RE: Issue 131 - DPWS - Problem with SOAP address of services on adevice

I can’t recall if we had a discussion about this on a prior call.

I see this as an interesting implementation point, but not something we need for the core specification. DPWS intentionally leaves URL topology completely up to the implementer, because many of the choices here are very implementation-specific: some devices host everything on a single URL for simplicity (they use EPR/Action for message dispatching); others host services on unique URLs. Some devices may have their hosting URLs specified during development, and may not be able to change them as easily as they can autogenerate a new device ID.

Accidental impersonation by other services is not the only consideration in determining a URL topology. Some devices host on port 80—that decision has functional implications, too. The list is pretty lengthy, and this is a relatively constrained topic.

We could possibly produce some text about this, but I think we can spend an awful lot of time in the TC producing implementation guides when we should really be focusing on the specifications.

Thanks!

--D

From: Ram Jeyaraman [mailto:Ram.Jeyaraman@microsoft.com]
Sent: Tuesday, December 16, 2008 8:28 AM
To: ws-dd@lists.oasis-open.org
Subject: [ws-dd] Issue 131 - DPWS - Problem with SOAP address of services on a device

This issue is assigned the number 131. For further discussions on this issue, please refer to this issue number or use this thread.

From: Elmar Zeeb [mailto:elmar.zeeb@uni-rostock.de]
Sent: Monday, December 15, 2008 3:25 PM
To: Ram Jeyaraman
Subject: New Issue for DPWS

Description: Problem with SOAP address of services on a device
Document: wsdd-dpws-1.1-spec-wd-02
Line number:

There is the following scenario: A client is using a service on a device. This device leaves network and can't send a bye message. A new device joins network. The new device hosts a service of the same type that has the same transport address as the service before. The new device sends a hello message. The client won't be able to detect that it uses another instance of the service, that is hosted on another device.

Proposed solution: Service addresses should include the device id or should be unique.

--

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  Dipl.-Inf. Elmar Zeeb

  Universität Rostock, Fakultät f. Informatik und Elektrotechnik

  Institut f. Angewandte Mikroelektronik und Datentechnik

  University of Rostock, Faculty of CS and EE

  Institute of Applied Microelectronics and Computer Engineering,

  18051 Rostock

  Deutschland/Germany

  Tel. : ++49 (0)381 498 - 7262

  Fax  : ++49 (0)381 498 - 7252

  Email: elmar.zeeb@uni-rostock.de

  www  : http://www.imd.uni-rostock.de/, http://www.ws4d.org/

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