Discovery and Metadata Exchange Message Patterns
Other versions of this page are also available for the following:
.gif "A hyphen indicates that the information in this topic is not relevant for this platform, or that the platform does not support the API that is listed.")
.gif "A checkmark indicates that the information in this topic is relevant for this platform, and that any API listed is also supported on this platform.")
8/28/2008
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.
.gif "Bb821789.fd1115b4-1d5f-49b4-9dc6-0c11368cbc3f(en-us,MSDN.10).gif")
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.
- Hello
- Probe
- ProbeMatches
- Resolve
- ResolveMatches
- Get (metadata exchange request)
- GetResponse
- Bye