ISDN PRI - No circuit/channel available

[jonesc]

I am receiving the following error message from an isdn q931 debug on an AS5300 while attempting to make an outbound call on an ISDN PRI that is configured for NFAS: Cause i = 0x82A2 - No circuit/channel available. However, I am able to make inbound calls with no problems on this circuit.

I have contacted the phone company, and they told me that the problem may be the number of digits (7 vs. 10) that I am sending them. This happens with local and long distance calls, and when dialing 7 digits or 10.

I have been working with the TAC and Verizon on this issue and have not been able to come up with a resolution. Any help would be greatly appreciated.

Here is my config:

isdn switch-type primary-ni

!

controller T1 0

framing esf

clock source line primary

linecode b8zs

pri-group timeslots 1-24 nfas_d primary nfas_int 0 nfas_group 0

!

controller T1 1

framing esf

clock source line secondary 1

linecode b8zs

pri-group timeslots 1-24 nfas_d backup nfas_int 1 nfas_group 0

!

controller T1 2

framing esf

clock source line secondary 2

linecode b8zs

pri-group timeslots 1-24 nfas_d none nfas_int 2 nfas_group 0

!

controller T1 3

framing esf

clock source line secondary 3

linecode b8zs

pri-group timeslots 1-24 nfas_d none nfas_int 3 nfas_group 0

!

interface Serial0:23

no ip address

encapsulation ppp

dialer pool-member 1

isdn switch-type primary-ni

isdn incoming-voice modem

isdn calling-number 9797796392

isdn negotiate-bchan resend-setup

no fair-queue

ppp authentication pap chap

ppp multilink

!

line 1 72

no flush-at-activation

modem InOut

transport input all

autoselect during-login

autoselect ppp

line 73 192

no flush-at-activation

line aux 0

line vty 0 4

password 7 15161958553A2E34383627

!

[tepatel]

First you need to make sure that the T1/NFAS PRI's are plugged in and configured the right order..Means nfas_int 0 to 3 should be configured and plugged in as its configured on switch.

Number of digits shouldn't matter here. Both local and long distnace call should go through (i assume that the line is provisioned for outbound calls as well in telco switch) You can see that how many digits router is sending by "debug isdn q931".

Now try removing "isdn negotiate-bchan resend-setup" and see if that helps.

That may cause channel mismatch. Pl. visit following url for more on that

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122tcr/122tdr/drfisl2.htm#1116673

Now if its still the same problem, we need to decode the channel number on which the call went out and ask telco to see status of that channel in switch.

All-n-all "circui/channel not available" is complaining about channel not available..It has nothing to do with number of digits dialed.

[makchitale]

What do we see in the isdn q931 setup? Mainly the channel id? If not mentioned we will use the desending order (ie t1 3 first then t 1 2 & so on)

Try adding this command under the lines "modem dialout controller t1 0" & see if the call goes through.

Thanks, Mak.

[zahmed]

Is the unsuccessful outbound call analog or ISDN? Although I don't see a group-async interface configured but since you have 192 MICA modems installed in this access server so I am curious to know what (analog or ISDN) you are complaining about. Pls post "debug isdn q931" for an unsuccessful outbound call for further troubleshooting.

~Zulfi

[jonesc]

I appreciate everyone's input on this issue. I have been working with the phone company and have somewhat consolidated the issue. I know that the issue only occurs when making outbound analog calls via the PRI. When I call a data-only call on the ISDN, it goes through with no problems. However, analog calls are causing me problems. Finally, I have a question for everyone. When I telnet directly to the modems that are connected to the PRI (e.g. port 2001) and make an analog call, it goes through just fine.

Thanks again,

Clint

[jonesc]

Sorry, one more thing. Here is a full ISDN Q931 debug. As you can see, the error message has changed since I have had the phone company making minor, so far unsuccessful, changes on their end.

Mar 31 07:32:01: ISDN Se0:23: TX -> SETUP pd = 8 callref = 0x004C

Mar 31 07:32:01: Bearer Capability i = 0x8890

Mar 31 07:32:01: Channel ID i = 0xE9838398

Mar 31 07:32:01: Called Party Number i = 0xC1, '7778412', Plan:ISDN, Typ

e:Subscriber(local)

Mar 31 07:32:01: ISDN Se0:23: RX <- CALL_PROC pd = 8 callref = 0x804C

Mar 31 07:32:01: Channel ID i = 0xE9838398

Mar 31 07:32:01: ISDN Se0:23: RX <- DISCONNECT pd = 8 callref = 0x804C

Mar 31 07:32:01: Cause i = 0x84C1 - Bearer capability not implemented

Mar 31 07:32:01: ISDN Se0:23: TX -> RELEASE pd = 8 callref = 0x004C

Mar 31 07:32:01: ISDN Se0:23: RX <- RELEASE_COMP pd = 8 callref = .0x804C

[tepatel]

Now the errors you are getting is different..The router receiving the call is disconnecting the call with cause "Bearer capability not implemented". That means the receiving router is not provisioned to terminate 64kbps isdn data calls (Bearer Capability i = 0x8890) originated by this router.

Visit following link for those bearer cap decoding

http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/dbook/disdn.htm#xtocid282504

So i think at this point telco have fixed the line and isdn call had forwarded all the way to the receiving router but the router receiving the call has no way to terminate that pure isdn data call. So talk to other side router admin for that.

Here is the link for troubleshooting call failures on isdn lines

http://www.cisco.com/warp/public/471/isdn_q931_ts.html