Stacking of Cisco Catalyst 3750

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Jan 20th, 2010
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Hi Everyone


Is there a problem incase we stack different models of cisco catalyst switches as we have stacked two models with details as follows




Two different models of switches in the stack are

  • WS-C3750G-24TS-E
  • WS-C3750-48TS-E


Also of late at times we are unable to access the stack via telnet / snmp and remedy and remedy we have been following is taking hard reboot of the switches ( but it is not always the best way keeping into consideration that server farm is live on one of the designated vlans.


Is it something to do with

IP input process and  virtual EXEC process

these processes are utilizing more CPU for 5 sec, reason behind this is VTY(telnet) connections.

PID  CPU Time    Process

191  10.69%            IP Input

208  59.03%            Virtual Exec


Kindly help


Regards

Sohail Sarwar

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Leo Laohoo Wed, 01/20/2010 - 19:12
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As long as the entire stack has the same IOS version and feature set.


If your stack is experiencing high CPU utilization, what is the version they are running on?

Reza Sharifi Wed, 01/20/2010 - 19:13
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Hello Sohail,


With 3750 switches, you can mix and match any model you want and stack them together.  Another word, you can have a stack of 3750s that has regular 3750, 3750G and 3750E.


As for your second question, can you provide "sh ver"?

Also do you see any crash files in your flash?

Can you provide "sh process cpu sor"

If you have configured every thing correctly, it may be a bug in the IOS that causes high CPU.


HTH

Reza

krishnakumarr Wed, 01/20/2010 - 22:54
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Hi


From the logs I did not find any clues it is fine


Can you check the process following commnd


show process cpu | ex 0.00  ( pl check several period of time provide output )


show process cpu history


and where this switch has been deployed it is  handling huge traffic ( core / metro )



regards

krishna kumar

sohail_sarwar Thu, 01/21/2010 - 00:06
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Hi Krishna kumar


Kindly find attached the output of commands as an attachment



sh processes cpu | excluding 0.00% ( command executed a no of times)


and show processes cpu history




We have utilised the Swictch at Core Level ( in Data Centre) where is we have replication link between DC and DR terminated on one of the Vlans

Also all access locations having Broadband Vsat Link are terminated on the same stack using GRE Tunnels



Regards

Sohail Sarwar

krishnakumarr Thu, 01/21/2010 - 04:06
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Hi


I went through the logs now the switch is working fine , pl clarify my questions


1, How frequent you are facing this issue

2. May be you will get slow responce when cpu utilization is high

3. you can monitor the same next couple of hours ( my observation  during the short time the CPU intrupt more times /  if the percentage is high

    the device perfomance also will degrade


regards

krishna kumar

sohail_sarwar Thu, 01/21/2010 - 08:42
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Hi Krishna


The answer to queries raised by you are as follows


1, How frequent you are facing this issue


answer) we have faced this issue thrice since last 6 to 8 months and remedial action taken by reboot of stack


2. May be you will get slow responce when cpu utilization is high


answer) OK Fair enough but what are the processes that choke CPU utilisation


and what is the resolution /way forward to solve this issue



do we need hardware upgradation to 6500 series or IOS upgrade from current version which although we upgraded few months back only



regards

Sohail Sarwar

krishnakumarr Fri, 01/22/2010 - 03:05
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Hi


Try to upgrade the latest IOS version SE53 and monitor the switch still you are facing same issue


Upgrade the hardware to 6500 with sup 720


regards

krishna kumar

krishnakumarr Fri, 01/22/2010 - 03:07
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Hi


If you have the hardware 6500 replace it other wise you can go with 4500- E with sup 6E


regards

krishna

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