Lifetime of GroupID

[Tom Rutt <tom@coastin.com>]

The current text states:
"
3.1.1 GroupId Element
This REQUIRED element is used to specify a group of messages. This 
element MUST have a
globally unique identifier as its value. The syntax of this 
identification is URI, as defined in
[RFC2396]. It is RECOMMENDED to use a syntax of Message-ID, as defined 
in [RFC2392]. This
element contains the following attributes:
- a removeAfter attribute
(1) removeAfter attribute
This is an OPTIONAL attribute. This attribute is used to specify the 
time the GroupId can be
removed from the RMP tracking mechanism for GroupId and SequenceNumber 
elements. Both
sender and receiver MUST maintain the value of GroupId element until 
either one of the following
two events occur:
- The sender sends a Message with the value of “End” in the status 
attribute.
- The time specified in the removeAfter attribute has passed.
The format MUST be expressed as UTC and MUST conform to a [XML Schema] 
dateTime. If
omitted, the value SHOULD be considered as ‘forever’.

"

It seems that this text could be modified to accomodate several
concerns that have been expressed regarding lifetime of duplicate
elimination and sequence preservation.

I we retain sequenceNumber as optional, we need to clarify what the
semantics of removeAfter are for a simple ack only case (i.e., sequenceNumber not present).  Perhaps it would only pertain if duplicate elimination is requested (and then it would be the lifetime of memory for duplication elimination for that message).  

If we have the case of duplicateElimination with SequenceNumbers then 
the removeAfter attribute is the lifetime for the persistent state
required for duplicate elimination for that group.  

For duplicate elimination and ordered delivery the text is probably ok as is.

Tom Rutt

----------------------------------------------------
Tom Rutt		email: tom@coastin.com; trutt@fsw.fujitsu.com
Tel: +1 732 801 5744          Fax: +1 732 774 5133