[c-nsp] Ethernet Freezeup

[Andre Beck]

Hi Jon,

On Tue, Apr 08, 2008 at 10:35:36AM -0500, jon.hartman at verizon.com wrote:
> Is it possible that your interface is getting wedged?
> 
> http://www.cisco.com/en/US/products/hw/iad/ps397/products_tech_note09186a0
> 0800a7b85.shtml

Hard to say without having a "sh int fa0/0" from when the issue hit. The
description says that only a reload would clear this kind of problem,
but it's old and things may have changed. My Fa0/0 input queue looks like

  Input queue: 0/75/0/2 (size/max/drops/flushes); Total output drops: 0

and I ponder what the two flushes may be. I did indeed have exactly two
occasions of the interface hanging that could be cleaned with a clear int.
Further, just giving it a clear int when it is running normally doesn't
increment that counter. When it strikes again (hopefully auto-healed by my
new EEM applet) and that counter increments, it's probably indeed an input
queue overrun (wedged).

BTW, there's also a chance of the switch beeing involved. In my case, it's
a 3550-12T and it's actually seeing an occasional CRC error (and the router
is counting occasional collisions) even though it's just 3m Cat5e cabling,
just 100BaseTX and hardwired to full duplex (silly IO-FE and PA-FE-TX
missing a decent Nway, running the Tulip without any auto negotiation).
Hard to guess whether this is any problem. Seems other chassis with these
interfaces count similar CRCs and collisions without any issues for years.

Thanks for the hint,
Andre.
-- 
   Real men don't make backups of their mail. They just send it out
    on the Internet and let the secret services do the hard work.

-> Andre Beck    +++ ABP-RIPE +++      IBH IT-Service GmbH, Dresden <-