Subject: Re: [Megaco] How can MGC detect MG's ring timer expired?

From: [email-masked]
Date: Wed, 12 Jun 2002 08:32:32 +0530

Hi,

MGC should sent "g/sc" in event descriptor and "al/ri" in signal descriptor with
ADD/MODIFY command to MG.

If the ring timer expired then MG will notify the "g/sc" event with signal Id=
"al/ri" and method= TO to MGC.

regards,
Amaresh

노정민 <[email-masked]> on 06/12/2002 06:59:30 AM

To:   [email-masked]
cc:    (bcc: Amaresh Ram/HSS)

Subject:  [Megaco] How can MGC detect MG's ring timer expired?

Hi all.

I'm developing MEGACO Media Gateway.

I was confused about how can MGC detect MG's ring timeout.

When MGC sent ring signal ( "al/ri") to MG then MG start timer and generate ring
signal to user.

If ring timer expired then how can MG notify it to MGC?

Or how can MGC detect ring timer expired?

My goal is MGC sent busy tone to calling MG in this case.

------------------------------------------------------------------------------
MG                                                     MGC
MG

--------------------------------> digit

----------------------------------> "al/ri"
|
|
ring timer expired
|
                                                             ?
<------------------------------------

cg/bt <----------------------------

---

From: Al Varney <[email-masked]>
Date: Wed, 12 Jun 2002 10:53:46 -0500

A comment on your "goal" -- see below.

At 08:32 AM 6/12/02 +0530, [email-masked] wrote:

>³ëÁ¤¹Î <[email-masked]> on 06/12/2002 06:59:30 AM
>>
>>Hi all.
>>

    Not to say this is a bad approach, but a major purpose of various call 
progress tones in telephony is to provide information to the caller, so he 
or she can make an intelligent decision about when to retry an unsuccessful 
call.  For many callers, ring timeout is a relatively unexpected 
occurrence.  This implies you should think carefully about how the caller 
will behave when it occurs.

    Assuming the caller is initially hearing Ring Tone (ringback), it is 
confusing to listen to Ring Tone for a period and then have it switch 
quickly to Busy Tone.  Many callers will think this is a temporary failure 
in the telephone system or the called telephone, and try the call again 
(and perhaps a third time).  I assume you want to avoid a second call 
attempt when it also is likely to time out.  An announcement ("The call is 
not being answered.  Try again later.  Goodbye.") followed by disconnecting 
the call would most likely avoid a repeat call attempt until a later time.

    In this particular situation, there probably isn't any TONE that would 
be successful at motivating the desired behavior.  Try to imagine what tone 
following a period of Ring Tone would convince YOU not to re-try the call 
again.

    And try to imagine the caller's frustration at unexpected behavior of 
the telephone system.  Frustrated callers make fewer and shorter calls, and 
sometimes complain to authorities or the service provider.  That's never 
good for the equipment/software vendor.

Al Varney -- just my opinion

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---

From: Al Varney <[email-masked]>
Date: Wed, 12 Jun 2002 10:53:46 -0500