depending on the IOS version we shoul match this bug :

CSCsz79652            Bug Details

Memory leak in *dead* memory
A memory leak may be seen in *Dead* memory.

This issue occurs in IOS version 12.2(50)SE and l2.2(50)SE1.  IOS version  12.2(44)SE is not affected.

The problem occurs when using Cisco Network Assistant to poll the device. 
ip http server< /CmdBold> or ip http secure-server< /CmdBold> need to be enabled for the leak to occur.

Disable the http server or stop CNA from polling the device.



rolfwolff Tue, 12/14/2010 - 04:39
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Any news about it?

Thank you.

Kind Regards,



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