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T1 PRI Errors

Good Afternoon,

I'm trying to get a T1 PRI online at a new site. They have confirmed framing, line coding and I believe my config is good. I've done these before with no issues (or maybe a cable). But on this occasion i'm seeing a large amount of Line code violations, and doing a q921 debug, I see SABME from our router to the telco (multiple) and then a response, sometimes a SABME back, though every so often to the conroller will go down, and then back up. Eventually transitioning to frames_established..                 

e.g.:

Jul 22 20:20:18.425: ISDN Se0/1/0:23 Q921: L2_EstablishDataLink: sending SABME

Jul 22 20:20:18.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:19.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 15:20:20.413: %LINK-3-UPDOWN: Interface Serial0/1/0:23, changed state to up

Jul 22 20:20:20.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:21.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:27.425: ISDN Se0/1/0:23 Q921: L2_EstablishDataLink: sending SABME

Jul 22 20:20:27.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:28.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:29.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:30.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:36.425: ISDN Se0/1/0:23 Q921: L2_EstablishDataLink: sending SABME

Jul 22 20:20:36.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:37.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:38.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:39.085: ISDN Se0/1/0:23 Q921: User RX <- SABMEp sapi=0 tei=0

Jul 22 20:20:39.085: ISDN Se0/1/0:23 Q921: User TX -> UAf sapi=0 tei=0

Jul 22 20:20:39.425: ISDN Se0/1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0

Jul 22 20:20:41.749: ISDN Se0/1/0:23 Q921: User RX <- RRp sapi=0 tei=0 nr=0

Jul 22 15:20:42.413: %CONTROLLER-5-UPDOWN: Controller T1 0/1/0, changed state to down (LOF detected)

Jul 22 15:20:42.417: %MARS_NETCLK-3-CLK_TRANS: Network clock source transitioned from priority 1 to priority 10

Jul 22 15:20:44.413: %LINK-3-UPDOWN: Interface Serial0/1/0:23, changed state to down

T1 0/1/0 is up.

  Applique type is Channelized T1

  Cablelength is long 0db

  No alarms detected.

  alarm-trigger is not set

  Soaking time: 3, Clearance time: 10

  AIS State:Clear  LOS State:Clear  LOF State:Clear

  Version info FPGA Rev: 08121917, FPGA Type: PRK1

  Framing is ESF, Line Code is B8ZS, Clock Source is Line.

  CRC Threshold is 320. Reported from firmware  is 320.

  Data in current interval (528 seconds elapsed):

     748499 Line Code Violations, 25991 Path Code Violations

     144 Slip Secs, 416 Fr Loss Secs, 199 Line Err Secs, 0 Degraded Mins

     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 528 Unavail Secs

  Data in Interval 1:

     1662963 Line Code Violations, 158884 Path Code Violations

     25 Slip Secs, 303 Fr Loss Secs, 811 Line Err Secs, 1 Degraded Mins

     319 Errored Secs, 245 Bursty Err Secs, 64 Severely Err Secs, 595 Unavail Secs

  Data in Interval 2:

     2361014 Line Code Violations, 224899 Path Code Violations

     10 Slip Secs, 244 Fr Loss Secs, 875 Line Err Secs, 0 Degraded Mins

     596 Errored Secs, 360 Bursty Err Secs, 226 Severely Err Secs, 294 Unavail Secs

any ideas? we've changed our cable and card and when I do a soft loopback (loopback diag under controller config) I get no errors and the badframe message on the q921 debug. Telco says their end is good.

1 ACCEPTED SOLUTION

Accepted Solutions

Re: T1 PRI Errors

Is this a VWIC3 by any chance?

VWIC3 are so much sensible to cabling or L1 issues then VWIC2, that will expalin the tons of Line/Path code violations if you already tried replacing the wiring.

What device is the far end? Is a PBX? or a service provider equipment? We should also confirm if the upstream device is a Network or User side, so we can fix the Slip Sec errors.

In order to confirm that this is not a faulty card or not, you can do a back to back connection between 2 routers, setting one as network and the other one as user, and configuring then to be the clock source and the other to receive the clock respectively. In addition, try a hardware loopback test, if there are no Line/Path code violations, the problem is definitively the other end.

HTH

--
Jorge Armijo

Please remember to rate helpful responses and identify helpful or correct answers.

-- Jorge Armijo Please remember to rate helpful responses and identify helpful or correct answers.
27 REPLIES
Hall of Fame Super Silver

T1 PRI Errors

Do you have clocking setup properly?

