[c-nsp] Sup-720 fabric failures

Chuck Church chuckchurch at gmail.com
Fri Jul 5 12:54:12 EDT 2013


Anyone remember the term 'chip creep'?  Came across that back in a Novell
Service and Support exam a LONG time ago.  Still relevant!

Chuck

-----Original Message-----
From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Mack
McBride
Sent: Friday, July 05, 2013 12:22 PM
To: Phil Mayers; Robert Williams
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Sup-720 fabric failures

This is actually a common fault in electronics (not just routers).
As the device cools, improper solder connections separate causing issues
(ie. Something isn't making good contact).
As the device heats up the components expand and restore contact and
everything works fine.
This is in fact a fault.  Under normal conditions the device should be able
to function as long as you don't get condensation and you don't freeze the
capacitors (which freeze somewhere below 0C).
Obviously fluctuating the temperature will make the situation worse as the
poor connection eventually becomes no connect from shrinking and expanding.

LR Mack McBride
Network Architect

-----Original Message-----
From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Phil
Mayers
Sent: Friday, July 05, 2013 5:25 AM
To: Robert Williams
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Sup-720 fabric failures

On 05/07/13 12:22, Robert Williams wrote:
> Slightly warmer than that, a cosy 15 degrees Celsius I'm afraid...

That's really weird. We have operated sup720 in places that cool.

> Any ideas?

None spring to mind, beyond a really odd hardware fault.
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