Issue 134 - DPWS - No reliable way to retrieve discovery metadataof devi

This issue is assigned the number 134. 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 3:40 PM
To: Ram Jeyaraman
Subject: New Issue for DPWS

Description: No reliable way to retrieve discovery metadata of devices
Document: wsdd-dpws-1.1-spec-wd-02
Line number:

All type fields in WS-Discovery and DPWS are optional. There should be ONE way to retrieve the types, supported by a device, without probing for every type. As the types should be optional in the discovery metadata, to solve problems related to message size, the types should be listed in the relationship metadata section. The increased message size of WS-Transfer messages is not as problematic as an increased message size within WS-Discovery (UDP fragmentation). At the moment there is no reliable way to retrieve all device types of a device. This problem exists especially for generic clients.

The same problem exists for scopes. This problem is less problematic as scopes don't express the device functionality.

Proposed solution: Make Host field in relationship metadata mandatory and also make types field in the Host field mandatory.

There is no proposed solution for the scopes problem.

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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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