<!- - External mechanism- ->
<PolicyAttachment>
 <AppliesTo>
  <EndpointReference>
   <wsdl:service name="SettlementService>
  </EndpointReference>
 </AppliesTo>
 <Policy ReferenceURI="policies#PerformancePolicy" utility="float">
  <preCondition>
   <exchange:BusinessHours/>
  </preCondition>
 </PolicyReference>
</PolicyAttachment>
<!- - Embedded mechanism- ->
<wsdl:service name="SettlementService>
 <PolicyReference URI="policies#PerformancePolicy" utility="float">
  <preCondition>
   <exchange:BusinessHours/>
  </preCondition>
 </PolicyReference>
</wsdl:service>
Algorithm 3: Policy attachment mechanisms.