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Intermittent from core switch to server farm(layer 2)

Hi Fellas,

i wanna ask about intermittent at my server farm. the freak me out is ping between user to application is good, however ping between user to ip management switch(server farm) is intermittent. i have no idea for this issue.

i have checked :

1. spanning tree (good)

2. layer 1 (good)

actually this issue is not critical because user still can access application without issue but while i ssh/telnet to switch always dc and dc again.

i am very appreciate for any suggestion

6 REPLIES 6
Joseph W. Doherty
Hall of Fame Expert

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Cisco switches don't prioritize ping responses, instead they prioritize forwarding frames.  What this means is pinging a switch's management IP often shows very variable response times.

PS:

To allow pings to be a more accurate indication of end-to-end latency, using Cisco device IPs, some devices support a special SLA responder, which will note when the ping query is received and indicate interior delay in the ping reply.  This allows a much more accurate ping response.

"Cisco switches don't prioritize ping responses" i aggreed with you but it still doesnt meant i hard to ssh/telnet my switch

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

I'm sorry, I didn't understand from your OP that "dc" was disconnect(?).  I.e. your question is more than just about erratic and variable ping times to the Cisco device?

Also a bit lost in understanding your post "but it still doesnt meant i hard to ssh/telnet my switch", specifically "i hard".  Could you clarify?

If you're saying you keep losing ssh/telnet access to your device, that's not normal.  Of course, it's not possible exec timeout is causing this, correct?

Hi Joseph,

sorry for my english, yes you are right i am keep losing ssh/telnet to my device. the strange is why intermittent is not affect to application but only happen in management ip switch (server farm).

topology

core switch - server farm - application

Can you confirm if the same is behind some firewalls i.e. you are behind the firewall - on other side ?

Second, what is ssh version in use ?

no firewell between core switch and server farm.

i am using ssh version 2.

i attached new picture, its very weird. i never face this issue before.