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checking Cisco 837 environmental conditions

One of our remote sites connected via ADSL using a Cisco 837 router has been having terrible ADSL stability problems recently.

Over the last few weeks the ATM0 interface is continually flapping - sometimes the link can be up for a couple of days without issue then suddenly connectivity goes again. E.g.

Jun 7 10:02:00.933: %LINK-3-UPDOWN: Interface ATM0, changed state to down

Jun 7 10:02:01.933: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, changed state to down

Jun 7 10:02:27.373: %DIALER-6-UNBIND: Interface Vi1 unbound from profile Di0

Jun 7 10:02:27.377: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to down

Jun 7 10:02:28.373: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, changed state to down

Jun 7 10:02:37.389: %LINK-3-UPDOWN: Interface ATM0, changed state to up

Jun 7 10:02:38.389: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, changed state to up

Jun 7 10:02:42.897: %LINK-3-UPDOWN: Interface ATM0, changed state to down

Jun 7 10:02:43.897: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, changed state to down

Jun 7 10:04:41.365: %LINK-3-UPDOWN: Interface ATM0, changed state to up

Jun 7 10:04:42.365: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, changed state to up

Jun 7 10:06:16.757: %DIALER-6-BIND: Interface Vi1 bound to profile Di0

Jun 7 10:06:16.761: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to up

Jun 7 10:06:18.381: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, changed state to up

Jun 7 10:06:51.893: %LINK-3-UPDOWN: Interface ATM0, changed state to down

It has also been syncing at extremely low rates for a lot of the time.

The latest telco engineer to visit has blamed our kit. The router was in a cupboard with not much airflow so I guess it is plausible that it could have been too hot for it.

If this was the case, is the ADSL flapping a likely symptom? Would anything else on the router be affected?

Indeed, is there anything I can check on the Cisco 837 to indicate whether environmental conditions are affecting it?

They have left the door on the cupboard open now so there should be more airflow but it still seems to be suffering stability issues.

Does anyone have any suggestions on how to investigate this further?

I intend to get the router replaced in case something mysterious has gone wrong with the router hardware but it will probably be a couple of days before this can be organised.

4 REPLIES
Silver

Re: checking Cisco 837 environmental conditions

General Environmental conditions apply,but no Special conditions.Possible causes could be 837 loses ADSL sync with distances larger than 3500 mts. Due to High CPU Utilization,try upgrading the IOS Software Hardware Failure.

New Member

Re: checking Cisco 837 environmental conditions

Hi, thanks for the response.

I don't think this is a distance issue as the site is only 1.8km from the exchange.

(In fact, we actually have another office further along the same street, with the exact same set-up, which is experiencing no problems!)

The router CPU is not running high and the router is not crashing or anything - the only problem is the ADSL interface flapping and whenever the router does stay connected, it syncs at very low rates.

We replaced the router with another one but the new one showed the same symptoms, which would tend to rule out a router hardware issue.

We have the same set-up at over 50 sites without issue, only this site is showing any problems!

The routers at the other sites are running the same IOS as the problem one so this doesnt seem to be a software issue either.

The telco/ISP insist there are no problems at their end and that it must be our equipment to blame. But we can see no problem with our kit, as demonstrated above.

Does anyone have any other suggestions on what we can do to try to identify the source of the problem?

Thanks.

Re: checking Cisco 837 environmental conditions

Hi there,

I've had a similar problem in the past. To rule out a hardware error, I took my laptop (duing some agreed downtime) and connected it to the ADSL via a cheap usb adsl modem. It connected at a bad rate and eventually dropped off. Proving that it wasn't the hardware on site.

My telco then did some fiddling and it came good.

HTH - if so - give it a rating

LH

New Member

Re: checking Cisco 837 environmental conditions

Thanks. The problem is now resolved - it was indeed a telco problem which they have now fixed. (Getting them to actually fix it was like pulling teeth though!)

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