[c-nsp] PPP encapsulation triggering LOF on DS3?

[Vinny Abello]

Actually, I'm sorry for the misinformation, but the majority of our clear 
channel DS3's are actually HDLC but they do all have scrambling enabled. I 
happened to check last night.

At 03:56 AM 11/19/2004, Vincent De Keyzer wrote:
>I also have a similar problem, but it's slightly different:
>* access router is 7500 with PA-2E3
>* CPE is 7200 with PA-E3
>* in between there are two transmission links that are chained: one E3 over
>SDH, and one E3 wireless link
>* everything works fine as long as CPE does not reload
>* when CPE reload, access router sees a LOF and line protocol stays down
>* disconnecting and reconnecting the coaxes on any of the routers, or
>setting then removing a loop on the SDH section (in any direction) fixes the
>problem
>
>I will try to see if going to HDLC or enabling scrambling helps.
>
>Thanks guys
>
>Vincent
>
>
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > bounces at puck.nether.net] On Behalf Of Vinny Abello
> > Sent: vendredi 19 novembre 2004 3:40
> > To: Kevin Graham
> > Cc: cisco-nsp
> > Subject: Re: [c-nsp] PPP encapsulation triggering LOF on DS3?
> >
> > That's interesting, as we have a DS3 with a certain provider running into
> > a
> > 7206VXR PA-T3, etc.... and the provider said their default encapsulation
> > type is PPP. We turned up the line and it looked ok and we could ping
> > across it no problem... as soon as we turned up BGP and had traffic
> > flowing
> > over it, it seemed almost like certain traffic was being blocked but not
> > all of it. After troubleshooting for quite some time, I suggested they
> > enable scrambling on the circuit. Once scrambling was enabled, everything
> > was pristine. We never tried HDLC as I don't think it would have made a
> > difference, but that's interesting to hear. All of our clear channel DS3's
> > on our network run with scrambling enabled (on our backbone and such). I
> > believe one is HDLC actually, but most are PPP but they all have
> > scrambling
> > enabled. I've never had good experiences without scrambling enabled but it
> > could just be my particular situations.
> >
> > At 08:46 PM 11/18/2004, Kevin Graham wrote:
> > >Just ran into a problem that I'm absolutely clueless on that I was
> > >hoping someone could share some insight..
> > >
> > >On a clear-channel DS3 terminating directly onto Cisco DS3 interfaces
> > >on both ends (PA-T3 on a 7200 and some GSR LC on the other) w/ PPP
> > >encapsulation link that had been good for several months went down.
> > >Interface would bounce down and then back up every 20s or so with an
> > >rxLOF, though line proto would never go up with a pile of CRC's on the
> > >7200 side (GSR side was always up/down with no errors). clockrate was
> > >osillating some though always in the 44M range.
> > >
> > >Loopbacks either way all came back clean and telco PM also looked
> > >good. However, whenever the link was normalized, the troublesome
> > >behavior would come back. After a round of loopbacks (of course using
> > >HDLC), both ends noticed that the link was running perfectly. Going
> > >back to PPP would cause the same problems..Went ahead and left it at
> > >HDLC and has been running fine.
> > >
> > >So... Is anyone aware of WTF could be going on that would cause PPP
> > >encapsulation to trigger a consistent LOF condition whereas HDLC does
> > >not? The only thing that comes to mind at all is perhaps scrambling
> > >(which is disabled), though as mentioned the line has been stable for
> > >months....
> > >
> > >Thanks.
> > >_______________________________________________
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> >
> >
> > Vinny Abello
> > Network Engineer
> > Server Management
> > vinny at tellurian.com
> > (973)300-9211 x 125
> > (973)940-6125 (Direct)
> > PGP Key Fingerprint: 3BC5 9A48 FC78 03D3 82E0  E935 5325 FBCB 0100 977A
> >
> > Tellurian Networks - The Ultimate Internet Connection
> > http://www.tellurian.com (888)TELLURIAN
> >
> > There are 10 kinds of people in the world. Those who understand binary and
> > those that don't.
> >
> >
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Vinny Abello
Network Engineer
Server Management
vinny at tellurian.com
(973)300-9211 x 125
(973)940-6125 (Direct)
PGP Key Fingerprint: 3BC5 9A48 FC78 03D3 82E0  E935 5325 FBCB 0100 977A

Tellurian Networks - The Ultimate Internet Connection
http://www.tellurian.com (888)TELLURIAN

There are 10 kinds of people in the world. Those who understand binary and 
those that don't.