Re: MSC-News: Partial and Total ordering of MSC

Subject: Re: MSC-News: Partial and Total ordering of MSC
From: Aldo Buratti (
Date: Thu Nov 05 1998 - 16:33:09 GMT

The originator of this message is responsible for its content.
-----From Aldo Buratti <> to mscnews -----

Oystein Haugen wrote:

> Aldo Buratti skrev:

? skrev ?

>> I have a clarification request about the partial ordering of MSC
>> events. ......

> You must remember that the environment has no order. Actually there
> are no events on the environment at all in the formal interpretation.
> We cannot know what happens outside our MSC frame. If you think about
> it you will find this reasonable if though you sometimes know in which
> order environment events take place, but this must be described in
> another MSC referring to the one you use.

This means that the MSC frame cannot be treated as a 'special' axis ??
(please, read the following notes)

> Now I get very puzzled. The figure is _not_ what you say it is. Below
> I have shown how it should look like and what was actually sent to
> ITU. I would be very interested to learn that in your version it is
> different.
> ....

First of all, a clarification about the figure we are talking of:Despite
of the differences due to the "ENV" axis (we can talk about later), my
figure titled "MSC event_ordering_new" is equal to the picture you
attached, and it is what I consider the "right" picture.
Really, it seems strange to me that my copy of the Z.120 document is
different from the official one, since I took it from an on-line CD-ROM
in the IntraNet of a "primary telecom company". At the moment, I cannot
give you other details because I have no direct access to this "ITU-T
Recommendation Collection" CD-ROM.
I'll investigate !

I ask everyone interested with this topic to check his/her copy of Z.120
(please, don't send me a copy of Z.120)

>> ... about events on the same points...
>> .....
>> Don't you think that these widely used patterns (even in an informal
>> way), can be legitimated by adopting an "implicit" coregion ?
> This could have been another interpretation, but we decided rather to
> disallow the construction because we were not sure that your
> interpretation would be the only intuitive one.

Which other mis/interpretation could be made about events on the same
point ?

>> In other words, two incoming/outcoming events on the same point,
>> should
>> be treated as events occurring at "the same time", that is in a
>> random
>> order, that is like in a coregion.
> "In the same time" has absolutely no meaning in MSC. Again the reason
> for disallowing the construction was the risk of misinterpretation
> from human beings.

I apologize for my naive and rough expressions but, what I intend with
"two incoming/outcoming events at the same time" is"two
incoming/outcoming events where the order of receiving/sending cannot be
That is, a coregion.

Thank you, for your help.

                            Aldo Buratti

-----End text from Aldo Buratti <> to mscnews -----
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