Glossary

The Session Initiation Protocol (SIP) is a signaling protocol for initiating, managing and terminating voice and video sessions across packet networks. Borrowing from Internet protocols, such as HTTP and SMTP, SIP is text-encoded and highly extensible. SIP can be extended to accommodate features and services such as call control services, mobility and interoperability with existing telephony systems.

SIP is being standardized by the SIP Working Group and others, within the Internet Engineering Task Force (IETF). The protocol is published as RFC 3261 and includes numerous extensions to the basic SIP Protocol.

SIP was designed by Schulzrinne and Handley starting in 1996. In November 2000 SIP was accepted as a 3GPP signaling protocol and permanent element of IMS for IP-based multimedia streaming in cellular systems. It is independent of the underlying transport layer, and so can run over TCP, UDP or SCTP.

SIP is an important VoIP protocol that is being widely used in today's communication networks. It also plays a key role in IMS/NGN networks.

RADVISION offers various SIP tools for developers:

• SIP stack, for developing any kind of a SIP product
• SIP server framework, for developing SIP servers
• Multimedia Terminal Framework, for developing SIP clients
• BEEHD, for developing videophones
• ProLab, for testing SIP products and networks