Can you post "sh network-clocks"?

Chris

New Member

Re: T1 PRI Errors

I believe so, my config is:

network-clock-participate wic 1

network-clock-select 1 T1 0/1/0

controller T1 0/1/0

cablelength long 0db

pri-group timeslots 1-12,24

and the show network-clocks returns 'Good' when the link is up. It almost seems from the q921 above that our router is sending the SAMBE requests, getting nothing in return (provider not responding), they send a SAMBE, our 2911 responds (UA) then gets nothing, tries again,doesn't get a correct response then LOF.

Re: T1 PRI Errors

Is this a VWIC3 by any chance?

VWIC3 are so much sensible to cabling or L1 issues then VWIC2, that will expalin the tons of Line/Path code violations if you already tried replacing the wiring.

What device is the far end? Is a PBX? or a service provider equipment? We should also confirm if the upstream device is a Network or User side, so we can fix the Slip Sec errors.

In order to confirm that this is not a faulty card or not, you can do a back to back connection between 2 routers, setting one as network and the other one as user, and configuring then to be the clock source and the other to receive the clock respectively. In addition, try a hardware loopback test, if there are no Line/Path code violations, the problem is definitively the other end.

HTH

--
Jorge Armijo

Please remember to rate helpful responses and identify helpful or correct answers.

-- Jorge Armijo Please remember to rate helpful responses and identify helpful or correct answers.
VIP Purple

Re: T1 PRI Errors

Hi,

If it is a  Service Provider at other end, can u try doing physical loop of pairs and ask them to check with BERT which would help in checking the media.

After this, u can try giving remote loop from VWIC card towards SP, which would check the T1 config and card as well.

regds,

aman

New Member

Re: T1 PRI Errors

They have tested to the smart jack and to the end of the cable that we are using to connect to our equipment. The say its clean. When we unplug from the smartjack and put a physical loop on the end of the cable we're using I get no errors and it's all clean. Basically this only happens when we're connected together.

The card is a VWIC3-1MFT-T1/E1. We have replaced the router and card (persons on site aren't network guys, so easier to just send them new package).

Provider is sending a tech tomorrow, but i'm not confident it will get resolved.

VIP Purple

Re: T1 PRI Errors

Hi ,

Just a thought, can u also check the earthing at site.

regds,

aman

New Member

Re: T1 PRI Errors

of the line? equipment? I'll get someone to check.

VIP Purple

Re: T1 PRI Errors

Hi,

You need to check the voltage levels on Electric Wires.You can ask the Site Electrician to check.

Why I was thinking so since problem comes when T1 is terminated on Router ?

regds,

aman

New Member

Re: T1 PRI Errors

Just to comment on the VIC3 card being more susceptible to errors; does this mean that we cant use Cisco equipment to terminate PRIs anymore? The provider has their demarc and we're plugged right into it. We use this card and router combination elsewhere.. just curious what others have done in this situation. Checking our voltage on our wiring is maybe possible, but it's all the provider's wiring.

The other side is set to network. I also changed ours to network but that didn't make a difference.

thanks.

Green

T1 PRI Errors

Hi,

Looking at this link for T1 troubleshooting.

http://www.cisco.com/en/US/partner/tech/tk713/tk628/technologies_tech_note09186a00800a754a.shtml

You are seeing SABME alerts

Check you have the correct ISDN switch type

Regards,
Alex.
Please rate useful posts.

Regards, Alex. Please rate useful posts.
New Member

Re: T1 PRI Errors

thanks Alex.  switch-type confirmed as NI2. I don't have access to that link, but if it's the layer1 troubleshooting for LOS or LOF, i've been through it (checking framing, etc).

New Member

im a beginner in voice can

im a beginner in voice can you please explain how to do this method?

:"In order to confirm that this is not a faulty card or not, you can do a back to back connection between 2 routers, setting one as network and the other one as user, and configuring then to be the clock source and the other to receive the clock respectively. In addition, try a hardware loopback test, if there are no Line/Path code violations, the problem is definitively the other end."

Hi,

Hi,

The following links should help

http://www.cisco.com/c/en/us/support/docs/wan/t1-e1-t3-e3/9333-t1-back-to-back.html

https://supportforums.cisco.com/discussion/9854236/pri-config-back-back

HTH

Manish

New Member

Re: T1 PRI Errors

here's the network clocks just for kicks..

