ZyXEL LTE5121 User Guide - Page 179
SIP Identities, SIP Number, SIP Service Domain, SIP Registration
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Chapter 17 VoIP 17.8 Technical Reference This section contains background material relevant to the VoIP screens. 17.8.1 VoIP VoIP is the sending of voice signals over Internet Protocol. This allows you to make phone calls and send faxes over the Internet at a fraction of the cost of using the traditional circuit-switched telephone network. You can also use servers to run telephone service applications like PBX services and voice mail. Internet Telephony Service Provider (ITSP) companies provide VoIP service. Circuit-switched telephone networks require 64 kilobits per second (Kbps) in each direction to handle a telephone call. VoIP can use advanced voice coding techniques with compression to reduce the required bandwidth. 17.8.2 SIP The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol that handles the setting up, altering and tearing down of voice and multimedia sessions over the Internet. SIP signaling is separate from the media for which it handles sessions. The media that is exchanged during the session can use a different path from that of the signaling. SIP handles telephone calls and can interface with traditional circuit-switched telephone networks. SIP Identities A SIP account uses an identity (sometimes referred to as a SIP address). A complete SIP identity is called a SIP URI (Uniform Resource Identifier). A SIP account's URI identifies the SIP account in a way similar to the way an e-mail address identifies an e-mail account. The format of a SIP identity is SIP-Number@SIP-Service-Domain. SIP Number The SIP number is the part of the SIP URI that comes before the "@" symbol. A SIP number can use letters like in an e-mail address ([email protected] for example) or numbers like a telephone number ([email protected] for example). SIP Service Domain The SIP service domain of the VoIP service provider is the domain name in a SIP URI. For example, if the SIP address is [email protected], then "VoIP-provider.com" is the SIP service domain. SIP Registration Each LTE Device is an individual SIP User Agent (UA). To provide voice service, it has a public IP address for SIP and RTP protocols to communicate with other servers. A SIP user agent has to register with the SIP registrar and must provide information about the users it represents, as well as its current IP address (for the routing of incoming SIP requests). LTE-5121 User's Guide 179