Solved: Changing Disconnect cause on H.323 gateway in cas of ISDN failure

STEFAN CHRISTEN · ‎07-29-2009

Hi

We're running CUCM 7.1.2 and H.323 Gateways in each office. We are already using the HQ Gateway as backup in case of an ISDN failure in a remote office. By default the H.323 Gateways are sending the disconnect cause of "1" (Hex 81, unallocated or unassigned number, see debug below) in case of an ISDN Port failure.

Is there a command to change the disconnect cause (the H.323 one, not the ISDN disconnect cause) to something more accurate like Hex A1 "circuit out of order" or Hex A6 "network out of order"?

Any suggestions are welcome.

Many thanks in advance

Regards

Stefan

Nicholas Matthews · ‎07-30-2009

Hi Stefan,

What is happening is your pots dial peer goes into a 'down' state when the ISDN circuit goes down. This is similar to having a dial peer defined with no destination-pattern.

When the gateway does a dial-plan lookup, it sees no available dial peers and says that it does not have that number in it's dial-plan.

You may be able to enter this command to change that behavior:

no dial-peer outbound status-check pots

That would allow you try the call out the PRI, and would change the cause value.

Let me know if that helps.

-nick

View solution in original post

Nicholas Matthews · ‎07-29-2009

Hi Stefan,

You may want to look at some of these H323 configuration examples to solve what you're trying to do:

http://www.cisco.com/en/US/docs/ios/12_4t/12_4t11/htcause.html#wp1103228

hth,

nick

STEFAN CHRISTEN · ‎07-30-2009

Hi Nick

Many thanks for the reply.

I tried:

application

map

q850-cause 1 q850-cause 33

and it gave me following H.323 message when the ISDN was down:

187499: Jul 30 08:41:36 CEST: //1405/8055C7051D00/H323/cch323_h225_send_release: Cause = 33; Location = 0

But unfortunately it also changes the cause if an "unallocated or unassigned number" is received in an ISDN disconnect :-(

187667: Jul 30 10:08:25 CEST: ISDN BR0/0/0 Q931: RX <- DISCONNECT pd = 8 callref = 0xD2

Cause i = 0x8281 - Unallocated/unassigned number

187671: Jul 30 10:08:25 CEST: //1408/00A895262000/H323/cch323_h225_send_release: Cause = 33; Location = 0

I don't want to map disconnect causes, I really only like to change the disconnect cause when the ISDN interface is down because "unallocated or unassigned number" seems to be wrong in my opinion. Usually when an "unallocated or unassigned number" is received via ISDN there is no need to hunt to the next gateway because it will also receive "unallocated or unassigned number".

Anyway, you helped me again and maybe you'll find some other (maybe hidden command).

Have a nice day

Regards

Stefan

Nicholas Matthews · ‎07-30-2009

Hi Stefan,

What is happening is your pots dial peer goes into a 'down' state when the ISDN circuit goes down. This is similar to having a dial peer defined with no destination-pattern.

When the gateway does a dial-plan lookup, it sees no available dial peers and says that it does not have that number in it's dial-plan.

You may be able to enter this command to change that behavior:

no dial-peer outbound status-check pots

That would allow you try the call out the PRI, and would change the cause value.

Let me know if that helps.

-nick

STEFAN CHRISTEN · ‎07-30-2009

Hi Nick

You're my H.323 gateway hero ;-)

With the "no dial-peer outbound status-check pots" the gateway sends a "Requested channel not available" (44, Hex AC) back to the CUCM when the ISDN interface is down. Which seems to be more appropriate to me.

189361: Jul 31 08:26:13 CEST: //1423/00760A0A2700/H323/cch323_h225_send_release: Cause = 44; Location = 0

Many thanks for your support and have a nice weekend

Regards

Stefan