Research On Interworking Between SIP And ISUP In IMS Network

With the rapid advancement of technology and the increasing demand of customer, network architecher which can provide the overall multimedia services of speech, data and video with high quality is becoming the trend of development of telecommunication network. 3GPP (Third Generation Partnership Project) has bring up IMS (IP Multimedia core Subsystem) in version R5(release 5) to provide more plentiful multimedia services. Network convergence and interworking based on IMS has become hot spot for researching. Traditional circuit-swithed network will co-exist with packet-swithed network based on IMS for a long period because of technology and cost. Public Swithed Telephone Network (PSTN) is still the telecom and telephone network for interworking all over the world nowadays. It will be a big cost and waste if two networks access separately. Therefore, realizing to interwork between PSTN and IMS Network is very important. IMS is based on SIP (Session Initiation Protocol) procotol, and PSTN is controlled by ISUP (Integrated Service Digital Network User Part) protocol.One key point for interworking between IMS and PSTN is to realize the interworking between SIP and ISUP.This article is focus on researching, designing and realizing interworking between SIP and ISUP from the sight of network interworking based on IMS. It's main task is: 1. To research the frame and function entities of interworking between IMS and PSTN; 2. To analyze the type and format of message of SIP and ISUP, and the successful call procedure based on SIP and ISUP; 3. To research extensions to SIP for IMS; 4. To research message mapping between SIP and ISUP, including mapping of message type and mapping between ISUP parameters and SIP headers; 5. To design and realize MGCF (Media Gateway Control Function).