Product Overview1Product OverviewThis chapter contains the following information about Skype for Business phones: VoIP Principle SIP Components Phone ModelsVoIP PrincipleVoIPVoIP (Voice over Internet Protocol) is a technology using the Internet Protocol instead oftraditional Public Switch Telephone Network (PSTN) technology for voice communications.It is a family of technologies, methodologies, communication protocols, and transmissiontechniques for the delivery of voice communications and multimedia sessions over IP networks.The H.323 and Session Initiation Protocol (SIP) are two popular VoIP protocols that are found inwidespread implementation.H.323H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T)that defines the protocols to provide audio-visual communication sessions on any packetnetwork. The H.323 standard addresses call signaling and control, multimedia transport andcontrol, and bandwidth control for point-to-point and multi-point conferences.It is widely implemented by voice and video conference equipment manufacturers, is usedwithin various Internet real-time applications such as GnuGK and NetMeeting and is widelydeployed by service providers and enterprises for both voice and video services over IPnetworks.SIPSIP (Session Initiation Protocol) is the Internet Engineering Task Force’s (IETF’s) standard formultimedia conferencing over IP. It is an ASCII-based, application-layer control protocol(defined in RFC 3261) that can be used to establish, maintain, and terminate calls between twoor more endpoints. Like other VoIP protocols, SIP is designed to address functions of signalingand session management within a packet telephony network. Signaling allows call informationto be carried across network boundaries. Session management provides the ability to controlattributes of an end-to-end call.
