Implementation Techniques For High-performance SIP Proxy Components: Transactions
01 January 2006
Session Initiation Protocol (SIP) proxies can process requests in transaction stateful or transaction stateless mode. The former maintains information to support a reliable exchange of messages. It keeps track of SIP requests with adjacent SIP elements. In contrast, a stateless proxy does not store information about requests received or forwarded to tis neighbors. SIP specification allows proxies to process some requests in transaction stateful mode, while the remaining requests in transaction stateless mode. In this paper, we present the main conceptual and implementation differences between stateful and stateless SIP proxies. We include some preliminary calculation that shows the benefit of stateless mode over stateful mode. We also include additional recommendations to build 3G Partnership Project (3GPP) IP Multimedia Subsystem (IMS) proxies, such as P-, I-, and S-CSCF.
