"When writing a WCF client application you need to know the endpoint address of the service you are calling. In many situations the endpoint address of a service is not known in advance or the address of the service changes over time. The Discovery Client
Channel allows you to write a WCF client application, describe the service you want to call, and the client channel automatically sends a probe request. When a service responds, the discovery client channel retrieves the endpoint address for the service from
the probe response and uses it to call the service."