Disconnection problem with a 725 router

[TotalRock]

We have a set up with a 725 router connected to a Bulldog comms SDSL line that we use to broadcast a live Radio show. Ever since it was set up we have been experienceing disconnections every 50 ish minutes. The disconnections usually only last for a moment. Occasionally we have to manually reconnect the line.

Bulldog and Solwise support are looking into and it seems to be an issue with sync between the router and the ISP being dropped momentarily. It consistantly happens every 50/51 minutes tho.

I just wondered if anyone else had experienced anything like this.

Digi
Totalrock Radio

[DazTilt]

I had a problem like that a few weeks back with one of our circuits. It was down to whats called a "high open".

This is when the resistance on the line increases because of water or moisture in a cable join or MDF.

BT ended up switching to another pair in a trunk to the exchange due to flooding in a cabinet.

It would sync up run for a while, then drop, sync and then drop.

Started to become more apparent when the wether got more cold and wet. Then when sun comes out it would stay sync'ed for a little longer.

Can also be down to loop length, but BT should have made sure they covered that base :-).

Have you got any logs from router showing logs, also please post the line info.
The router you are use has a command in the CLI to show line details such as attenuation db, and SNR etc.

This would help show a line fault, take a few samples and post them.

Also check with ISP you login and line settings are correct.

[TotalRock]

The performance stats of the router are pretty steady - as below

--> dsl show perf
Noise Margin : 37 dB
Attenuation : 10 dB
Receiver Gain : 61 dB
Output Power : 13 dBm

[DazTilt]

If you keep checking the line stats for say 10min do any of the values change much ?

Do you have a directly wired SDSL point in the building stright from BT's MDF or does it go through any extension, private MDF's.

One cause could also be cross talk from another line etc.

If there is any private wiring between you and the bt part of the line are you able to connect the sdsl router closer to the entry of the circuit into your building. (Internal Building wiring can be a pain as BT do not support it with out charging :-( ).

Do you no how far you are from the local exchange.

please try and monitor line stats for a while, if you are lucky you may see something just before it drops sync.

[TotalRock]

I dont feel that wiring is the problem as the drop out happens every 50 mins or so and only for a second. We feel its more of a clocking issue.

The line stats are pretty much solid and dont change that much.

The Exchange is within 1 mile of our location as its int he west end of London! Busy I know, but I doubt its that.

The logs fromteh router dont reveal anything obvious either.

We are getting a replacement router to swap out hopefully today. Once thats swapped out, we will monitor it and ill let you all know what we discover.

[Louise]

FYI

The replacement router I've sent to TotalRock was one of the units actually tested by DazTilt so we know that one is fine! :-)

[TotalRock]

Look forward to it!

[DazTilt]

I need some more info to help figure out your problem.

1. When you lose your link, does the routers sync line light go out and then you see it re-train?

2. What are you using to tell when you are off line, such as pinging an external host constantly ?

3. Does the ISP report you DSLAM port as going up and down ?, our kit notifies us of link loss by syslogs and alarms, does the isp have any logs to collate with the times you are losing your link.


We have tryed these with a few SDSL lines and they work well, the chipset used works will with most of the DSLAM kit we tried including Alcatel and Globespan.

We have also tried them back to back over good long copper circuits to see how well they work with noise and cross talk from other services such as ADSL etc and not really ever had a problem, apart from line related ones like cross talk and high resistance loops.

It could ba at another level you are lossing your link, maybe at the ATM PVC stage / Backhaul etc. I need a bit more info to come up with a fix.

Please post what you have tried so far and any other info and I will do some more digging.