Network Deployment (Distributed operating systems), v8.0 > Develop and deploying applications > Develop SIP applications > Develop SIP applications > SIP servlets > JSR 289 overview

SIP application router

The SIP application router is used by the SIP container to select the order in which applications are run within the container.

The SIP container can invoke multiple applications in order to deploy a complete service or function. This modular and compositional approach makes it easier for application developers to develop new applications. The modular applications can be more easily combined and managed, while individual application implementations remain independent.

The application router is responsible for selecting the correct applications in the correct order to service an incoming message. An application router is required for a container to function, but it is a separate logical entity from the container. The application router is based on the JSR 289 specification. See the specification for more details about the application router function.

The default application router (DAR) can be configured with a standard configuration file, which is supplied to the container through a SIP container custom property, as defined in JSR 289. The DAR configuration file can also be uploaded in the admin console for each target of the DAR.

Application routing, also referred to as application composition, can be handled in a number of ways:

• Specify the order in which the applications should run using the administrative console.
• Upload a custom application router implementation class either by specifying the path of the Java archive (JAR) file containing the application router implementation and provider through the console or adding it to the class path. A specific provider can be defined with a SIP container custom property.

• Configure the DAR by uploading its properties file and providing its location through a system property.

• Use an interactive wizard to generate a DAR configuration file.

Restriction: WAS has a default way of sorting the order of SIP applications invocation using the Startup behavior settings. The sorting order is based on the application weight. This weighting policy only applies if you do not specify a DAR property file and no custom application router has been associated with the server or cluster. If CEA features are used, the CEA system application requires special consideration when enabled on the same server or cluster as a custom application router.

To deploy an application router and still maintain the capabilities of the CEA system application, use one of the following two options:

• Only enable CEA on an isolated server or cluster that includes no custom application router.

• Make sure the custom application router routes all CEA specific messages to the CEA system application.

  To do this, the developer of the application router must check the mappings that are defined in the sip.xml file associated with the CEA system application. The sip.xml file associated with the CEA system application can be found in the directory path at WAS_HOME/systemApps.

  The following information explains how to configure a custom application router to route to the commsvc system application. The examples show a custom application router configuration with and without the commsvc application.

  First, here is an example configuration without commsvc:

  INVITE: ("TestB2bua", "DAR:To", "NEUTRAL", "", "NO_ROUTE", "0")
  

  The first element after the INVITE is the display name of the test application, and this one-line application router routes b2bua calls to the application successfully. With the preceding application router configured on the SIP container, however, CEA Web collaboration attempts fail.

  To enable routing to the CEA system application, just clone the routing element and change the application name in the second element instance:

  INVITE: ("TestB2bua", "DAR:To", "NEUTRAL", "", "NO_ROUTE", "0"),("commsvc", "DAR:To", "NEUTRAL", "", "NO_ROUTE", "0")
  

  This action ensures that CEA messages are routed correctly.

Configure SIP application routers

Related

SIP application router collection
SIP application router settings

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