操作系统课件第六章.pptx

1、Nankai UniversityCopyright Xu Jingdong, All right reserved1Computer Networks reviewXu JingdongDept. of Computer Science and Information Security Nankai University Nankai UniversityCopyright Xu Jingdong, All right reserved2Chapter 1Internet overviewnetwork edge: client/server and peer-to-peer modelne

2、twork core: packet-switching versus circuit-switchingpacket-switchingstatistical multiplexingroutingend to end latencymessage and packetProtocol, layering and service modelsWhy layeringOSI reference model, TCP/IP modellogical communication, physical communicationNankai UniversityCopyright Xu Jingdon

3、g, All right reserved3Chapter 2Application service requirements:reliability, bandwidth, delayInternet transport service modelconnection-oriented, reliable: TCPunreliable, datagram: UDPClient-server, P2PFile Transfer Service and Protocol FTP Process ModelFTP commands and responsesConnection and Autho

4、rizationNankai UniversityCopyright Xu Jingdong, All right reserved4Chapter 2 (cont.)Web Service and ProtocolWeb Client/server ModeBrowser ArchitectureHTTP: HyperText Transfer Protocol-1.0 and 1.1Uniform Resource LocatorsHyperText Markup LanguageElectronic Mail Service and ProtocolMail Client/server

5、ModeSimple Mail Transfer ProtocolMail access protocols-POP3Mail Message Format-822 and MIMENankai UniversityCopyright Xu Jingdong, All right reserved5Chapter 2 (cont.)DNSFlat and Hierarchical NamespaceDNS Name SpaceName ResolutionResource Record StructureDNS Message FormatWiresharkNankai UniversityC

6、opyright Xu Jingdong, All right reserved6Chapter 3Transport layer servicesMultiplexing/demultiplexingConnectionless transport: UDPPrinciples of reliable data transferrdt1.0, rdt2.0, rdt2.1, rdt2.2, rdt3.0Performance of protocolstop-and-wait protocolpipelined protocols: Go-Back-N and Selective Repeat

7、Nankai UniversityCopyright Xu Jingdong, All right reserved7Chapter 3 (cont.)Connection-oriented transport: TCPreliable transfer seq. # and ACK # Timeouts and Retransmission, Fast Retransmit flow controlconnection managementTCP congestion controlcongestion windowslow startcongestion avoidance: Tahoe

8、and Renofast recoveryNankai UniversityCopyright Xu Jingdong, All right reserved8Chapter 4Internet protocol (IP)IP addressingIP datagram formatIP datagram forwardingIP Fragmentation & ReassemblyForwarding in an IP RouterSubnetting and CIDRNAT: Network Address TranslationInternet Control Message Proto

9、col (ICMP)Nankai UniversityCopyright Xu Jingdong, All right reserved9Chapter 4 (cont.)routing principleslink state algorithmsdistance vector algorithmshierarchical routingInternet routing protocolsintra-domain: RIP, OSPF Inter-domain: BGPNankai UniversityCopyright Xu Jingdong, All right reserved10Ch

10、apter 5Introduction of interface layer Broadcast vs. Switched Networks LAN architecture and Interface Layer functions Principles of interface layer Encoding and decoding Error detection Multiple access protocols: CSMA/CDLAN technologies LAN addressing: physical address Mapping IP address to physical address: ARP Shared Ethernet Switched Ethernet