[c-nsp] Fiber issue, banging my head.

[Peter Nyamukusa]

Hi,

What type of Media converters are you using? What speed are they running at?
Have you tried to use different media converters?

I have ran into something similar to this it started all of a sudden I used
to get input and CRC errors on my 7206 router, the fibre was terminating on
a 2950 switch. The error will accumulate until the port on the switch shuts
down then when you reset the switch the link works for several hours before
shutting down again. It was very difficult for us to identify this because
the switch belonged to a last mile provider and we had suggested to them to
change the media converters which they were not reluctant to do saying that
this setup has been working for years.
Surprisingly when they eventually changed the media converters on both ends
the errors completely vanished and the link has been fine ever since

Hope this helps

Cheers

Peter  


> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On
> Behalf Of Tom Storey
> Sent: Friday, September 07, 2007 12:13 PM
> To: Drew Weaver; cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Fiber issue, banging my head.
> 
> In my experience when you have the same number of CRC errors as you do
Input
> errors it generally indicates a duplex mismatch.
> 
> Try hard coding speed (where applicable) and duplex at both ends and see
> what happens.
> 
> Its already been suggested to turn autoneg off, which may also help.
> 
> Cheers,
> Tom
> 
> ----- Original Message -----
> From: "Drew Weaver" <drew.weaver at thenap.com>
> To: <cisco-nsp at puck.nether.net>
> Sent: Friday, September 07, 2007 3:41 AM
> Subject: [c-nsp] Fiber issue, banging my head.
> 
> 
> > Hi there.
> >
> > We are trying to connect a Catalyst 6509 connected via fiber to two GSR
> 12000 routers.
> >
> > When we connect the switch to the router(s) via G5/1 and G5/2 (on the
> Supervisor 720) we get input errors on the Router (the GSR side), the line
> goes up/up but we see:
> >
> > Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
> >  1668 input errors, 1668 CRC, 0 frame, 0 overrun, 0 ignored
> >
> > The throughput between the two pairs is also terribly slow.
> >
> > We have tried different cards in the GSRs, we have tried different fiber
> cables.
> >
> > The configurations are very simple:
> >
> > --Pair #1--
> > Cat side:
> >
> > interface GigabitEthernet5/1
> >  description Gig-E to GSR #1
> >  ip address 192.168.0.34 255.255.255.252
> > end
> > GSR side:
> > interface GigabitEthernet6/0
> >  description Gig-E to Catalyst 4
> >  ip address 192.168.0.33 255.255.255.252
> >  no ip directed-broadcast
> >  negotiation auto
> > end
> >
> > --Pair #2-
> > Cat side:
> > interface GigabitEthernet5/2
> >  description Gig-E to GSR #2
> >  ip address 192.168.0.106 255.255.255.252
> > end
> > GSR side:
> > interface GigabitEthernet6/0
> >  description Gig-E to Catalyst 4
> >  ip address 192.168.0.105 255.255.255.252
> >  no ip directed-broadcast
> >  negotiation auto
> > end
> >
> > we have 3 other catalysts connected to these two GSRs in a similar
fashion
> (exactly the same) and the GSRs do not show errors.
> >
> > Any idea why the errors would only show on the GSR side?
> >
> > Thanks for any advice.
> >
> > -Drew
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