Use of wsa:RelatesTo in WSN

["Vambenepe, William N" <vbp@hp.com>]

Hi all,

Following up on my AI from the F2F, here are thoughts on how WSN might
want to specify use of wsa:RelatesTo if the TC decides to do so
(assuming wsa:RelatesTo survies the W3C process but so far I haven't
heard that anyone is trying to get rid of it).

First, a reminder of how wsa:RelatesTo is defined in the latest draft
[1] of Ws-Addressing.

/wsa:RelatesTo
    This OPTIONAL (repeating) element information item contributes one
abstract [relationship] property value, in the form of a (URI, URI)
pair. The [children] property of this element (which is of type
xs:anyURI) conveys the [message id] of the related message. This element
MUST be present if the message is a reply.

/wsa:RelatesTo/@RelationshipType
    This OPTIONAL attribute (of type xs:anyURI) conveys the relationship
type as a URI. When absent, the implied value of this attribute is
http://www.w3.org/2005/02/addressing/reply.

Based on this, WSN could define the following @RelationshipType URIs for
use in notification messages (you'll excuse my shortened URI syntax):

http://oasis/wsn/subscriptionMessage: the URI in RelatesTo is the
messageId of the subscription message that caused this notification to
be delivered.

http://oasis/wsn/subscriptionCreationResponse: the URI in RelatesTo is
the messageId of the subscription creation message that was sent when
creating the subscription that caused this notification to be delivered.

http://oasis/wsn/situationUpdate: the URI in RelatesTo is the messageId
of a previous notification message. The current notification message is
an update of the situation that caused the previous message to be sent.
For example, this is used if the previous message was to notify that a
given service has stopped and the present message notifies that the same
service has now restarted. This provides basic event correlation.

Obviously none of these would be required, but by defining these URIs
and the attached semantics we would allow people to exchange this useful
information in an interoperable way.

Regards,

William


[1] http://www.w3.org/TR/2005/WD-ws-addr-core-20050215/