sundance-communications.com/forum Forums VOIP Phones & IP PBX Networking Point-to-Point T1 Down

Some questions here...I'm really trying to get my head wrapped around understanding this, so bear with me...

Have a remote site, they have a T1 ckt that eventually comes into a VPN cloud on our side. This cloud terminates over a 3MB pipe to our NOC.

Originally it was showing up/dwn on the Ser int that connects to the providers side. This is a cisco 2600 rtr w/WIC. I was able to get them to enable loop back on it, but couldn't do much more testing. Took it out of loopback, briefly went to up/up then back to up/dwn. Called telco, had them test again, they said they looped the smartjack and tested fine. Verified they had taken the loop out and ckt should be up. NOW, it is dwn/dwn. Along with that, DCD=down DSR=up DTR=up RTS=up CTS=down. Not getting any errors.
When I had up/dwn DCD & CTS were up. Also, a couple times did notice a bunch of input errors/CRC's, but not sure if that was from their testing...?

ALSO in here, all along the CD(carrier detect) LED has been solid green on the cisco WIC. After the last time had telco test ckt and it went dwn/dwn, I now have same thing w/CD and AL(alarm) LED is yellow.

Changed encapsulation, speed, clock etc. are automatic, tried shutdown interface and bring back up, reboots...Nothing.

AT&T is provider they said they looped the SJ and tested fine. To dispatch of course we get charged if they find no problem. I'm having them dispatch as I don't know what else to check. They said 'the local telco is going onsite, AT&T is going to "clear the demarc" and the telco will do head-to-head testing while keeping the ckt down'.

Any ideas of anything I might have missed here? Any better steps I should have taken? Please help me decipher the meaning of this here...AT&T looped the SJ, they basically setup a ckt from their CO to the side of the building where the T1 comes into and were able to send signal to/fro...? Now what do they mean by 'clear the demarc'? And 'head-to-head' testing?

Trying to envision this entire process...First AT&T's CO is where it starts...AT&T CO-->DS3 or other-->local telco provider switching station(exact terminology??)-->local loop (T1) to demarc at building-->demarc to SJ-->SJ to our router...

I've heard that "testing clean to the smartjack" line more times than I can count. Usually (95+% of the time) it's a carrier issue. I'd have them dispatch as even if they find it to be customer equipment, the cost to verify this is less than the frustration and lost productivity of having a site down.

The only other things you could try is replacing cables/equipment if you have spares.

I believe the head-to-head testing is them plugging in a testing device (like a tberd) to the smart jack to test signal from the office. Perhaps others more qualified can elaborate on that testing.

First I am not sure what kind of a WIC you have. If you have a WIC-DSU-T1 plug a hard loop into it (with the encapsulation set to HDLC) and see if the thing come up. Next unplug the RJ48 from the smartjack and and plug the loopback in there. Effectively this tests all of the CPE cabling. You should get up/up. What type of circuit is this P-to-P, Frame, MPLS or what? From you description it sounds like MPLS but if it is a P-to-P you could also loop from the far end. Depending on the WIC you can issue commands to the CSU to send a loop remote or loop local.

The WIC is internal Cisco WIC. It's WIC-->SmartJack. P-to-P ckt. Unfortunately do not have access to smartjack, also not really able to do much loopback troubleshooting.

Other than LED indicators and what I can see on the cisco...That's why I'm trying to really get an understanding of this from the telco side...Being limited w/the troubleshooting I can do on our side, it would help to be able to sift through the telco side a little better so I am not dispatching them if the issue is on our side.

There is a MFT WIC and a WIC-T1 both have different procedures to loop. One uses a service-module command and the other is done in the interface controller. If it is a P-to-P you can loop the side by you and the circuit will come up.

I hate to be the bearer of bad tidings, but your carrier isn't going to care what your equipment beyond the smart jack is doing and most likely isn't going to understand your terminology, if that's the way your reporting it.

If the T-1 is good what you're paying for the dispatch you could put a CSU on each end of the circuit with PM capabilities, then now and in the future you'd know if you have a T-1 problem or not. If you have a CSU on this what's it telling you?

I guess I don't understand. Both of the WICs we are talking about have integrated CSU/DSUs. Even if you did not use an MFT or a WIC-T1-CSUDSU-V1 you would have to use a WIC-1T or WIC-2T and then you would still need an external CSU/DSU. I all cases you are using a CSU/DSU. Am I missing something?

So if you have a CSU what is it telling you the line is doing? Forget all the other stuff, what is the T-1 PM data telling you?

Sorry for jumping in so late, but I just got back to town.

"Head to Head" testing means running from a test set at one end to a test set at the other end (as opposed to running to a loop).

HtH will often pick up errors that loop testing won't. We only used it on real nasty troubles.

Sam

Hey Sam, welcome back. What I'm trying to do and not too well evidently, is explain to look at this in different pieces. What's the T-1 telling them, verses looking at everything overall. Find out where the trouble is first, then fix the piece that's bad. Also to use circuit terminology when reporting this to the supplier instead of Cisco or IT lingo. This will help get the problem resolved much quicker.

When I researched the WIC (which I had no idea what that was until I did) I found that depending on which version they have PM monitoring capabilities are available on the T-1. So my point there was if the built in CSU has this ability, use it. Also depending on version they have the ability to run head to head with the CSU. Looks like the tools may be there.