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Toubleshooting ISDN issue

Hardware: 1604

Problem: No data passing on Bri 0

Background: This line is nailed up 24X7 and has been rock solid for a couple of years. Two days ago, it suddenly stopped working.

Attempted corrective action: Went on site and rebooted. Did shut/no shut on interface. Verified that the running configuration hadn't changed. Did a "sh int bri 0" Results as follows: Bri 0 up, up. Bri 0:1 down, down, Bri 0:2 down, down. The green NT 1 lamp does not light. Replaced the patch cord going from the router to the extended Dmarc jack. Still totally unresponsive. Did a "Sh isdn status" which told me that layer 1 was activating, layer 2 was down, and that my Spids weren't valid. At this point I opened a trouble ticket with the telco.

The telco's tech came out this morning, insists that the line tests fine to the Dmarc. I ask if he would please test the extended Dmarc, which he agrees to do. He says it tests fine again, I ask if he would please test all the way through my patch cord to eliminate any possibility of it being a wire issue. He plugs my patch cord into his testing equipment, and it doesn't light any of his test lamps. He concludes that it is a bad patch cord (even though it's brand new and I tested it before installing it) and says he will put one of his own on there. He uses one of his, and it takes a *very* long time to light his test lamps, but they do light, so he insists it is our problem. I ask him if there is any possibility that the line might have been re-provisioned because my hardware reports my spids to be invalid. So he does a spid test. The spids come back exactly as I have them in the router, but spid2 says "in use" on his test equipment. He then does something and gets a dial tone on it. He tells me he doesn't know why it says in use, but that he has dial tone off of both channels so they must be good. He runs the spid discovery check several more times from the Dmarc, the extended Dmarc, and through the patch cord, and the second channel always comes up "in use" but he is always able to get dial tone off of them, and they always test clean from the CO. Below are the results of my "sh isdn status"

wces#sh isdn status

The current ISDN Switchtype = basic-ni1

ISDN BRI0 interface

Layer 1 Status:


Layer 2 Status:


Spid Status:

TEI Not Assigned, ces = 1, state = 3(await establishment)

spid1 configured, spid1 NOT sent, spid1 NOT valid

TEI Not Assigned, ces = 2, state = 1(terminal down)

spid2 configured, spid2 NOT sent, spid2 NOT valid

Layer 3 Status:

0 Active Layer 3 Call(s)

Activated dsl 0 CCBs = 2

CCB:callid=0, sapi=0, ces=1, B-chan=0

CCB:callid=8017, sapi=0, ces=1, B-chan=0

Total Allocated ISDN CCBs = 2

I am quite confused as to why it would say my spids are neither valid nor sent, and why does channel 2 say "terminal down"

Any ideas?



Re: Toubleshooting ISDN issue

Try clearing the BRI interface, with "clear int bri 0/0" a few times.

What is the IOS version used ?

Can u check "show isdn status" a few more times to see, if the CCBs allocated are increasing ?

The problem could still lie with the provider. I have seen very similar situations where the fault was at the provider side, but they insist the fault is with our equipment.

Try asking the provider to reset/reinitialize the spids for your circuit.

Cisco Employee

Re: Toubleshooting ISDN issue

First of all use "clear interface bri0" and see atleast layer comes to "ACTIVE".

Anyway, does layer every get to "ACTIVE" at all? If not then you need to tart troubleshooting from layer 1 and up. Here is the urls for layer 1 troubleshooting

Once the Layer 1 is active, As you can see that the router reports SPID'd invalid, so something is wrong there about those spid numbers. Here is the link which will help you Troubleshooting invalid spid's

For layer 2 not getting to "multiple_freame_established" state, visit

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