Discovery Proxy: This space left intentionally blank

WS-Discovery defines how a Client should switch from multicast behavior if there is a Discovery Proxy, but WS-Discovery does not define the protocol for talking to a Discovery Proxy; the intention is to allow WS-Discovery to compose with other, existing or new, registry-like protocols.

For example, either UDDI and LDAP would be credible protocols for a Discovery Proxy. If a UDDI server were acting as a Discovery Proxy, it would send a WS-Discovery Hello in response to any multicast Probe or Resolve. The Hello would include d:DiscoveryProxy in Types as well as something to indicate that it understands UDDI too, e.g., UddiV3:UDDI_Inquiry_PortType.

<s:Envelope>
  <s:Header>
    <a:Action>
        http://schemas.xmlsoap.org/ws/2004/02/discovery/Hello
    </a:Action>
    ...
  </s:Header>
  <s:Body>
    <s:Hello>
      <a:EndpointReference>
        <a:Address>
            http://uddi.dayton.corp.example.com
        </a:Address>
      </a:EndpointReference>
      <d:Types>
          d:DiscoveryProxy
          d:TargetService
          UddiV3:UDDI_Inquiry_PortType
      </d:Types>
      <d:MetadataVersion>76882</d:MetadataVersion>
    </s:Hello>
  </s:Body>
</s:Envelope>

A Client receiving the above Hello would know:

• It should not send multicast Probe or Resolve messages
• It may communicate with the Discovery Proxy at the provided EPR (in italics above) using messages indicated by UddiV3:UDDI_Inquiry_PortType