26
CSCI-235 CSCI-235 Micro-Computer Micro-Computer Applications Applications The Network The Network

CSCI-235 Micro-Computer Applications The Network

Embed Size (px)

Citation preview

Page 1: CSCI-235 Micro-Computer Applications The Network

CSCI-235CSCI-235Micro-Computer ApplicationsMicro-Computer Applications

The NetworkThe Network

Page 2: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Network FundamentalsNetwork Fundamentals A computer A computer networknetwork consists of consists of

two or more computers linked two or more computers linked together to exchange data and together to exchange data and share resourcesshare resources

CommunicationCommunication is the process is the process of sending and receiving of sending and receiving messagesmessages

Communication channelsCommunication channels are are the paths through which the paths through which messages are passedmessages are passed

Communication devicesCommunication devices transform electronic signals transform electronic signals

Page 3: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Putting Together a NetworkPutting Together a Network

Basic ComponentsBasic Components Sending deviceSending device Communications linkCommunications link Receiving deviceReceiving device

Page 4: CSCI-235 Micro-Computer Applications The Network

A Communications ModelA Communications Model

SourceSource generates data to be transmittedgenerates data to be transmitted

TransmitterTransmitter Converts data into transmittable signalsConverts data into transmittable signals

Transmission SystemTransmission System Carries dataCarries data

ReceiverReceiver Converts received signal into dataConverts received signal into data

DestinationDestination Takes incoming dataTakes incoming data

Page 5: CSCI-235 Micro-Computer Applications The Network

Simplified Communications Simplified Communications Model - DiagramModel - Diagram

Page 6: CSCI-235 Micro-Computer Applications The Network

Simplified Data Simplified Data Communications ModelCommunications Model

Page 7: CSCI-235 Micro-Computer Applications The Network

Continuous & Discrete SignalsContinuous & Discrete Signals

Page 8: CSCI-235 Micro-Computer Applications The Network

Frequency Domain ConceptsFrequency Domain Concepts

Signal usually made up of many Signal usually made up of many frequenciesfrequencies

Components are sine wavesComponents are sine waves Can be shown (Can be shown (Fourier analysisFourier analysis) that any ) that any

signal is made up of component sine signal is made up of component sine waveswaves

Can plot frequency domain functionsCan plot frequency domain functions

Page 9: CSCI-235 Micro-Computer Applications The Network

Addition of Frequency Addition of Frequency ComponentsComponents

Page 10: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Data Rate and BandwidthData Rate and Bandwidth

Any transmission system has a limited Any transmission system has a limited band of frequenciesband of frequencies

This limits the This limits the data ratedata rate that can be carried that can be carried

Page 11: CSCI-235 Micro-Computer Applications The Network

BandwidthBandwidth BandwidthBandwidth is usually used to refer to the data is usually used to refer to the data

rate (i.e., the amount of data that can be rate (i.e., the amount of data that can be transmitted through a communications transmitted through a communications channel)channel)

Digital bandwidth is measured in bits per Digital bandwidth is measured in bits per second (bps), kilobits per second (Kbps), second (bps), kilobits per second (Kbps), megabits per second (Mbps), or gigabits per megabits per second (Mbps), or gigabits per second (Gbps)second (Gbps)

Low bandwidth is 56 Kbps and high bandwidth Low bandwidth is 56 Kbps and high bandwidth is 622 Mbpsis 622 Mbps

Page 12: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Modulation

DigitalAnalog

Analog Digital

Demodulation

Modems: From Digital to Analog Modems: From Digital to Analog and Backand Back

ModemsModems are devices that transform signals when are devices that transform signals when sending and receiving transmissionssending and receiving transmissions ModulationModulation – Transforming digital signals to analog – Transforming digital signals to analog DemodulationDemodulation – Transforming analog signals to digital – Transforming analog signals to digital

Page 13: CSCI-235 Micro-Computer Applications The Network

NetworkingNetworking

Point to point communication not usually Point to point communication not usually practicalpractical Devices are too far apartDevices are too far apart Large set of devices would need impractical Large set of devices would need impractical

number of connectionsnumber of connections Solution is a communications networkSolution is a communications network

Page 14: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Circuit switchingCircuit switching Networks create an end-Networks create an end-

to-end circuit between the to-end circuit between the sending and receiving sending and receiving computerscomputers

Electronic switches Electronic switches establish and maintain establish and maintain the connectionthe connection

Switching and Routing TechniquesSwitching and Routing TechniquesPacket switchingPacket switching

Outgoing messages are Outgoing messages are divided into fixed-size divided into fixed-size data units called data units called packetspackets

Packets are numbered Packets are numbered and addressed to the and addressed to the receiving computerreceiving computer

Routers examine the Routers examine the packets and send them to packets and send them to

their destinationtheir destination

Page 15: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

AdvantagesAdvantages DisadvantagesDisadvantages

CircuitCircuit switchingswitchingVoice and real-time Voice and real-time transmissiontransmission

