[c-nsp] 2651xm packet loss with 200 ft ethernet link

[Andy Dills]

Just a quick followup, as I got this resolved this morning (after seeing 
the odd behavior continue on additional fastethernet interfaces on a 
replacement router).

Turns out, the issue was ultimately with the wiring between the Level3 
fuji ports and the jack panel where they officially hand us off the 
circuits.

We bypassed the panel, terminating directly into their mux card, and the 
packet loss vanished.

Still doesn't tell me why the 7200 interface was able to power it's way 
through whatever was wrong...it's an older PA-FE-TX so I'm guessing the 
old DEC chips are cranked up all the way to deal with older crappy wiring, 
and it had enough juice to power through whatever is faulty in the 
jackpanel.

Oh well. Fixed now. Thanks for all the replies on and off list suggesting 
avenues for narrowing down the problem.

Andy

On Fri, 28 Dec 2012, Andy Dills wrote:

> 
> I'm having a weird problem that I can't quite seem to wrap my head around.
> 
> I have customer who has a 2651XM that we're hooking up to a Level3 
> (copper) ethernet circuit. Because of the distance between our telco 
> handoff and his rack, he has about 200 feet. Which shouldn't be a problem. 
> 
> However, we were seeing tremendous packet loss. After determining the 
> errors were coming from this end, and testing and replacing everything in 
> the path, we finally tried moving the router into the telco handoff room 
> so we could try to eliminate a lot of variables. With a short patch cable, 
> it worked fine, no packet loss.
> 
> So, we made a 200 ft cable to simulate the issue, and hooked it up to the 
> router while it sat next to the Level3 handoff...major packet loss again. 
> We tried the other fastethernet interface on the 2651...same problem.
> 
> However, if I take that same cable and terminate it into one of our 7200s, 
> we get zero packet loss.
> 
> In sum:
> 
> This 2651xm with long cable, major packet loss
> This 2651xm with short cable, works fine
> Our 7200 with the same long cable, works fine
> 
> What's going on here? Is the controller in the 2651xm failing? Perhaps not 
> producing enough voltage?
> 
> Thanks,
> Andy
> 
> ---
> Andy Dills
> Xecunet, Inc.
> www.xecu.net
> 301-682-9972
> ---
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---
Andy Dills
Xecunet, Inc.
www.xecu.net
301-682-9972
---