Optional Policy Assertions

There are behaviors that may be engaged for a Web service interaction. This service will not fault if these behaviors are not engaged.

Policy assertions can be marked optional to represent behaviors that may be engaged (capabilities) for an interaction. Optional marker is an attribute @wsp:Optional on a policy assertion element. In the example below, optimized MIME serialization is marked optional. That is, this policy expression requires the use of security and optimization, or only security.

<wsp:Policy>
  <sp:TransportBinding>
    ...
  </sp:TransportBinding>
  <mtom:OptimizedMimeSerialization @wsp:Optional=”true”/>
</wsp:Policy>