This chapter describes how to manage back-to-back user agents (B2BUAs) in Oracle Communications Converged Application Server.

A B2BUA is a Session Initiation Protocol (SIP) element that acts as an endpoint for two or more dialogs and forwards requests and responses between those two dialogs in some fashion.

B2BUAs are sometimes considered undesirable because of their potential to break services. That potential stems from the fact that they sit between two endpoints and, in some way, mediate the signaling between those endpoints. If the B2BUA doesn't know about an end-to-end service being used between those two endpoints, it may inadvertently break it.

B2BUAs are, however, an important tool for SIP application developers and as such are supported by the SIP Servlet application program interface (API). Oracle Converged Application Server supports a new helper class and some new methods to facilitate implementing B2BUAs as defined by Java Specification Request (JSR) 359, https://jcp.org/en/jsr/detail?id=359.