I don't agree with synchronizing clocks. None of the time elements in the
message service spec are absolute times as far as I recall. They are
intervals. The state of the art of timing should be good enough to let
each end time its own intervals and not to need a timer accuracy parameter
(here, I agree with Chris). The CPA has one or two absolute times but the
intervals with which they are associated are measured in days or longer -
again no synchronization or timer accuracy requirement is needed.
I think I am repeating myself but just to make sure: The real problem is
that the message service specification does not state where each of the
reliable messaging parameters (and perhaps other also?) is located. 10.2
and 10.2.1 Delivery semantics say "either the CPA or the message header".
For the rest of the parameters, nothing is said at all about where they are
found. This is not an implementer's choice. Each one must be specified as
being in the message header or in the CPA.
Regards,
Marty
*************************************************************************************
Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown Hts, NY 10598
914-784-7287; IBM tie line 863-7287
Notes address: Martin W Sachs/Watson/IBM
Internet address: mwsachs @ us.ibm.com
*************************************************************************************
Dale Moberg <dmoberg@cyclonecommerce.com> on 08/01/2001 06:55:48 PM
To: ebXML Msg <ebxml-msg@lists.oasis-open.org>
cc: ebxml-cppa@lists.oasis-open.org
Subject: msh TimeAccuracy RE: T2 Reliable Messaging w/o CPA or VIA...
>> mshTimeAccuracy
>> >>>This is the accuracy to which a recipient of a message claims
to keep their internal
>> system clocks. This should probably be part of a CPP and not
vary from message to message
>> therefore it does not need to be in the MessageHeader
>> [David Fischer] Agreed, but what if there is no CPP? I'm not
sure why this is necessary.
Chris Ferris>It isn't represented in the CPP, nor should it be. I have
repeatedly expressed my
>belief that this is unnecessary at best, and more likely
unimplementable in any event [1].
>If anything, I could see parties agreeing to a requirement that their
respective
>system's system clock be synchronized using something like NTP or some
similar
>service and having this reflected in some manner within the CPP/A, but
not mshTimeAccuracy!
>I for one would like to see this removed from the 1.1 specification.
I agree with Chris that the use of
NTP to synchronize clocks at a distance
is something that is suitable for a CPA
and that the use of NTP
or XNTP or whatever could be
advertized in a CPP. I also agree
that putting the mshTimeAccuracy
in the MessageHeader
is definitely excess baggage!
Should be removed.
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