sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Timing Issue?

Hey folks,

I have been experiencing some issues with a point-to-point T-1 that carries voice and data between 2 offices. It seems that under stress I'm losing packets. I have not heard of any issues on the voice side, though that doesn't necessarily mean its not an issue. I am waiting on Verizon to do some stress testing tonight to see what that tells me, but the tech I spoke with did mention that he some some slippage on the line, and that I should check timing on my device.

The equipment is in a remote office, so I don't have physical access to the device, which is an Adtran TSU120. I did not do the initial setup for this site and I have no idea who installed the equipment. Read: I may be moving to the 'Request an Installer' forum to see if I can find someone to work on this for me.

I really just want to know if the LEC is correct that timing might be suspect in this case, which is apparently being provided by the CPE. Also, if anyone has worked on this model TSU before, can it be accessed remotely?

Timing errors would cause issues with your data that may not show up on the voice side. As far as the CPE I am not familiar with it sorry.

Thanks Antonthy.

Thanks Anthony.

Generally the TSU 120 is not accessible via remote without some special initial setup. Virtually every time I have a similar issue, its a carrier problem.
Mike

Thanks mforrence, my experience has been the same. Usually, though, I can providing CSU error stats to prove my case as we use mostly Cisco routers with plugin CSU cards. No such luck in this case.

Incidentally, the carrier ran a 30 minute stress test last night and said that they saw no errors to the CSU on either end of the circuit. The circuit is running ok now, but I suspect I be revisiting this issue shortly. Of course I have had circuits magically fix themselves after requesting the carrier run tests.

If your LEC is worth a hoot they can put up a monitor to see if they get intermitten errors. For slips they would have to time their test set off a known timing source, unless they have remote test access which does this anyhow. I assume from your post that your CSU doesn't have an error report.

Unfortunately, I am not able to see the CSU. The router attached is an older Rad WebRanger II, which I can access, though I'm not too familiar with the device. I did have a spare here and managed to swapped out the original for testing, but just by copying settings to a new device.

The LEC is Verizon in our case, and I have been through this with them a bunch of times on other circuits. My experience has been that it is almost always a LEC issue. I would gladly pay Verizon in this case to prove me wrong. I would hate to make a 250+ mile trip to prove equipment ISN'T the issue.

That said, I'm certainly uncomfortable with the current situation, not being able to look into the Adtran.

I did download a manual for this device and will be reading up on it shortly.

In case anyone is interested...

The problem turned out to be related to power, not to a LEC issue or equipment failure/misconfiguration. Looks like the power outlet to which the router was connected had been flaking out. This was causing the router to reset itself every so often. I have not called in an electrician yet to check the circuit, which I'm thinking is overloaded to some degree. I had someone in the office connect the equipment to another nerby outlet and all has been fine for some time now.

The thing that made this hard to trouble-shoot was that while the router was not showing any error frames, the Verizon tech said he saw some frame slippage in his testing. I figured it must be a configuration issue with timing or some such.

I finally figured out that the routers stats were resetting each time we had the problem. That would only happen when there's a power reset to the equipment. Also, someone in the office mentioned that this seemed to happen when they sent jobs to a printer, which I'm guessing is on the same circuit.

Sure took me a long time to come to figure this out.
:bang:

On the up side, I was able to trouble-shoot this one without having to make a trip up to NYC, where the remote office is located.

Thank you for taking the time to let us know what resolved the issue.