[c-nsp] Input errors, overrun & unknown protocols drops on LAN interface

[David Prall]

I'd say you have a lot of traffic with TTL 1 or a link-local multicast
address on the interface, if everything else is working correctly. Otherwise
you are process switching a lot of traffic.

Here are some pointers:
http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186
a0080094791.shtml

But, I would say that you have something like "no ip route-cache" configured
on the interface. You say it is a LAN interface, you talk about MPLS, are
there multiple LDP relationships on this interface, are you running RSVP for
TE on a LAN Segment?

David

--
http://dcp.dcptech.com


> -----Original Message-----
> From: Farooq Razzaque [mailto:farooq_mcp at hotmail.com]
> Sent: Tuesday, September 13, 2011 11:18 AM
> To: dcp at dcptech.com; david.rothera at gmail.com
> Cc: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] Input errors, overrun & unknown protocols drops on
> LAN interface
> 
> Dear David
> 
> Please find the resule of show buffer. can u pls analyse and help
> 
> 
> 
> <http://www.flamingtext.com/hmail.html>
> 
> 
> 
> 
> 
> 
> ________________________________
> 
> From: farooq_mcp at hotmail.com
> To: dcp at dcptech.com; david.rothera at gmail.com
> CC: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] Input errors, overrun & unknown protocols drops on
> LAN interface
> Date: Tue, 13 Sep 2011 20:49:14 +0600
> 
> 
> Dear David
> 
> I increased the hold on Queue to size 3500 but the input error and
> input queue drops are there . May be the frequency of increasing is
> reduced but it is still there.
> 
> 
> 
> <http://www.flamingtext.com/hmail.html>
> 
> 
> 
> 
> 
> 
> > From: dcp at dcptech.com
> > To: farooq_mcp at hotmail.com; david.rothera at gmail.com
> > CC: cisco-nsp at puck.nether.net
> > Subject: RE: [c-nsp] Input errors, overrun & unknown protocols drops
> on LAN interface
> > Date: Tue, 13 Sep 2011 09:40:49 -0400
> >
> > To minimize the input drops you can increase the hold-queue. Another
> issue
> > to look at is the buffers as well, most likely have misses and
> failures
> > there. The flushes are caused by SPD, which are control plane packets
> that
> > need to make it to the processor so they are put ahead of everything
> else in
> > the input queue.
> >
> > David, a different one.
> >
> > --
> > http://dcp.dcptech.com
> >
> >
> > > -----Original Message-----
> > > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > > bounces at puck.nether.net] On Behalf Of Farooq Razzaque
> > > Sent: Tuesday, September 13, 2011 9:18 AM
> > > To: david.rothera at gmail.com
> > > Cc: cisco-nsp at puck.nether.net
> > > Subject: Re: [c-nsp] Input errors, overrun & unknown protocols
> drops on
> > > LAN interface
> > >
> > >
> > > Dear David
> > >
> > > How can we resolve this then
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > > Subject: Re: [c-nsp] Input errors, overrun & unknown protocols
> drops
> > > on LAN interface
> > > > From: david.rothera at gmail.com
> > > > Date: Tue, 13 Sep 2011 14:04:57 +0100
> > > > CC: nick at foobar.org; cisco-nsp at puck.nether.net
> > > > To: farooq_mcp at hotmail.com
> > > >
> > > > Input drops are usually caused by the input queue filling up and
> then
> > > tail drops occurring because there is no more space for new packets
> in
> > > the queue.
> > > >
> > > > I've seen this happen where you have an upstream device trying to
> > > send packets faster than the downstream device can process them.
> > > >
> > > >
> > > > On 13 Sep 2011, at 13:54, Farooq Razzaque wrote:
> > > >
> > > > >
> > > > > Dear Nick
> > > > >
> > > > > Thanks for your reply.
> > > > >
> > > > > What does input error means ?
> > > > >
> > > > > I am also having the drops in Input queue
> > > > >
> > > > >
> > > > >
> > > > > Input queue: 0/75/3267688/769 (size/max/drops/flushes); Total
> > > output drops: 0
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >> Date: Tue, 13 Sep 2011 12:18:05 +0100
> > > > >> From: nick at foobar.org
> > > > >> To: farooq_mcp at hotmail.com
> > > > >> CC: cisco-nsp at puck.nether.net
> > > > >> Subject: Re: [c-nsp] Input errors, overrun & unknown protocols
> > > drops on LAN interface
> > > > >>
> > > > >> On 13/09/2011 10:13, Farooq Razzaque wrote:
> > > > >>> I am facing the input errors, overrun & unknown protocols
> drops
> > > on LAN
> > > > >>> interface-Gi0/0 (having sub-interface) on MPLS router.
> > > > >>
> > > > >> port overruns mean that your router is receiving data faster
> than
> > > it can
> > > > >> handle. You either need a faster router than a 3800 series or
> else
> > > larger
> > > > >> input buffers.
> > > > >>
> > > > >> Unknown protocols means that your switch is sending data that
> the
> > > router
> > > > >> doesn't understand. Maybe LLDP or something? Or some other odd
> LAN
> > > protocol?
> > > > >>
> > > > >> Nick
> > > > >
> > > > > _______________________________________________
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> > > >
> > >
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