With 35% new material, The IMS, IP Multimedia Concepts and Services, 3rd Edition has been completely revised to include updated chapters and an entirely new chapter on multimedia phone IMS and IMS voice call continuity. Additional new material includes transit IMS, IMS local numbering, emergency session, the identification of communication services in IMS, the authentication of new models for fixed access, NAT traversal and globally routable user agent URI. The main features of the 3rd edition: Two new chapters on IMS multimedia telephony service and IMS Voice Call Continuity Updated information on Third Generation Partnership Project (3GPP) Release 7 levels, including architecture, reference points and concepts substantially expand the area on detailed procedures IMS Completely rewritten and extended chapters on IMS services