一、计算机网络的产生和演变 二、计算机网络的概念 三、计算机网络的功能 四、计算机网络的分类 五、计算机网络的术语

7.1 What is network security? 7.2 Principles of cryptography 7.3 Authentication 7.4 Integrity 7.5 Key Distribution and certification 7.6 Access control: firewalls 7.7 Attacks and counter measures 7.8 Security in many layers

《计算机网络与通讯》课程教学资源（PPT课件讲稿，英文版）Chapter 3 Transport Layer

IP datagram format IP protocol version 32 bits Imber total datagram header lenath lver/head pe length(bytes) (bytes) Hlen service

Assignment: read Part I: Introduction chapter 1 in text ur goa Overview: get contex↑ what's the Internet overview.\feel\of what's a protocol?

Chapter 7: Network security Foundations: what is security? crypfography authentication message integrity key distribution and certification Security in practice: application layer: secure e-mail

Network layer functions transport packet from sending to receiving hosts network layer protocols in physical every host, router data link physical data link

Summary of mac protocols What do you do with a shared media? Channel Partitioning by time, frequency or code Time Division, Code Division, Frequency Division Random partitioning dynamic

TCP segment structure 32 bits URG: urgent data (generally not used) source port #f dest port counting by bytes sequence number

Link Layer: setting the context actual PDu flow Router r1 applicatio pp lication transport trar sport network net vork data link