现代交换技术英文版chpter 1-3.pptVIP

Modern Switching Technology现代交换技术 This course introduces the information switching technology spending 28 periods Textbook and reference book 《现代电信交换与网络》英文版《Telecommunication Switching Systems and Networks》。Thiagarajan Viswanathan。电子工业出版社，2009.1 《现代交换原理》第2版。金惠文等。电子工业出版社，2005.4，21世纪高等学校电子信息类教材 《现代交换技术》第2版。张中奎 。 人民邮电出版社2009.3 Chapter 1 prolegomena Switching and communication network The classification of switching technology and its evolution. Constitute of switching device §1.1 Switching and communication network The full-interconnected network is the most reliable and no-blocking. Switched network maybe present blocking. Switched network is more economical than full-interconnected one. For example, if there are 100 subscribers, the switched network needs 100 cables; the full-interconnected network needs 4950 (100×99÷2=4950) cables. Present networks are switched networks. Conclusion The switching device is the important component of the communication network. The capability of network depends on the capability of switching device. Chapter 1 prolegomena Switching and communication network The classification of switching technology and its evolution. Constitute of switching device §1.3 The classification of switching technology and its evolution communication network evolution 一、 circuit switching——used in telephone network Channel is established before communication, used only by a pair of subscribers, and released when communication is over. Real time The rate of channel utilization is low. Establish logical connection before communication Packets are transmitted to destination along the logical connection in sequence The logical path is shared by many subscribers. 四、 ATM Asynchronous Transfer Mode异步转移模式 It can be seen as a combination of packet switching and circuit switching. The message is divided into fixed-length cell to store and forward. Connection-oriented, virtual connection. ATM has been used in backbone communication network. 五、 multi-