Developing Applications with WebLogic SIP Server

Using Content Indirection in SIP Servlets

The following sections describe how to develop SIP Servlets that work with indirect content specified in the SIP message body:

Overview of Content Indirection

Data provided by the body of a SIP message can be included either directly in the SIP message body, or indirectly by specifying an HTTP URL and metadata that describes the URL content. Indirectly specifying the content of the message body is used primarily in the following scenarios:

When the message bodies include large volumes of data. In this case, content indirection can be used to transfer the data outside of the SIP network (using a separate connection or protocol).
For bandwidth-limited applications. In this case, content indirection provides enough metadata for the application to determine whether or not it should retrieve the message body (potentially degrading performance or response time).

WebLogic SIP Server provides a simple API that you can use to work with indirect content specified in SIP messages.

Using the Content Indirection API

The content indirection API provided by WebLogic SIP Server helps you quickly determine if a SIP message uses content indirection, and to easily retrieve all metadata associated with the indirect content. The basic API consists of a utility class, com.bea.wcp.sip.engine.server.ContentIndirectionUtil, and an interface for accessing content metadata, com.bea.wcp.sip.engine.server.ICParsedData.

SIP Servlets can use the utility class to identify SIP messages having indirect content, and to retrieve an ICParsedData object representing the content metadata. The ICParsedData object has simple “getter” methods that return metadata attributes.

Additional Information

Complete details about content indirection are available in a draft document: http://www.ietf.org/internet-drafts/draft-ietf-sip-content-indirect-mech-05.txt.

See also the WebLogic SIP Server JavaDoc for additional documentation about the content indirection API.