Issue 024 - DPWS - R1013 and R1015 should clarify directed discovery

[Ram Jeyaraman <Ram.Jeyaraman@microsoft.com>]

This issue is assigned the number 024. For further discussions on this issue, please refer to this issue number or use this thread.

 

From: Dan Driscoll
Sent: Wednesday, September 17, 2008 9:32 AM
To: Ram Jeyaraman
Subject: NEW Issue - DPWS - R1013 and R1015 should clarify directed discovery

 

Please defer discussions on this issue until a time this issue is accepted and is assigned a number.

 

Description:

DPWS Section 4 (Discovery) describes a method of sending WS-Discovery messages over an HTTP connection.  This request/response exchange is not described in WS-Discovery, and does not conform to the SOAP 1.2 HTTP binding.

 

A proposed issue in WS-Discovery (Issue 022) adds a request/response MEP for communicating to discovery proxies that is similar in functionality to this exchange.

 

Additionally, the specification is unclear about the HTTP addresses at which a device must support receiving this Probe message.

 

Proposed Resolution:

DPWS should reuse the WS-Discovery request/response proxy pattern for use with directed discovery to a known HTTP endpoint.

·         R1015 should require devices to implement the “proxy” side of the proposed WS-Discovery request/response pattern.  R1015 should also require that devices support receiving a directed Probe at any HTTP addresses where the device endpoint is available.  The supporting text should clarify that the device may also accept these Probes at other locations.

 

R1015: A DEVICE MUST support receiving an ad-hoc Probe SOAP ENVELOPE as an HTTP Request at any HTTP addresses where the DEVICE endpoint is available.

 

Clients may query a known HTTP endpoint for devices by sending an ad-hoc WS-Discovery Probe message in the HTTP request/response pattern described in WS-Discovery section xxx.

 

·         R1021 and R1022 should be updated to match the request/response pattern.

 

R1021: If a DEVICE matches a Probe SOAP ENVELOPE received as an HTTP Request, it MUST send a Probe Match SOAP ENVELOPE in the HTTP Response.

 

R1022: If a DEVICE does not match a Probe SOAP ENVELOPE received as an HTTP Request, it MUST send a Probe Match SOAP ENVELOPE in the HTTP Response with no ProbeMatch sections in the SOAP body.

 

·         Add the following clarifying text at the end of section 4:

 

How the CLIENT obtains the DEVICE HTTP address is not defined in this specification, and this HTTP address does not necessarily relate to HOSTED SERVICE addresses.