Subject: Re: questions on digit maps and digit timers

From: Michael Brown <[email-masked]>
Date: Wed, 8 Dec 1999 15:35:57 -0500

Good day,

   I apologize for the delay in responding to your post. I have interspersed
comments with <MB> which I think addresses your questions.

Michael

Wai-tak Siu wrote:

> Hi,
>     I understand that Brian proposed an alternative way to digitmap
> descriptors, but he did not address the confusing descriptions of the
> digit timers.
>     In section 7.1.13 DigitMap Descriptor, the third item "If the
> DigitMap specifies that a variable number of ..." on short digit timer
> (a variable number of digits needed) seems to conflict with the second
> item on long timers (at least one more digit is needed for a match).
> From the sample digitmap at the end of the section, the short timer is
> used when no more digits are needed to provide a match. Therefore, the
> third item is wrong.

<MB> I understand the confusion about the third item.  The problem is that
the "variable" number of digits literally means just that. It is a veiled
reference to the use of "." in a digit map which means to collect any number
digits. I just looked at the text in the protocol and there currently no
mention of the usage of ".", so we probably should add a sentence. Note that
the "." is used in the example digit map in the last pattern.

>
>     Besides, I don't see the reason to specify the type of digit timers
> in the digitmaps (i.e. to use S or L in the digitmaps) because the
> protocol defines where a specific timer should be used. In particular,
> the long digit timer in the middle of a pattern is unnecessary from long
> timer's definition. We still need a timer identifier ('T' or something)
> to indicate if a timer is needed at the end of a pattern. If needed,
> this is a short timer by definition.

<MB> The definitions of the use of the timers is only the default behavior,
but it by no means describes the use of timers for all digit collection
scenarios which include variants for different markets/countries as well as
for application specific digit collection such as CLASS Screen List Editing.
The explicit specification of the timers is to provide that type of
flexibility.

>
>     Also, version 12 does not mention how digit timers should be used if
> digit maps are not used in collecting digits (e.g. event action is
> accumulate other than digitmap). Brian proposed to get rid of Action
> indicator in the Event descriptor. However, an MGC can still requests
> the gateway to notify digits one by one, or notify the first digit and
> accumulate/quarantine the rest.

<MB> You are right that there is no mention of the use of timers in the
above cases. It is assumed that if the digit map is not used that one of two
things happens. Either the MG has the intelligence and knowledge of dialing
plan (inherent digit maps) and can apply the timers appropriately (somewhat
unlikely) or that digit collection and timing is under direct micro
management control of the MGC. The default behavior would be that the MG
would be instructed to recognize digit events and they would be notified to
the MGC individually and immediately upon reception.

>     Thanks.
> Waitak
> Cisco Systems