[cisco-voip] SCCP/SDL trace question re:transfer

[Ed Leatherman]

Wes,

On a successful call, (same exact call flow/numbers/etc) Same gateway IP's,
albeit potentially different PRI ckt's on each. We get the following
sequence of events for the transfer:

Successful:
22:56:37 Q931 out -> SETUP
22:56:38 SCCP IN <- Unity hits transfer second time
22:56:38 Q931 IN <- CALL_PROC
<various MGP/media upkeep>
22:56:39 Q931 IN <- PROGRESS
22:56:47 Q931 IN <-CONNECT
22:56:47 Q931 OUT -> CONNECT ACK
22:56:47 SCCP IN <- Unity "EndCall"
<Unity drops out of both legs>
<CUCM MGCP sets up media between the external caller and external party
gateways>


Comparing the same messages on the failure:
22:58:37 Q931 out -> SETUP
22:58:38 SCCP IN <- Unity hits transfer second time
22:58:38 Q931 IN <- CALL_PROC
<various MGP/media upkeep>
22:58:39 Q931 IN <- PROGRESS
22:58:50 SCCP OUT -> DisplayNotify "Cannot Complete Transfer"
22:58:50 Q931 IN <-CONNECT
22:58:50 Q931 OUT -> CONNECT ACK
22:59:06 SCCP IN <- Unity "EndCall"
22:50:06 Q931 OUT -> DISCONNECT (to the external site we're trying to
Transfer To)
..
22:59:43 Q931 IN <- DISCONNECT (original caller hangs up)


We don't seem to get ALERTING back when calling this destination at all.







On Tue, Sep 2, 2014 at 10:48 AM, Wes Sisk (wsisk) <wsisk at cisco.com> wrote:

>  Ed,
>
>  Unity doesn’t parse the soft keys sent from UCM to Unity to understand
> if “transfer” is available. Unity just blindly sends transfer and hopes the
> call completes.
>
>  I believe Progress is insufficient in UCM to enable transfer, usually
> have to wait for Alerting.
>
>  Attempting to replicate this with an SCCP phone is marginal value - SCCP
> phones implement the softkey set received from UCM. Thus the phone won’t
> allow you to send transfer when UCM has not activated that soft key.
>
>  Why is the egress call stopped in the progress state?
>
>  -Wes
>
>  On Aug 31, 2014, at 2:58 PM, Ed Leatherman <ealeatherman at gmail.com>
> wrote:
>
>  Hello!
>
>  I'm trying to help chase down a intermittent issue where Unity needs to
> transfer a caller off-site to an answering service, and sometimes the
> transfer doesn't complete and the caller gets left on-hold. I was hoping
> someone could explain a message i'm seeing in the traces during a failure.
>
>  SCCP integration to unity connection. 9.1 software versions on both CUCM
> and Unity. MGCP to PRI gateways. All gateways are set to offnet and service
> parameter is configured to allow transfers between offnet to rule that out
> as a issue.
>
>  On the trace side of things, for the transfer leg on a failure I see:
> 19:55:27.146 : Unity "presses transfer" , dials out the digits
> 19:55:29.853 : Q931 IN from PSTN for the transfer leg,  PROGRESS message
> 19:55:29.855 : CUCM OUT to Unity: Call State Ring out
> *19:55:41.020 : CUCM OUT to Unity: DisplayNotify timeOutValue=15
> notify='Cannot Complete Transfer' content='Cannot Complete Transfer' ver=12*
>
>  It looks like an abnormal amount of time for the call to connect, is
> that a possible reason for the "Cannot Complete Transfer" message? Is the
> timeout tweakable someplace?
>
>  On successful tries, the transfer leg connects faster (less than 10
> seconds). So far we haven't found anything else different on our own; have
> a TAC case open on it but getting shuffled between groups now (unity team
> wants CUCM team to look at it).
>
>  Unity never seems to retrieve the caller from hold or try again,
> eventually the caller hangs up (I see the the DISCONNECT message from PSTN)
> at which point that call leg gets torn down.
>
>  Any ideas much appreciated
>
>  Ed
>
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>
>


-- 
Ed Leatherman
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