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Webcast-Catalyst9k
New Member

Router still show ISDN Active even when ISDN is down!!

Hi experts,

I encounter a situation where my router still showing the isdn is up (in "sh isdn ac" command) even when the ISDN is down (I shut it down). Is it an IOS bug?

My router is Cisco 3640 with IOS Version 12.3(21). The IOS are currently upgrade from Version 12.2(6a).

Thanks.

Azmir.

8 REPLIES
Silver

Re: Router still show ISDN Active even when ISDN is down!!

Hi Azmir ,

Can you paste the config of the router ..

Thanks,

satish

New Member

Re: Router still show ISDN Active even when ISDN is down!!

Hi satish,

Is the config necassary? I don't think it is due to configuration. Thanks.

Azmir.

Silver

Re: Router still show ISDN Active even when ISDN is down!!

Hi Azmir ,

Is it possible to paste show isdn active , sh isdn history and sh isdn status outputs.

and sh run int bri

Hall of Fame Super Gold

Re: Router still show ISDN Active even when ISDN is down!!

Azmir

The information that Satish is asking for will help us to understand what is happening. I wonder if what you are describing is on the bearer channels that transmit data or is on the diagnostic and signaling channel which is always up and active in ISDN (it is how your router and the ISDN switch keep in sync with each other and how the switch would signal an incoming call - it is normal for this to be active all the time).

HTH

Rick

New Member

Re: Router still show ISDN Active even when ISDN is down!!

Hi all,

Thanks 4 your responds. I have attached the all info required. Thanks.

Azmir.

Hall of Fame Super Gold

Re: Router still show ISDN Active even when ISDN is down!!

Azmir

I do not see a problem in what you posted. The show isdn status clearly shows that the signaling channel is active but that there are no active calls in progress.

The show interface bri0 show as up but this is showing the signaling channel. If you do show interface bri0:1 or bri0:2 which are the data channels they should show as down.

At worst I think what you posted shows some confusion about show isdn active. It shows 6 calls. I do not see how that can possibly be accurate with one BRI interface. Is there possibly anything else on that router doing ISDN or any other kind of PPP? Or I wonder if it is showing calls that have been active not necessarily those that are currently active.

HTH

Rick

New Member

Re: Router still show ISDN Active even when ISDN is down!!

Hi Rick,

The ISDN are only used as backup to Leased Line. First the ISDN will dial to nearest node of provider MPLS cloud, if failed it will dial direct to HQ.

So far there is no problem at this site. But I really concern about the output of the sh isdn ac command, it will hard for me to troubleshoot next time,especially regarding the time of the ISDN have been dial.

Regards,

Azmir.

New Member

Re: Router still show ISDN Active even when ISDN is down!!

Try on the Serial int/subint. to have this config:

Backup int Bri 0/0

Backup delay 30 120

That will put the Bri in a"standby" mode. hope taht help.

thx.

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