Intermittent Dropped Calls

[Ralph John Tampilic]

Hi,

Blessed day!

May we ask for your assistance regarding on our issue? There has intermittent dropped calls during volume of incoming call from PSTN.

But if only few calls, no issue.

PSTN -> PRI -> H323 -> Unity -> SIP Trunk -> CUCM

I have read some post on forum that "Enable Inbound FastStart" on Voice Gateway must be check. 

May we know if I'm going to do that will be resolved the issue or it may affects our calls?

Hope for your kind assistance.

Thanks and regards,

Ralph

[Manish Gogna]

Hi Ralph,

If the calls are being identified as failing during peak hours then it is more of a capacity/resource allocation issue, enabling the inbound faststart will not help. Check if you have enough PRI channels active when the calls are failing, if they are maxed out then its better to add another PRI line.

HTH

Manish

[Ralph John Tampilic]

Hi Robert and Manish,

Blessed day!

We have 60 channels and yes it was activated from Telco provider.

controller E1 0/0/0
pri-group timeslots 1-31
!
controller E1 0/0/1
pri-group timeslots 1-31

And I don't think if this has not enough channels because call was already connected then after 2 seconds it was dropped.

Regards,

Ralph

[Manish Gogna]

Hi Ralph,

Since you now mention that calls drop after getting connected, its a whole different issue now. You need to get the basic debugs "debug ccsip messages" "debug voice ccapi inout" "debug isdn q931" for a call that drops due to such a reason. The corresponding detailed callmanager traces from cucm will also help.

Manish

[Ralph John Tampilic]

Hi,

Please see attached SDL trace.

Calling Party is 02935-7964

and Called Party is 660.

Call time = 16:31

I have seen cause=41 what does it mean temporary failure?

I cannot leave a debug because it may suffer the VG.

Thanks and regards,

Ralph

[Robert Shaw]

It looks like this is failing at the H.323 stage between the Gateway and Unity.  You can see this line here in the SDL trace,

80626027.001 |16:31:01.198 |AppInfo  |TranslateAndTransport(156854)::wait_SdlCloseInd - ERROR: H245 signaling connection aborted!!!, err=0

We really would need to see some debugs from the Gateway as well as the SDL trace for the same call in CUCM.  If you are concerned with the gateway resources it is best practice to log debug traces to a Syslog server.  Solarwinds have taken over Kiwi Syslog server which you can download free for up to 5 devices.

http://www.kiwisyslog.com/

Has this ever worked or is it a new configuration?

[Ralph John Tampilic]

Hi  Robert,

Blessed day!

Thanks for your response. This is a new CUCM and new E1 from R2-digital to PRI, since lat December 2016.

I don't know why Unity still involved even the call already connected between IP phone and external.

Regards,

RJ

[Ralph John Tampilic]

Hi,

Here's what I've found in SDL traces using Translator X.

Regards,

Ralph

[Ralph John Tampilic]

Hi Robert,

Blessed day!

Please be advised that we have encountered again a drop call but the operator said that they are on conversation then suddenly she cannot heard anything (dead air).

We have captured the SDL traces and debug isdn q931 please see attached files.

Calling Party = 5794823 (outside caller)

Called Party = 660

Timestamp = May 10, 2017; 1:37 PM

Thanks and regards,

Ralph

[Robert Shaw]

Hi,

+5 to Manish for his suggestion.  I also don't think enabling Inbound Faststart will help.

On top of that we would need to see some configuration of your H.323 gateway.  Do you have enough timeslots configured under the controller interface?  Have you confirmed with the provider how many PRI Channels are configured for the service?

Thanks
Rob

[HARIS_HUSSAIN]

You have to collect the Logs for the Dropped Calls.

  1) You can collect on VG 

"debug voice ccapi inout"  and  "debug isdn q931"

Make sure you disable the Console logging and collect logs in Buffer as the call volume is hight.

2) You can collect CUCM SDL logs from RTMT for the duration

Please attach both the logs here to analyze further.