第十一章 计算机网络第五版教学Chapter4---AriesHE-4.1-4.3.pptVIP

Chapter 4: Network Layer Chapter goals: understand principles behind network layer services: network layer service models网络层服务模型 forwarding versus routing转发与路由 how a router works路由器怎么工作的 routing (path selection)路由（路径选择） dealing with scale如何扩展 advanced topics: IPv6, mobility IPv6，移动IP Chapter 4: Network Layer 4. 1 Introduction 4.2 Virtual circuit and datagram networks 4.3 What’s inside a router 4.4 IP: Internet Protocol Datagram format IPv4 addressing ICMP IPv6 4.5 Routing algorithms Link state Distance Vector Hierarchical routing 4.6 Routing in the Internet RIP OSPF BGP 4.7 Broadcast and multicast routing Two Key Network-Layer Functions forwarding: move packets from router’s input to appropriate router output 转发：将报文从路由器的输入发送到合适的输出端口 routing: determine route taken by packets from source to dest. 路由：决定报文从源到目的的路径 routing algorithms路由算法 Connection setup连接建立 3rd important function in some network architectures:在一些网络架构里面，建立连接是继转发和路由后的第三大重要功能 ATM异步传输模式, frame relay帧中继, X.25 before datagrams flow, two end hosts and intervening routers establish virtual connection在数据报发送之前，两个端主机以及中间的路由器会建立一条虚拟连接 routers get involved路由器也包含其中 network vs transport layer connection service:网络层和传输层的连接服务 network: between two hosts (may also involve intervening routers in case of VCs)在两个主机之间建立连接 transport: between two processes在两个进程之间建立连接 Network service model网络服务模型 Example services for individual datagrams:对于单个报文 guaranteed delivery保证投递 guaranteed delivery with less than 40 msec delay保证投递时延迟少于40微秒 Example services for a flow of datagrams:对于报文流 in-order datagram delivery 报文按序投递 guaranteed minimum band-width to flow保证传输时的最小带宽 Chapter 4: Network Layer 4. 1 Introduction 4.2 Virtual circuit and datagram networks 4.3 What’s inside a router 4.4 IP: Internet Protocol Datagram format IPv4 addressing ICMP IPv6 4.5 Routing algorithms Link state Distance Vector Hierarchical routing 4.6 Routing in the Internet RIP OSPF BGP 4.7 Broadcast and multicast routing Network layer connection and connection-less