Design and Implementation of VoIP Gateway

• Main Authors: Jhih-Sin Chen, 陳志欣
• Other Authors: Chun-Hung Richard Lin
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/93556090625635290024

碩士 === 國立中山大學 === 資訊工程學系研究所 === 94 === With the bandwidth growing and voice coding technology enhancing, VoIP(Voice over IP)becomes a very popular application in recent years. Although VoIP has good voice quality and huge price advantage, it can''t replace PSTN(Public Switched Telephone Network) completely in the next few years. We therefore hope to be able to solve the connectivity issue between PSTN and VoIP. In this thesis, I design and implement a VoIP Gateway using Infineon EASY 5120 platform which has a powerful CPU with network processor, ADM5120, and has a DSP (Digital Signal Processor), Vinetic-2CPE PEB3332, to handle digital and analog voice signals. The operation method of the gateway is that PSTN analog signals are passed to Vinetic-2CPE from FXO (Foreign eXchange Office) port, and they are transferred into digital signals to be packetized to transit into Internet to another VoIP Client. My VoIP Gateway can solve the interconnection issues between PSTN and VoIP. Furthermore, in order to solve NAT traversal problem of SIP protocol, we propose and implement an integration approach which uses STUN (Simple Traversal of UDP through NAT) to cooperate with RTP Relay server to traverse various types of NAT, especial symmetric NAT. My VoIP Gateway not only can traverse any type of NAT but also can perform self-configuration according to STUN test report in various network environments.