Boxcarring and reliability

[David Hull <dmh@tibco.com>]

Following the example of the reliability specs, we distinguish between
producing and delivering.  If we boxcar a set of Notifications in a
Notify message, are they required to be delivered atomically?  IMHO,
boxcarring is a transport-level optimization and atomicity should be
handled separately (it should be possible to handle a set of messages
atomically even if they happen to be transmitted in different SOAP
envelopes).

Ideally, each of the boxcarred messages would have its own delivery
status.  E.g., I am able to process the first five of ten boxcarred
messages and acknowledge them, and then my process crashes or the
network goes down.  To accomplish this, though, the reliability layer
would have to know about the boxcarring.  This argues for handling
boxcarring outside WSN (WS-Boxcarring, anyone?  WS-Polling is already
underway ...)

Thoughts?