Pub sub

Some proposed text for pub/sub:


Publish and subscribe (pub-sub) is a style that  involves one or more
sources
sending (publishing)  messages to one or more receivers (subscribers),
where each subscriber has
stated interest in receiving such messages. 

There are a number of mechanisms that can be used to support the
distribution of messages. 
In a simple case, a publisher may only support one subscriber (e.g. a
network device 
that signals alarms to a manager), in which case simple one-way or sync
request/response 
may be used. When multiple publishers and subscribers are allowed,
message distribution may occur at 
the protocol level (e.g. udp), or though an intermediary distribution
service (e.g. a web service) that takes on
the responsibility of distributing the messages to interested parties.

Implicit in the pub/sub model is the act of subscribing, which is a
mechanism that each 
subscriber uses to express interest in particular messages. This act may
involve listening 
on a certain transport channel (e.g. a udp multicast port), registering
direct 
with a publisher, or registering with an intermediate distribution
service.

There are a variety of ways of declaring interest in a message which
include 
expressing interest in messages from certain publishers, messages with 
certain content (content based filtering), 
and messages communicated on certain "channels" or bindings.

 

_________________________________________________________________
Martin Chapman                                 500 Oracle Parkway
Consulting Member of Technical Staff           Ms 1op641
Oracle                                         Redwood Shores,
P: +1 650 506 6941                             CA 94065
e: martin.chapman@oracle.com                   USA

Received on Thursday, 14 November 2002 17:30:13 UTC