TCP_IP协议2.ppt

1、Introduction to TCP/IP Protocol Suite,Wu Peng Electronics & Information College,Outline,Whats a protocol? TCP/IP layering OSI & TCP/IP Reference Model Summary,Key words,Protocol n. 协议 Suite n. 组、套、族 Layering n. 分层,Router n. 路由器 Maintenance n. 维护 Modularization n. 模块化,a human protocol and a computer

2、network protocol:,Hi,Hi,TCP connection req,1 Whats a protocol（协议）?,We can regard all kind protocols as rules or regulations.,1 Whats a protocol （协议）?,human protocols: “whats the time?” “I have a question” introductions If specific msgs are sent specific actions will be taken when these msgs are rece

3、ived, or emerge other events,network protocols: machines rather than humans, all communication activities in Internet are governed by protocols,protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, reception,Protocol Layering（分层）,Netw

4、orks are complex! many “Components”: hosts routers links of various media applications protocols hardware, software,Question: Is there any hope of organizing structure of network? Or at least our discussion of networks?,Layering of airline functionality,Layers: each layer implements a service Each l

5、ayer has its own internal-layer actions Each layer relies on services provided by layer below,a series of steps,Why layering?,Dealing with complex systems: explicit structure allows identification to relationship of complex systems pieces layered reference model for discussion modularization eases m

6、aintenance, updating of system change of implementation of layers service transparent to rest of system e.g., change in gate procedure doesnt affect rest of system,2 TCP/IP layering,2 TCP/IP layering,Link Layer (data-link or network interface layer): includes device driver and network interface card

7、, handle hardware details of physically interfacing with the cable. Network Layer (internet layer): handles the movement of packets, i.e. Routing Transport Layer : provides a reliable flow of data between two hosts Application Layer : handles the details of the particular application, i.e. Email, FT

8、P,Example 1:Two hosts on a LAN,Example 2:Two networks connected with a router,TCP/IP Protocol Suite,Application layer are normally user processes. TCP and UDP are the two predominant transport layer protocols. Both use IP as the network layer.,TCP/IP Protocol Suite,TCP provides a reliable transport

9、layer while UDP is unreliable. UDP sends and receives datagrams for application, a datagram is a unit of information that travels from the sender to the receiver.,TCP/IP Protocol Suite,IP is the main protocol at the network layer. Every piece of TCP and UDP data that goes through the IP layer. There

10、 are other two protocols affiliate to IP at he network layer: ICMP and IGMP .,TCP/IP Protocol Suite,ARP(Address Resolution Protocol): IP to MAC address RARP(Reverse Address Resolution Protocol): MAC to IP address,3 OSI and TCP/IP reference model,OSI vs TCP/IP Reference Models,OSI introduced concept

11、of services, interface, protocols. These were force-fitted to TCP later. It is not easy to replace protocols in TCP OSI: reference model was done before protocols. TCP: protocols were done before the model OSI: Standardize first, build later TCP: Build first, standardize later OSI took too long to s

12、tandardize. TCP/IP was already in wide use by the time OSI become too complex,Problems of TCP/IP,Service, interface, and protocol not distinguished Host-to-network “layer” not really a layer No mention of physical and data link layers TCP/IP is not general and very suitable to the Internet.,Summary,Class objectives: Whats TCP/IP protocol suite Why layering Reference Models Key conc