Start Here to Learn About SIP!

The Session Initiation Protocol (SIP) is a signaling protocol that is used by technology products for creating session-oriented connections between two or more endpoints in an IP network. These endpoints could be IP telephones, instant messaging clients, or a collaborative multimedia conference application. The core protocol itself is defined within the IETF SIP working group. Additional work is done in the IETF SIPPING working group, which is chartered to document the use of SIP for several applications related to telephony and multimedia, and to develop requirements for extensions to SIP needed for those applications.

While the protocol is now "final" enough to build sophisticated telecom systems using SIP, the IETF working groups continue to forge new and novel concepts on how to apply SIP. You can explore some of these ideas in the SIP Internet Drafts summary on our site.

The SIP Forum is not a protocol creation body; our charter is to promote and advance the interoperability of products and services using SIP. However, in that context the Forum does assist the industry by specifying Recommendations on how industry vendors should select among choices available within the protocol itself in order to build and deploy products and services which are highly interoperable with each other.

White Papers

While technical readers may wish to begin with the IETF RFCs listed at the Working Group pages linked above, non-technical readers may want to take advantage of the White Papers on SIP and SIP-based technology many of our members have produced. While these are slightly on the technical side, they are definitely readable by mere mortals, and don't require deep engineering skills. These White Papers are a huge resource for people just learning about SIP. A brief summary about SIP is also available at the SIP Center.

Products and Services using SIP

No matter who you are, you can find a wide variety of standards-based SIP products and services for you to use in your application.

Generally, industry providers divide their products into the following categories, based on the type of customer and application involved: enterprise products, open source products and components, consumer services, service provider products, and development tools.

SIPconnect and the SIPconnect Compliant Certification Program

The SIPconnect Technical Recommendation is an industry-wide, standards-based approach to direct IP peering between SIP-enabled IP PBXs and VoIP service provider networks. The SIP Forum promotes the SIPconnect initiative to the IP Communications industry, and supplies all input for future versions.

The SIPconnect Compliant Certification Program is a vehicle through which eligible companies can license the use of the SIP Forum's 'SIPconnect Compliant' certification mark -- the official brand of the leading standard for SIP Trunking products and services.

Other Resources

There are also some additional links in the menu on the left that can guide you to other web-based resources about SIP.