Problem with ISDN on c2600.

Konstantin Dunaev · ‎02-14-2012

Hello,

I see a very strange problem with our ISDN slot on c2600 and can't somehow explain it.

If I connect a normal ISDN phone the line is working perfectly but if I connect ISDN port on our router then ISDN status shows:

#sh isdn status

Global ISDN Switchtype = basic-net3

ISDN BRI1/0 interface

dsl 0, interface ISDN Switchtype = basic-net3

Layer 1 Status:

DEACTIVATED

Layer 2 Status:

Layer 2 NOT Activated

Layer 3 Status:

0 Active Layer 3 Call(s)

Active dsl 0 CCBs = 0

The Free Channel Mask: 0x80000003

Total Allocated ISDN CCBs = 0

and I can't start a connection, I've tried with help of "isdn test call", it shows an error like "no B chanel available"

If I make an incoming call to the telephone number of that ISDN line then the status of the line changes to "MULTIPLE_FRAME_ESTABLISHED" and I can use the line just normal for Dialer connections.

After some period of time (sometime is hours, sometimes is only a minutes) the Line status goes again to "DEACTIVATED" and Dialer connection doen't work until I place an incoming call.

The ISDN Hardware is:

BRI S/T - 2186 WAN daughter card

Hardware revision 1.3 Board revision A0

Serial number 19923810 Part number 800-01833-03

FRU Part Number WIC-1B-S/T=

BRI configuration:

interface BRI1/0

description isdn-backup

no ip address

encapsulation ppp

dialer pool-member 3

isdn switch-type basic-net3

isdn point-to-point-setup

isdn outgoing display-ie

no cdp enable

router version is 2600-advipservicesk9-mz.124-2.T.bin

I can see the same problem on two different locations, where we use this type of hardware.

Please give some advise. may there is a kind of "keepalive" for BRI interfaces?

paolo bevilacqua · ‎02-17-2012

This is discussed very often.

It is normal that the line goes de-activated after a certain amount of time.

You must update IOS because what you're using is buggy, configure "isdn tei-negotiation preserve", and try again.

Konstantin Dunaev · ‎02-20-2012

Hi Paolo,

thank you for the update.

We have some other ISDN line but they stays the hole time active, may be they went in "deactivate" status sometimes but at least comes online again without problem. But in these cases I can them "wake up" only if I try to call the number on those ISDN linens.

Do you mean that a IOS update should solve our problem?

paolo bevilacqua · ‎02-20-2012

As indicated above. Update IOS.

Konstantin Dunaev · ‎02-23-2012

Hi Paolo,

I've updated the IOS to c2600-entservicesk9-mz.124-15.T14.bin but the problem is exactly the same.

You said that is "normal" if the line goes de-activated after a certain amount of time, but how can the router re-activate the line again?

We used ealier the cisco 1800 with the same ISDN connection without any problem over a year, and the problem first arised after we replaced it to c2600.

paolo bevilacqua · ‎02-26-2012

Please configure "isnd tei-negotiation preserve" if still problems, post "debug bri" when line is de-activate and you try an outgoing calls.

lgijssel · ‎02-17-2012

Such strange behavior can be caused by improper grounding.

Please verify that the router is properly grounded to the same ground as the ISDN lines.

regards,

Leo

Konstantin Dunaev · ‎02-23-2012

Hi Leo,

I don't really believe that grounding can cause such a strange behavior, but we can try.

The question is how can I "connect" the cisco to the same ground as ISDN line? I mean we get ISDN line from outside and I have no idea how and where it's grounded. Or is it enough just to graound our cisco to a normal house ground?

lgijssel · ‎02-24-2012

Hi Konstantin,

There was a time when I also considered this unlikely but after I saw a troublesome installation working when it was connected to an improvised ground circuit I took a lesson out of it. Racks are normally grounded also but perhaps not in your case; you never know. Anyway, your ISDN router has the option to attach a special grounding clamp:

http://www.cisco.com/en/US/docs/routers/access/2600/hardware/installation/guide/2600ch3.html#wp1057120

Connect this to the ground circuit in your server room and check if it resolves your problem.

regards,

Leo

zoltanszasz · ‎03-04-2012

Telcos power up the lines so it is their interest to break up connection if lines not in use.

Try dialer persistent on the dialer interface and tell us if it helps. It's just a guess, but maybe solves problem.

Konstantin Dunaev · ‎03-05-2012

Hi Zoltan,

with power saving would be all OK, but how can end-device use then the ISDN line if it were power-off? As I said I can't bring the line UP fron the Cisco side.

zoltanszasz · ‎03-05-2012

So i read around more on this, very interesting situation and few people kinda have same issue.

1. Check switch type with provider

2. Some providers don't bring the line up without SPID's

3. If you make up an rj45 loopback plug(pin 1> pin5 and pin 2> pin 4)then plug this into you BRI INTERFACE it should bring your interface up then do an isdn statusto see if layer 1 and 2 stay up.

Here is a preety good url for "troubleshooting LAYER 1 on isdn bri line"

http://www.cisco.com/warp/public/129/bri-layer1.html

for layer 2 pl. visit

http://www.cisco.com/warp/public/129/bri-layer2.html

ISDN line provisioning: http://www.cisco.com/en/US/docs/routers/access/800/801/software/configuration/guide/provisio.pdf

zoltanszasz · ‎03-11-2012

taken care?

Konstantin Dunaev · ‎03-12-2012

Hi,

thank you for the info, I've tried different things but without result.

The funny thing is following, we have 2 sites, one of them (SiteA) is connected directly to Telco port, the second (SiteB) is connected to local PBX port.

With Telco port I've got the stable link only after I've staticly configured TE to "0", auto TE and all other values don't bring the inteface UP.

With PBX port is working strange as well - during the port in " MULTIPLE_FRAME_ESTABLISHED " I can place a call, but only a single one, after the call terminates port goes to status "TEI_UNASSIGNED" and stays until I manulaly reset the BRI interface, after the reset the line goes back to normal "MULTIPLE_FRAME_ESTABLISHED " and stays there until port gets "DEACTIVATED" status.

paolo bevilacqua · ‎03-12-2012

You can have a problem with 2600 obsolete hardware. As you noted in you first message, a 1800 works fine with the same config.