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Community Member

ISDN BRI unexpected disconnect [Solved]

Hi !

I'm new to this forum, so please redirect this post to a better suited place if wrongly posted here.

Abstract :

We try to set up a backup set of ISDN links to different branches using 2800 series routers running IOS 12.x.

One BRI goes from France to Germany and runs fine.(bri0)

Another one goes from France to Greece and has problems. (bri1).

Procedure :

We ping from France the remote in Greece  and below you will find the result of the debug isdn q931 command on the French router:

=================================================================================

Feb 26 13:59:29: %ISDN-6-LAYER2UP: Layer 2 for Interface BR1/1, TEI 91 changed to up
Feb 26 13:59:29: ISDN BR1/1: TX -> SETUP pd = 8  callref = 0x07
Feb 26 13:59:29:         Bearer Capability i = 0x8890
Feb 26 13:59:29:         Channel ID i = 0x83
Feb 26 13:59:29:         Shift to Codeset 6
Feb 26 13:59:29:         Codeset 6 IE 0x24  i = 0x80
Feb 26 13:59:29:         Called Party Number i = 0x80, 'Number to Greece branch office', Plan:Unknown, Type:Unknown
Feb 26 13:59:29:         High Layer Compat i = 0xC1FF
Feb 26 13:59:29:         Sending Complete
Feb 26 13:59:29: ISDN BR1/1: RX <- SETUP_ACK pd = 8  callref = 0x87
Feb 26 13:59:29:         Channel ID i = 0x81

Feb 26 13:59:29: ISDN BR1/1: Ux_BadMsg(): Invalid Message for call state 1, call id 0x8007, call ref 0x7, event 0xD
Feb 26 13:59:29: ISDN BR1/1: TX -> STATUS pd = 8  callref = 0x07
Feb 26 13:59:29:         Cause i = 0x87E20D - Message not compatible with call state or not implemented
Feb 26 13:59:29:         Call State i = 0x01
Feb 26 13:59:29:         Shift to Codeset 6
Feb 26 13:59:29:         Codeset 6 IE 0x24  i = 0x80

Feb 26 13:59:38: ISDN BR1/1: RX <- CALL_PROC pd = 8  callref = 0x87
Feb 26 13:59:38:         Channel ID i = 0x81
Feb 26 13:59:41: ISDN BR1/1: RX <- CONNECT pd = 8  callref = 0x87
Feb 26 13:59:41: %LINK-3-UPDOWN: Interface BRI1/1:1, changed state to up
Feb 26 13:59:41: %DIALER-6-BIND: Interface BR1/1:1 bound to profile Di200
Feb 26 13:59:41: ISDN BR1/1: RX <- INFORMATION pd = 8  callref = 0x87
Feb 26 13:59:41:         Net Specific Fac i = 0x0032332A020000
Feb 26 13:59:41: ISDN BR1/1: TX -> STATUS pd = 8  callref = 0x07
Feb 26 13:59:41:         Cause i = 0x87E27B - Message not compatible with call state or not implemented
Feb 26 13:59:41:         Call State i = 0x0A
Feb 26 13:59:41:         Shift to Codeset 6
Feb 26 13:59:41:         Codeset 6 IE 0x24  i = 0x80
Feb 26 13:59:47: %ISDN-6-CONNECT: Interface BRI1/1:1 is now connected to Number to Greece branch office
Feb 26 14:00:04: ISDN BR1/1: RX <- INFORMATION pd = 8  callref = 0x87
Feb 26 14:00:04:         Net Specific Fac i = 0x0032332A030000
Feb 26 14:00:04: ISDN BR1/1: TX -> STATUS pd = 8  callref = 0x07
Feb 26 14:00:04:         Cause i = 0x87E27B - Message not compatible with call state or not implemented
Feb 26 14:00:04:         Call State i = 0x0A
Feb 26 14:00:04:         Shift to Codeset 6
Feb 26 14:00:04:         Codeset 6 IE 0x24  i = 0x80

=================================================================================

As you can see from the date, this problem puzzle us since a long time ;-)

The Greek router debug trace show a perfect example of normal ISDN call set up. And it shows that he receive a disconect call from France and so, close cleanly the communications.

I have to add that sometimes the circuits gets up for 10 ICMP ping  packets to pass through.

The collegue which was in Greece suspected that the ISDN switchtype was not correct, so he tried all availlable switchtype values but to no avail.

I would be very gratefull if you can help us with this issue and provide us with a troubleshooting idea, or a solution !

Many thanks in advance for your help !

Georges.

8 REPLIES
Hall of Fame Super Gold

Re: ISDN BRI unexpected disconnect

Which exact IOS is France router running ?

It is generating a lot of undue status messages, possibly due to a bug. In fact, almost certainly.

Community Member

Re: ISDN BRI unexpected disconnect

Hi !

Both run ipbaseK9 IOS version 12.4-18b

Thanks for your rapid answer.

Hall of Fame Super Gold

Re: ISDN BRI unexpected disconnect

Recommend update, for example 12.4(25c).

If still troubles, take and send the trace again, include "show run int bri 1/1"

Community Member

Re: ISDN BRI unexpected disconnect

Will do that but it will take some time as someone has to go to Greece to test (don't ask why... )

I'll report back if or if not solved.

Many thanks !

It was a real PITA !

Hall of Fame Super Gold

Re: ISDN BRI unexpected disconnect

Begin with the France router, the error message must go away.

It is never necessary to travel in order to update a router. Just do it and don't tell you did.

Please remember to rate useful posts clicking on the stars below.

Community Member

Re: ISDN BRI unexpected disconnect

Hello !

So I report back having done a lot of experiments :

First,the suggested solution does not work.

We upgraded both routers tocall #461167233112.4(25c) IOS and the messages were basically the same. And of course it does not work.

What we have done :

So as these equipements are production status, we set up a mockup using a couple of 2600 we had on hand, one in France, the other one in Greece.

We used a couple unused ISDN lines and picked up the signal at the Telco acces point for the BRI.

We put on the 2600 the production config (restricted to the ISDN and dialer) and of course with the correct calling /called telephone numbers.

Using this configuration, the systems runs as described in the books, so it is perfect.

Then we moved the Greece mockup part to the room where the 2800 router is. Borowing the production IDSN line for the mockup, we were able to reproduce the behavior it should have using, of course, the correct phone number.... The trace shows a pedantic connection call set-up !

So the problem does not lie in Greece.

Then we tried the same apprach in France, moving the mockup in the same room as the 2800 production router.

If we use the line in the room where the French 2800 router is for our mockup, we get the same kind of messages I reported in first post.

So we can conclude that "there is a glitch" in the PABX transport configuration inside our site...

Now, we have to force the telecom people to admit that and compare the PABX settings for France to Greece and France to Germany... This could be the tricky part of the game :-)

Thanks a lot for your help even if it was not an exact solution it helped to isolate the problem !

Community Member

Re: ISDN BRI unexpected disconnect

Here I am again.

The line is working fine now.

The problem was that the Telco was setting a wrong set of parameter in the international call.

The Greek Telco passed them to the Cisco router which complained...

We talked with a couple of experts in this field and got the impression that a very few Telco know what to do in case of international ISDN calls set up...

So if you have a strange behavior with your ISDN links, ask them to solve their issue....

Many thanks for your help !

Hall of Fame Super Gold

Re: ISDN BRI unexpected disconnect

To be honest with you, I saw the router being wrong in first place, however good that you have resolved this.

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