Subject: RE: "Does anybody really know what time it is?" :-)

From: Ami Amir <[email-masked]>
Date: Wed, 2 May 2001 09:35:52 +0300

Hi

I've been following the discussion with great interest. 

We should learn from the mobile network's experience. When you switch on
your phone - wherever you are, the NETWORK provides you with the local time
that is displayed on your screen. This functionally makes the most sense.

Keep in mind that timestamp might be very important for billing (e.g.
day/night rates), intelligent call redirects etc.

To apply to MEGACO - to my mind it makes sense that the MGC is the device
that sets the clock for the MG. I am not familiar enough with H.248 to
propose how this should be implemented, but it seems to me that the current
MG registration has already a time stamp. If that is the case, maybe there
should be a way for an MGC to reset the MG clock to its own timestamp?

Ami

 -----Original Message-----
From: 	Paul Long [mailto:[email-masked]] 
Sent:	Tuesday, May 01, 2001 8:28 PM
To:	'Megaco (E-mail)
Subject:	RE: "Does anybody really know what time it is?" :-)

Nurit,

Hey, it just occurred to me that the MG can't use the MGC timestamp to set
its own clock at least for the just-established association because the MG
has already reported its "time base" in the (required) timestamp it
previously sent to the MGC in its ServiceChange registration request. It
would have to unregister first and then re-register in order to use the new
setting. Maybe that was the intent, though.

You know, the more I think about it, the more convinced I am that there is
no reason to encode absolute time. Not even that it should be optional, or
it would be nice if a sender were able to, etc., but that there is really no
value in absolute time because the receiving entity will always apply a
delta to normalize the senders' time to its own. What does seem to be
needed, though, is some way for a receiver to know what time zone it and the
sender is in. But note that this feature would just be useful and not
essential.

Paul Long
ipDialog, Inc.

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]]On Behalf Of Nurit Shenhar
Sent: Tuesday, May 01, 2001 8:37 AM
To: 'Megaco (E-mail)
Subject: RE: "Does anybody really know what time it is?" :-)

Hi

We had a discussion about the time issue at the second half of January 2001.
(see subject: TimeStamp in registration replies). In this discussion we said
that the TimeStamp should be added to the ServiceChangeReply, and can be
used to set the MG clock according to the MGC clock. Was anything done about
it?

Nurit

---

From: "Paul Long" <[email-masked]>
Date: Wed, 2 May 2001 12:50:11 -0500

Ami,

In my mind, the timestamps don't need to be synched at all, and, in
particular, an MG's clock never needs to be set by the user or an MGC. In
order to display the local time on an MG--which is the only goal I think we
are all actually trying to achieve here--the MGC must simply know what time
zone the MG is in. Period. The MGC doesn't even need the MG's timestamps
because it can use it's own time base, adjusted for the MG's time zone. The
downside to this is that the MG itself will not have a sense of local time.
If it loses the association with an MGC, it can't display the time. But
isn't this the whole point of Megaco/H.248--to produce an extremely
lightweight MG? If we want a local-time feature in the MG that is setable by
the MGC, we need to add a new feature to the protocol, IMO.

BTW, "What time zone the MG is in," is kinda misleading because it implies a
location-based UTC offset. For example, the space program uses various UTC
offsets that are relative to an event, e.g., MET, rather than a location.
Cool, huh? Megaco being used on the space station or Mars (lotta end-to-end
delay, though). :-)

Paul Long
ipDialog, Inc.

-----Original Message-----
From: Ami Amir [mailto:[email-masked]]
Sent: Wednesday, May 02, 2001 1:36 AM
To: Paul Long; 'Megaco (E-mail)
Subject: RE: "Does anybody really know what time it is?" :-)

Hi

Ami