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Discovery and Metadata Exchange Message Patterns (Windows Embedded CE 6.0)

  • Article

1/6/2010

Device hosts and client applications that are compliant with Device Profile for Web Services (DPWS) communicate over the network using a series of SOAP messages sent using UDP and HTTP.

The following diagram shows an overview of the expected UDP and HTTP traffic between a device host and client application.

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Hello, Bye, Probe, Resolve, and Get messages are all generated without network solicitation; these messages are used to announce device state or to issue a search request. ProbeMatches, ResolveMatches, and GetResponse messages are responses to Probe, Resolve and Get messages.

Applications and hosts send messages using various protocols, as shown in the following table.

Message Protocol

Hello, Bye, Resolve, ResolveMatches

UDP

Get, GetResponse

HTTP or HTTPS

Probe, ProbeMatches

UDP in most cases, but HTTP or HTTPS in a directed discovery scenario

For more information about directed discovery message patterns and troubleshooting application using directed discovery, see this Microsoft Web site.

The following list shows the typical sequence of messages. Not all messages are mandatory.

  1. Hello
  2. Probe
  3. ProbeMatches
  4. Resolve
  5. ResolveMatches
  6. Get (metadata exchange request)
  7. GetResponse
  8. Bye

See Also

Concepts

About Web Services on Devices