Proyek Sistem Operasi Proyek Sistem Operasi (Networking)(Networking)Chapter 14

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Distributed CapabilitiesDistributed CapabilitiesCommunications architectures

◦Software that supports a group of networked computers

Network operating system◦Each computer has its own private

operating systemDistributed operating system

◦Common operating system shared by a network of computers

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The Need for a Protocol The Need for a Protocol ArchitectureArchitectureComputer communications

◦Exchange of information between computers for the purpose of cooperative action

Computer network◦When tow or more computers are

interconnected via a communication network

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Two ConceptsTwo ConceptsProtocol

◦Used for communication between entities in different systems

Protocol architecture◦Broken into subtasks, each of which

is implemented separately

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File TransferFile Transfer

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The TCP/IP Protocol The TCP/IP Protocol ArchitectureArchitectureProtocol suiteFive relatively independent

layers◦Physical◦Network access◦Internet◦Host-to-host, or transport◦Application

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Physical LayerPhysical LayerSpecifying

◦the characteristics of the transmission medium

◦Nature of the signals◦Data rate

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Network Access LayerNetwork Access LayerConcerned with the exchange of

data between an end system and the network

Different standards◦Circuit switching◦Packet switching (frame relay)◦LANs (Ethernet)

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Internet LayerInternet LayerProcedures for data to traverse

different networksImplemented in the end systems

and routers

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Transport LayerTransport LayerEnsures all data arrives at the

destination and in the order sentTCP

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Application LayerApplication LayerSupports various user applicationExample: file transfer

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TCP HeaderTCP Header

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UDPUDP

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IPIP

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IPv6IPv6Provides enhancements over

existing IPDesigned to accommodate

higher speeds of a mix of data streams, graphic and video

Provides more addressesIncludes 128-bits for addresses

◦IP uses 32-bit address

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IPv6IPv6

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TCP/IP ConceptsTCP/IP Concepts

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Protocols and HeadersProtocols and Headers

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Items in the HeaderItems in the HeaderDestination network addressFacilities requests

◦Example: priority

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TCP.IP ApplicationsTCP.IP ApplicationsSimple Mail Transfer Protocol

(SMTP)File Transfer ProtocolTELNET

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SocketsSocketsEnable communication between

a client and serverConcatenation of a port value

and an IP address form a socket

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Two Types of SocketsTwo Types of SocketsStream sockets

◦Use TCP◦Reliable data transfer

Datagram sockets◦Use UDP◦Delivery is not guaranteed

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Socket SetupSocket Setupsocket() commandThree parameters

◦Protocol family is always PF_INET for TCP/IP

◦Type specifies whether stream or datagram

◦Protocol specifies either TCP or UDP

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