SOA Ecosystem–Interconnected Principles, Patterns, and Frameworks - Applied SOA Patterns on the Oracle Platform - page 54

<Policy wsu:Id="common">
<wsap:UsingAddressing />
....
<!-- other policies with usage attributes :
wsp:Optional="true" -->
</Policy>
The representation Policy to the service consumers is designed by binding policy ex-
pressions to WSDL elements, to service operation, for example as shown in the following
code:
<wsdl:binding name="AddressingBinding"
type="tns:RealTimeDataInterface" >
<PolicyReference URI="#common" />
<wsdl:operation name="getCargoStatus"
>...</wsdl:operation>
...
</wsdl:binding>
The last standards, presented as optional for all lanes are related to complex event pro-
cessing specifications: WS-Notifications (OASIS) and WS-Eventing (W3C). In a nutshell,
both of them describe the publish-subscribe protocols with the propagation of events that
follow right from the publisher to the subscriber, some sort of fire-and-forget messaging
patterns. It is important to remember that both subscribers and consumers are not always
the same actors; most interestingly, for Brokered Notification, some form of Service
Broker called Event Broker will be employed for distributing events between multiple
consumers.