The Design And Implementation Of SIP-Trunk System

With the development of data communications technology, more and morecompanies started to build IP-based internal telephone network. Internal telephonenetwork need to connect with external telephone network held by internet operater.SIP-Trunk is born in order to meet this demand.SIP-Trunk is a SIP-based system. The emergence of SIP-Trunk allows businesses toconnect with external telephone network only by deploying SIP phones and not need tohave a traditional analog telephone network. Internal communications within theenterprise is accomplished by IP telephony network only. All business communications tothe outside go through SIP Trunk to the ITSP, and then through the ITSP signaling/mediagateways to reach the PSTN. The enterprise only needs to maintain a single IP network toconnect to the local PSTN network, saving hardware and maintenance costs.This paper analyzes the SIP-Trunk system to achieve the main functions, anddescribes the processes required to perform these functions. This article describes theSIP-Trunk system to achieve account management, server group management, B2BUA,dial-up strategy, media streaming relay and other basic functions.This paper also analyzes some extended features of SIP-Trunk system. Theseextensions include the registration function, roaming call features, local survivabilityfunctionality. These extensions make SIP-Trunk system more comprehensive, expandedSIP-Trunk system applications.