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

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

3.1 运用实现原则的例子:更新TCAM 3.2 算法VS算法学:安全物证问题 3.3 十五条实现原则 3.4 需要注意的问题

《网络工程师考试同步辅导》教学资源（参考资料）第2章 数据通信基础

• 数据通信系统 • 基本概念 • 传输介质 • 数据编码 • 多路复用技术 • 数据交换技术 • 差错控制 • 数据通信性能指标

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

1建设目标 2需求分析 3校园网系统集成方案的规划设计 4校园网应用系统的集成实现 5校园网系统集成的特点分析

8.1 What is network security? 8.2 Principles of cryptography 8.3 Message integrity and Digital Signature 8.4 End point authentication 8.5 Securing e-mail 8.6 Securing TCP connections: SSL 8.7 Network layer security: IPsec 8.8 Securing wireless LANs 8.9 Operational security: firewalls and IDS

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

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