RE: Issue: Synch/Asynch Web services

Could you list a couple of examples of permutations it misses?

Hao

-----Original Message-----
From: Cutler, Roger (RogerCutler) [mailto:RogerCutler@chevrontexaco.com]
Sent: Tuesday, August 12, 2003 10:46 AM
To: He, Hao
Cc: www-ws-arch@w3.org
Subject: RE: Issue: Synch/Asynch Web services


My personal opinion is that your analysis hits the high points --
probably the 80-20 -- but probably not all the crevices and
permutations.

-----Original Message-----
From: He, Hao [mailto:Hao.He@thomson.com.au] 
Sent: Monday, August 11, 2003 6:28 PM
To: Cutler, Roger (RogerCutler)
Cc: www-ws-arch@w3.org
Subject: RE: Issue: Synch/Asynch Web services


Hi, Roger,
 
Here is my understanding about Synch/Asynch Web services.  Is it over
simplified?
 
Suppose we have two agents in a well-controlled environment (super fast,
reliable network). Agent A sends a message m1 to Agent B and expects
Agent B to return a message m2, however long it may take. This scenario
seems to me, is a typical case of sync Web services. The essences of
this process are: 1. that Agent A can relate m1 and m2 by sequence
(sending m1 to B is prior to receiving m2 from B). 
2. that there can be no other messages between two related messages.
 
If we remove those two constraints, the process becomes async. Agent A
can send a number of messages to Agent B after sending m1.  When it
receives m2 from Agent B, it can relate m1 and m2 together using other
mechanism, however that mechanism may be.
 
Interestingly, a process can be sync at the infrastructure level but be
async at the application level. For example, m2 can be a receipt rather
than final results an application intends to get. 
 
Hao