A Initial Filter Criteria

The following sections describe iFC configuration:

• Initial Filter Criteria Standard

• Configuring Initial Filter Criteria

• Basic Initial Filter Criteria Elements

Initial Filter Criteria Standard

iFC is an XML-based format used for describing an orchestration logic. iFC is specified in:

• ETSI TS 129 228 V7.11.0, IP Multimedia (IM) Subsystem Cx and Dx Interfaces

• 3GPP TS 29.328 V7.11.0, IP Multimedia Subsystem (IMS) Sh interface; Signalling flows and message contents, Release 7.

Configuring Initial Filter Criteria

You define iFC by specifying the parameters described in "Basic Initial Filter Criteria Elements" in an XML file. The following sample XML file defines an orchestration logic in the iFC format.

<InitialFilterCriteria>
   <Priority>1</Priority>
   <TriggerPoint>
      <ConditionTypeCNF>0</ConditionTypeCNF>
         <SPT>
            <ConditionNegated>0</ConditionNegated>
            <Group>0</Group>
            <Method>INVITE</Method>
         </SPT>
   </TriggerPoint>

   <ApplicationServer>
      <ServerName>sip:vpn@192.168.1.139:5060</ServerName>
      <DefaultHandling>0</DefaultHandling>
      <Extension>
         <ForceB2B/>
      </Extension>
   </ApplicationServer>
<InitialFilterCriteria>

For more information about XML schema of the iFC XML, see 3GPP TS 29.328 V7.11.0, IP Multimedia Subsystem (IMS) Sh interface; Signalling flows and message contents, Release 7.

Basic Initial Filter Criteria Elements

The main element in an orchestration logic iFC is named Initial Filter Criteria. An orchestration logic XML contains zero or several instances of the Initial Filter Criteria element. Each instance consists of zero or one instance of the Trigger Point element and one instance of the Application Server element. The Priority element indicates the priority of the Filter Criteria element.

The following sections explain each of these elements.

Priority

In some cases, conditions defined in several different filter criteria can be met. To enable the OE to choose a specific filter criteria, you can define a filter criteria's priority.

The higher the rule's priority number, the lower priority the filter criterion has. This means that a filter criterion with a higher value of priority number is assessed after the filter criteria with a smaller priority number has been assessed. 0 (zero) means the highest priority. 100 means the lowest priority.

The same priority cannot be assigned to more than one initial filter criterion.

Trigger Point

The Trigger Point element consists of one or more Service Point Triggers (SPTs). For each SPT, you must define the following parameters:

• SPT condition type, which defines how a set of STPs is expressed:

  • Conjunctive Normal Form (CNF), which is an ANDed set of ORed subsets. For example: (SPT1 OR SPT2 OR SPT3) AND (SPT4 OR SPT5)

  • Disjunctive Normal Form (DNF), which is an ORed set of ANDed subsets. For example, (SPT1 AND SPT2 AND SPT3) OR (SPT4 AND SPT5)

• ConditionNegated, which defines whether or not the condition must be negated

• Group, which defines a group to which the SPT belongs

• Method, which defines a SIP method used to initiate a call

Application Server

The Application Server element defines the application server that contacts, if the trigger point is met. The Application Server element consists of the following elements:

• <ServerName>, which defines a SIP URL of an application server to which Service Broker routes a session

• <Default Handling>, which defines whether or not Service Broker releases a session if an application server cannot be reached. You can set <Default Handling> to one of the following values:

  • 0, to instruct Service Broker to continue a session

  • 1, to instruct Service Broker to terminate a session

• <Extension> (optional), which may contain the <ForceB2B> element. In this case, when the OE receives a response from an application, it sends an INVITE message to a next application server as defined in the orchestration logic, instead of returning this response to the network entity.