10/03/2006 1:05 PM
post5666
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Comments from Matt Roberts (IBM UK)
The comments below were posted on a WS-Notification mailing list by Matt Roberts. However as he does not have an OGF
login I am posting them here for him with his permission.
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Please find attached a copy of the INFOD specification that I volunteered to take a look at on last week's WSN call. I
have included some comments in the document that highlight my thoughts/concerns etc.
I must qualify my review with two caveats - firstly I was pressed for time (so I apologize if I have missed things I
would normally have picked up) and secondly I'm not sure I was able to give my efforts sufficient time to get a full and
detailed view of what the specification is trying to achieve. This may mean that I have misinterpretted things and lead
my comments down a blind alley.
As far as I can tell, INFOD is a specification which is aimed at providing a mechanism for creating the association
between a producer of events, and a consumer in some way which can be more advanced than the standard WSN pattern. In
particular there is a INFO Registry service to which all producers and consumers register, and in which an INFOD
subscription is created (different to a WSN subscription) which indicates that types of messages that consumers wish to
receive. The INFOD Registry is then responsible for matching subscriptions to the available publishers, and then
invoking an operation on the publisher to indicate the set of consumers to which it should send notifications. (The
Registry is a bit like a NotificationBroker, but notifications flow directly from producer to consumer rather than
through the broker).
The only item from WSN that seems to be used in the Notify operation (mainly covered in section 3 of the INFO doc
attached). My primary concern is whether the INFOD folks are intending to take a copy of the Notify operation, or use
the one we define in WSN. There are several areas in the document (notably the Schema document in 5.10 and parts of 3.1.
1) where they seem to copy the Notify operation into an INFOD namespace, which strikes me as a pretty weak form of reuse
(ie regular WSN apps wouldn't be able to invoke this new variant of Notify because of the different namespace). They
also define a new WSA Action URI to be used when invoking this Notify operation, which is a violation of the WSN spec (
if they are trying to reuse rather than copy).
I have attached comments in the document below that highlight the specific areas that I have identified - I think is
would still be very useful for someone from INFOD to present to the WSN committee to give some more background on how
this will be used and clear up any misconceptions I may have stumbled into!
Cheers,
Matt
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