Requested circuit/channel not available

[vedran_srsen]

Hello,

I have a problem with a PRI link. We have installed CCM 3.3(3) and a 3745 with a PRI link to the telco. The 3745 is configured as a MGCP gateway. When I try to initiate an outbound call, I get the following Q931 debug message:

*Mar 1 01:47:14.967: ISDN Se3/0:15 Q931: TX -> SETUP pd = 8 callref = 0x0005

Bearer Capability i = 0x8090A3

Standard = CCITT

Transer Capability = Speech

Transfer Mode = Circuit

Transfer Rate = 64 kbit/s

Channel ID i = 0xA9839F

Exclusive, Channel 31

Calling Party Number i = 0x0081, 'XXXXXXX'

Plan:Unknown, Type:Unknown

Called Party Number i = 0x80, 'XXXXXXXXXX'

Plan:Unknown, Type:Unknown

*Mar 1 01:47:15.127: ISDN Se3/0:15 Q931: RX <- RELEASE_COMP pd = 8 callref = 0x8005

Cause i = 0x82AC - Requested circuit/channel not available

When I try an inbound call I get a busy signal, and a similar debug message (if I use another router to initiate that ISDN call).

This is the "show ISDN state" screen:

ISDN Serial3/0:15 interface

dsl 0, interface ISDN Switchtype = primary-net5

L2 Protocol = Q.921 L3 Protocol(s) = CCM-MANAGER

Layer 1 Status:

ACTIVE

Layer 2 Status:

TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED

Layer 3 Status:

0 Active Layer 3 Call(s)

Active dsl 0 CCBs = 0

The Free Channel Mask: 0xFFFF7FFF

Number of L2 Discards = 1, L2 Session ID = 13

So I presume there is nothing wrong with the signalization??

I contacted the telco person, and he told be that he sees some kind of BLOCKING state on our side of the PRI link.

Please help or give at least some guidelines what to try next!

Thanks in advance...

[aamercado]

Looks like your getting a message back from the PSTN that the Channel31 is not available hence the Call Cannot complete.

Are you using a full E1 to the PSTN channels 1-31 and has the Telco provisioned the lines for calls in both directions? Maybe also confirm with telco whether it is top/down or bottomup?

You can also check if there is a b-channel locked on the Telco side you can unlock by unchecking "Inhibit restarts at PRI initialization" on the CCM gateway configuration page. After changes, you may need to reset the gw and/or restart the router.

[vedran_srsen]

Thanks a lot, this was a really helpful hint ("Inhibit restarts at PRI initialization"), although it didn't work at first. I unchecked this option, clicked update, reset the gateway and reloaded the router, but it still didn't work. So I deleted the gateway from CCM and took off all of the mgcp and ccm configuration from router, reloaded and repeated the procedure of creating the gateway but this time with "Inhibit restarts at PRI initialization" option unchecked before clicking Insert. And then it worked.

Once more, thanks a lot.

[Matias Da Silva]

Haha, 11 years later this post save us on CUCM 8.6.2, disabled "Inhibit restarts at PRI initialization" Works Excellent on the E1 affected.

THANKS A LOOOT.

[aamercado]

haha...I haven't logged into cco for so many years that I was surprise to see this update. I don't even do voip anymore....Nice my post has helped you 11 years later....makes me feel olllllddddddd!!!

[Jim Pilgrim]

Very helpful - here is the deubg of it not working:
*Oct 11 14:47:38.709: ISDN Se0/1/0:23 Q931: RELEASE_COMP pd = 8 callref = 0x8003
Cause i = 0x82AC18 - Requested circuit/channel not available

After Unchecking the box and a reset of the PRI it worked great!!!!

[Erick Bergquist]

How many DSPs (PVDMs) are in this module in slot 3? What type of NM is it?

I have only seen this cause code to date when there is a lack of DSPs or the DSPs are hung/stuck.

Can you do a 'show voice dsp'?