No delivery delaysNo delivery delays

CostlyCostly

A direct electrical A direct electrical connection between connection between the computers is the computers is requiredrequired

Packet switchingPacket switching

Efficient, less Efficient, less expensive, and expensive, and reliablereliable

Will function if part Will function if part of the network is of the network is downdown

Delays in receiving Delays in receiving packetspackets

Not ideal for real-Not ideal for real-time voice time voice communicationcommunication

Advantages and Disadvantages Advantages and Disadvantages of Circuit and Packet Switchingof Circuit and Packet Switching

Page 16: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

ProtocolsProtocolsProtocolsProtocols are fixed, formalized standards are fixed, formalized standards

that specify how computers can that specify how computers can communicate over a networkcommunicate over a network

Page 17: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Network LayersNetwork Layers

Network architecture is the overall design of a networkNetwork architecture is the overall design of a network The network design is divided into layers, each of which The network design is divided into layers, each of which

has a function separate from that of the other layershas a function separate from that of the other layers Protocol stackProtocol stack – The vertical (top to bottom) arrangement – The vertical (top to bottom) arrangement

of the layers; each layer is governed by its own set of of the layers; each layer is governed by its own set of protocolsprotocols

user

physical media

user

physical media

receiving

sending

protocol

layerstack

Page 18: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Reduced hardware costsReduced hardware costs

Users share equipmentUsers share equipment

Connected peopleConnected people People can work People can work

together without being together without being at the same locationat the same location

Groupware enables Groupware enables sharing of schedules sharing of schedules and communicationsand communications

Advantages of NetworkingAdvantages of Networking

Shared applicationsShared applications Users share softwareUsers share software File server enables all File server enables all

users to work with the users to work with the same application program same application program

Building information Building information resourcesresources

Users create common Users create common pools of data that can be pools of data that can be accessed by employeesaccessed by employees

Page 19: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Local Area Network Local Area Network (LAN)(LAN)

Links computers within a Links computers within a building or group of building or group of buildingsbuildings

Uses direct cables, radio, Uses direct cables, radio, or infrared signalsor infrared signals

Types of Computer NetworksTypes of Computer Networks

Wide Area Network Wide Area Network (WAN)(WAN)

Links computers separated Links computers separated by a few miles or by a few miles or thousands of milesthousands of miles

Uses long-distance Uses long-distance transmission mediatransmission media

Page 20: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Local Area Networks (LANs)Local Area Networks (LANs) Network access is controlled by a network Network access is controlled by a network

administratoradministrator

Users can access software, data, and Users can access software, data, and peripheralsperipherals

LANs require special hardware and softwareLANs require special hardware and software

Computers connected to a LAN are called Computers connected to a LAN are called workstations workstations or or nodesnodes

Page 21: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

LAN Hardware and SoftwareLAN Hardware and Software

Networking HardwareNetworking HardwareNetwork interface card Network interface card

(NIC)(NIC) – Provides the – Provides the connection between the connection between the computer and the networkcomputer and the network

Inserted into a computer’s Inserted into a computer’s expansion slotexpansion slot

Networking SoftwareNetworking SoftwareOperating system that Operating system that

supports networking supports networking (Unix, Linux, Windows, (Unix, Linux, Windows, Mac OS)Mac OS)

Additional system Additional system softwaresoftware

NIC

Page 22: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Peer-to-Peer NetworksPeer-to-Peer Networks

All computers on the network are treated as equalAll computers on the network are treated as equalUsers decide which files and peripherals to shareUsers decide which files and peripherals to sharePeer-to peer is not suited for networks with many Peer-to peer is not suited for networks with many

computerscomputersPeer-to-peer is easy to set up. Example: home networksPeer-to-peer is easy to set up. Example: home networks

Page 23: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Client-Server NetworksClient-Server Networks

Typical corporate networks are Typical corporate networks are client-serverclient-server

Clients send requests to servers for programs Clients send requests to servers for programs and data, and to access peripheralsand data, and to access peripherals

Page 24: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

Wide Area Networks (WANs)Wide Area Networks (WANs)

WANsWANs are similar to long-distance are similar to long-distance telephone systemstelephone systems

Page 25: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

WAN ApplicationsWAN Applications

LAN-to-LANLAN-to-LAN WANs are used to connect LANs at two or WANs are used to connect LANs at two or

more geographic locationsmore geographic locations

Companies use WANs to connect their Companies use WANs to connect their branches to one network systembranches to one network system

Page 26: CSCI-235 Micro-Computer Applications The Network

© Prentice-Hall, Inc

BackbonesBackbones

BackbonesBackbones, high-capacity transmission lines, , high-capacity transmission lines, are regional, continental, or transcontinentalare regional, continental, or transcontinental

Internet backbones can carry 2.5 gigabits of Internet backbones can carry 2.5 gigabits of data per seconddata per second