Network Clock Configuration
  ---------------------------
  Priority      Clock Source    Clock State     Clock Type

     1          T1 0/1/0        GOOD            T1
    10          Backplane       GOOD            PLL

  Current Primary Clock Source
  ---------------------------
  Priority      Clock Source    Clock State     Clock Type

     1          T1 0/1/0        GOOD            T1

      

any every played around with the 'cablelength' command? I've always left it at default.. (long 0)

New Member

Re: T1 PRI Errors

Telco arrived and did testing, everything checks out on their end.      

Re: T1 PRI Errors

That's the only thing I would think about:

http://www.cisco.com/en/US/docs/ios/12_2/dial/configuration/guide/dafntpri.pdf

http://www.cisco.com/en/US/docs/ios/dial/configuration/guide/dia_cfg_ntwk_isdn_pri_ps6441_TSD_Products_Configuration_Guide_Chapter.html

Service Provider usually is Network and Customer equipment is User.

--
Jorge Armijo

Please remember to rate helpful responses and identify helpful or correct answers.

-- Jorge Armijo Please remember to rate helpful responses and identify helpful or correct answers.
Hall of Fame Super Gold

Re: T1 PRI Errors

a.brazendale wrote:

Telco arrived and did testing, everything checks out on their end.      

That is normal. The circuit is fautly, but they refuse to admit that. Ask them to place and received call using their own test equipement, on your premises with someone seeing it. Then the penny will drop.

New Member

Re: T1 PRI Errors

They've left now unfortunately. They ran the circuit clean with no errors for 30 minutes. As soon as we plug our end in, we see incrementing violations. I'm trying to get a VWIC2 card and 2800 to see if that makes any difference, i've heard of people seeing issues with 2911s.

Re: T1 PRI Errors

You don't need to replace the whole router, just by using a VWIC2 you'll see that the circuit will come up... As I metioned, VWIC3 are incredibly sensible to Line/Path code violations, and I have tested, If I connect 2 routers back-to-back with VWIC3, they work just fine... Usually the problem is the TELCO device/connector/card whatever, they just don't accept it's their fault...

--
Jorge Armijo

Please remember to rate helpful responses and identify helpful or correct answers.

-- Jorge Armijo Please remember to rate helpful responses and identify helpful or correct answers.
New Member

Re: T1 PRI Errors

thanks. We actually put another VWIC3 card in slot 0/0/0 and the circuit came up clean. I was able to make/recieve calls and everything. Left it running for a hour with a call open, no issues. Controller shut/no shut, no issues.. rebooted the router, back to square one, severe line code violations and flapping layer1.

i've ordered a VWIC2 card and it should be at site tomorrow. I will post back..

New Member

Re: T1 PRI Errors

Hi Guys, sorry for the late reply. I swapped out the card for a VWIC2 and the PRI came up with no issues.

thanks for all your help.

Hall of Fame Super Gold

T1 PRI Errors

a.brazendale wrote:

Hi Guys, sorry for the late reply. I swapped out the card for a VWIC2 and the PRI came up with no issues.

thanks for all your help.

That is a serious issue and Cisco should investigate why that happens. But I guess they will not.

New Member

Re: T1 PRI Errors

Just went through this same scenario.  Did the whole dance with the carrier (they tested end to end, ran clean of course, threatened them etc. ). Tried on two different 3925e's with a VWIC3-4MFT in both.  Then a VWIC3-2MFT with the same result.  Tried a VWIC2-1MFT, and it came up perfectly.

Got TAC on the phone, guy found the bug (CSCua50697), said it was fixed in the verison i was running (15.2.M4 or something), we upgraded to 15.3.M3 with the same results. 

Long story short, there IS a work around.  Put this command under your controller: hwic_t1e1 equalize

It's a hidden command they put in there just for this problem.

VIP Purple

Re: T1 PRI Errors

Hi Richard,

thanks for sharing the info and resolution[+5]

finally , your router is running on which IOS version .If possible, can u share the show version,show diag  and show config.

regds,

aman

New Member

Re: T1 PRI Errors

Sure, this is for my production router, i just set the commands in there and it came up perfectly.

VIP Purple

Re: T1 PRI Errors

Richard, thanks a lot.

regds,

aman

New Member

I had the same problem with a

I had the same problem with a VWIC3-2MFT-E1/T1.
was solved with hwic t1 e1 equalize command.

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