Subject: Re: [IPTEL] CPL: Timezone issues

From: [email-masked]
Date: Wed, 12 Jul 2000 08:20:49 -0400

From:  Tom Gray@MITEL on 07/12/2000 08:20 AM
It depends on how the system is implemented. If the preconditions based on time
are precomputed instead of being checked each time a call comes in, then there
may be a problem. The precomputation of time-based preconditions is a viable
way of implenting this in  a hardware so that the '<' and '>' operatiors do not
have to be implmented just the '=' .

I know that his isn't the most serious problem in the world but it is something
an implemetor should be aware of.

Henning Schulzrinne <[email-masked]> on 07/10/2000 04:19:08 PM

To:   Tom Gray/Kan/Mitel@Mitel
cc:   Jonathan Lennox <[email-masked]>, Rohan Mahy
      <[email-masked]>, [email-masked]

Subject:  Re: [IPTEL] CPL: Timezone issues

[email-masked] wrote:
>
> From:  Tom Gray@MITEL on 07/10/2000 04:14 PM
>
> Depending on how a system is implemented, the missing time case may cause a
> problem.

How can a time that never occurs cause a problem? By definition, there
aren't any SIP requests that arrive during that time, since it doesn't
exist... (Something about falling trees in a forest comes to mind...)

--
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs

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From: Stephen Thomas <[email-masked]>
Date: Mon, 17 Jul 2000 11:12:25 -0400

As if this subject wasn't a big enough rats' nest already, this was in the 
recent RISKS forum:

>Date: Thu, 6 Jul 2000 17:48:23 -0400
>From: "Mark Lutton" <[email-masked]>
>Subject: Australian DST rules changed for Olympics
>
>Several Australian states have changed the Daylight Savings Time rules so
>that DST will be in effect for the year 2000 Olympic Games in Sydney in
>September.  (late winter for them).  Normally DST begins in October.
>
>I suppose the benefits are substantial.  Quite a bit of electricity for
>stadium lighting will be saved.
>
>I wonder if anyone considered the costs and the risks.  This affects just
>about every computer in Australia, and many automated installations like
>radio stations, time-lock bank vaults and security systems.  Microsoft is
>taking it calmly and has issued a notice at
>http://www.microsoft.com/australia/support/timezone/2000.htm.
>
>I guess there was some reason they couldn't just schedule every event to
>start an hour earlier.

____________________________________________________________________
Stephen Thomas                                       +1 404 872 4887
TransNexus, Chief Technical Officer    [email-masked]

---

From: Rohan Mahy <[email-masked]>
Date: Mon, 17 Jul 2000 15:40:47 -0700

Hi,

The last time the Pope was in Brazil, the government postponed the 
beginning of Daylight Savings Time, because someone made a mistake and 
scheduled the satellite time for his visit according to the standard time 
UTC delta.  This kind of screw up happens fairly frequently.  Correctly for 
this requires either a "push" of timezone rules / UTC delta, or user action 
to "pull" the new rules.  Obviously, if you rely on user pull, some users 
will be out of sync for some period of time.

thanks,
-rohan