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CUCM alerting while call is busy

Hi all.

Yesterday i faced with problem:

Ringing tone is generated to IpPhone1(from CUCM i guess) while call declined by customer.

Design

IpPhone---CUCM---SIPtrunk---Redundant Voice gateways---E1 PRI --- PSTN---Customer Phone

On the voice gateway:

debug isdn q931

i see message  "Busy received" and channel is cleaned.

But even after channel clearing IPphone keep receiving ringing tone for about 30 sec.

If call is answered - no problems. Normal clearing and call termination.

If no channels available or all ports are shutdown no rerouting via redundant gateway occur.

I guess Voice gateway do not send some important message or waits for some event but i cant firure up for what. Maybe i missed something important in config.

Configuration of Voice GW is appended.

Any help is greatly appreciated.

2 ACCEPTED SOLUTIONS

Accepted Solutions
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Hi oleg.

add voice call disc-pi-off to your config.

HTH

Regards

Carlo

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"The more you help the more you learn"

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View solution in original post

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From the logs,

When the Telco sends a disconnect, it sends a PI (progress indicator-perhaps plays a prompt rather that the usual disconnect), hence as far as the gateway is concerend the call is still in progress and therefore does not send a disconnect to cucm

Oct 25 09:00:00.042: ISDN Se0/0/0:15 Q931: RX <- DISCONNECT pd = 8  callref = 0x80A1

        Cause i = 0x8491 - User busy

        Progress Ind i = 0x8288 - In-band info or appropriate now available

*Oct 25 09:00:00.042: ISDN Se0/0/0:15 Q931: call_disc: PI received in disconnect; Postpone sending RELEASE for callid 0x8041

Detailed explanation of this is below:

The debug Isdn q931 command output shows this message when the Public Switched Telephone Network (PSTN) user hangs up the call:

ISDN Se1/0:15 Q931: call_disc: PI received in disconnect; Postpone sending RELEASE for callid 0x8012

Resolution

Issue the voice call disc-pi-off command on the gateway so the gateway treats a disconnect message with a Progress Indicator (PI), as it treats a standard disconnect without a PI, (issue the voice call disc-pi-off command in global configuration mode).

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"opportunity is a haughty goddess who waste no time with those who are unprepared"

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View solution in original post

9 REPLIES 9
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VIP Mentor

Oleg,

This is not the first time I have see this. It seem to be common to sip trunks...

Can you do a test call and send the ff:

debug isdn q931

debug ccsip messages

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"opportunity is a haughty goddess who waste no time with those who are unprepared"

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Appended this debugs.

Where xxxxxxx - calling number, yyyyyyy - called number.

Call from Ipphone to pstn user.

I see from ccsip log - voice GW DO NOT SEND any message after user busy reseived. Only SESSION PROGRESS instead of BYE or CANCEL.

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Can you please enable the debigs together. I need to correlate isdn logs to sip logs...

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"opportunity is a haughty goddess who waste no time with those who are unprepared"

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Here are concatenated debug.

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Hi oleg.

add voice call disc-pi-off to your config.

HTH

Regards

Carlo

Please rate all helpful posts

"The more you help the more you learn"

Please rate all helpful posts "The more you help the more you learn"

View solution in original post

Highlighted

From the logs,

When the Telco sends a disconnect, it sends a PI (progress indicator-perhaps plays a prompt rather that the usual disconnect), hence as far as the gateway is concerend the call is still in progress and therefore does not send a disconnect to cucm

Oct 25 09:00:00.042: ISDN Se0/0/0:15 Q931: RX <- DISCONNECT pd = 8  callref = 0x80A1

        Cause i = 0x8491 - User busy

        Progress Ind i = 0x8288 - In-band info or appropriate now available

*Oct 25 09:00:00.042: ISDN Se0/0/0:15 Q931: call_disc: PI received in disconnect; Postpone sending RELEASE for callid 0x8041

Detailed explanation of this is below:

The debug Isdn q931 command output shows this message when the Public Switched Telephone Network (PSTN) user hangs up the call:

ISDN Se1/0:15 Q931: call_disc: PI received in disconnect; Postpone sending RELEASE for callid 0x8012

Resolution

Issue the voice call disc-pi-off command on the gateway so the gateway treats a disconnect message with a Progress Indicator (PI), as it treats a standard disconnect without a PI, (issue the voice call disc-pi-off command in global configuration mode).

Please rate all useful posts

"opportunity is a haughty goddess who waste no time with those who are unprepared"

Please rate all useful posts

View solution in original post

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+5 Carlo. Keep the good work going.

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"opportunity is a haughty goddess who waste no time with those who are unprepared"

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..and +5 to Aok for always giving excellent and detailed answers.

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"The more you help the more you learn"

Please rate all helpful posts "The more you help the more you learn"
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TY guys. Now busy calls are threated correctly.

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