A complete guide to designing and implementing SIP-based IP communication services The Session Initiation Protocol (SIP) is about to revolutionize telecommunications. This exciting protocol can be used to establish voice, video, and data sessions on the Internet, making a separate network for voice no longer necessary. The integration of voice with all other Internet services provides the greatest opportunity for innovation. Written by the authors who contributed to the development of the protocol and carrier class services based on SIP, this book explores what SIP does and the new services it enables. You ll find a critical assessment and detailed look at how IP communications based on SIP will enrich communication on the Internet. Sinnreich and Johnston also provide you with a better understanding of how SIP can be used with several key features of legacy telephony networks such as SS7 and ISDN signaling and for H.323 networks. Softswitch solutions are also discussed. They clearly explain the multiple design and implementation issues as well as the decisions you ll have to make in order to provide SIP-based IP communication services. Reflecting the latest developments by the IETF, this book covers: SIP-enabled communications, multimedia, and conferencing Elements of an SIP network, including user agents, servers, and location services Basics of SIP Security such as authentication, encryption, digital signatures, and firewalls Future services for SIP