Chapter 1 Introduction overview Computer networks consist of 1 Physical connections Cable, optical fiber, radio channel 2.Communication protocols: Defining the format, timing of signals/packets at different layers Different protocols make different network systems 3、 Applications: Client/server programs for different services www.gxmu.eau.cnwww.gxmu.edu.cn Computer networks consist of 1、Physical connections: • Cable, optical fiber, radio channel. 2、Communication protocols: • Defining the format, timing of signals/packets at different layers. • Different protocols make different network systems. 3、Applications: • Client/server programs for different services. Chapter 1 Introduction overview