Minutes from 9-9-03 Notifications SC call

[Art Botterell <acb@incident.com>]

Notification Methods and Messages Subcommittee
9-9-03 12:30 EDT

Attending: Gary Ham, Walid Ramadan, Rex Brooks, Ori Warshenbrot, 
Jason Gilliam, Jerry Weltman, Tom Merkle, Eliot Christian, Carl Reed, 
David Hall, Art Botterell

Agenda:
ICS-201 project
DMIS CAP interface issues

Notes:

ICS-201 - David Hall has some thoughts on updating the data 
dictionary; Art and David will collaborate on those.  Query regarding 
the area/map representation has gone to GIS SC for guidance.

DMIS Interface - Gary Ham provided an overview of issues that have 
arisen in the course of DMIS developing a CAP interface:

* Type names: the current CAP schema includes a number of "anonymous" 
types... this breaks some implementation tools.  For the time being 
they're using a convention that the type name equals the 
corresponding element name; the SC agreed that this was appropriate. 
Eliot Christian suggested that the TC may need to create a shared 
collection of these types.  Rex Brooks agreed that it would be 
beneficial to have these in an importable schema.  Gary Ham will 
bring forward a proposal to include type names in the schema when we 
revise it.  Consensus was that this wouldn't impact implementations 
or the form of CAP message instances.

* SOAP encoding:  The initial DMIS implementation treats CAP 
transmission as an RPC call and thus SOAP-encodes the message body. 
As a result, the contents of the SOAP body are not, themselves, valid 
against the standard schema.  Eliot reported that Microsoft is 
avoiding such encodings due to interoperability problems between 
various SOAP implementations.  Carl Reed said OGC tries to avoid 
intrusions of higher-level protocols into message content.  Rex 
Brooks noted that WSRP is explicitly SOAP-based.  Art expressed 
concern that any deployment of an interface that features a 
non-validateable representation of the CAP message could have the 
practical effect of "forking" the standard, leading to 
transport-dependence and non-interoperability.  Gary Ham reported 
that DMIS will switch from the RPC-style interface to a 
message-oriented form where the SOAP body contents comply with the 
committee-standard schema.  He said this interface should be 
available by Friday.  The SC endorsed that choice, while 
acknowledging that this makes implementation somewhat more demanding. 
Art expressed hope that DMIS would then withdraw the non-compliant 
(RPC) interface in order to support a standards-based approach.

The subcommittee adjourned at 1:04 to make way for the TC meeting.