Re: [wsn] Boxcarring and reliability

[David Hull <dmh@tibco.com>]

Martin Chapman wrote:

Boxcarring means that notify messages are bundled in a single soap
message. ws-rx works at the soap level so it doesn’t need to know about
boxcarring of notify messages.
  

Right.  So it looks not to be the tool I'd need if I wanted each notification to have its own delivery status.

The question is not so much what WS-RX does, but what semantics should we define.  In particular, are we producing and delivering SOAP envelopes or notifications?  Naturally, I lean toward the latter.

FWIW, I'm more and more convinced that there should be some sort of SOAP-level boxcarring standard that allows multiple SOAP envelopes to be sent transparently in a single wrapper (most likely itself a SOAP envelope).  This should be able to compose with the other WS-*, so that it would be possible to acknowledge individual messages that happened to travel in the same wrapper (or authorize/authenticate each separately, or re-route them to different places, or whatever).

Martin.

  

-----Original Message-----
From: David Hull [mailto:dmh@tibco.com] 
Sent: Wednesday, January 04, 2006 10:32 PM
To: wsn@lists.oasis-open.org
Subject: [wsn] Boxcarring and reliability


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?