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Computer Network Basic concept
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Introduction Introduction to to
Computer AdministrationComputer Administration
Computer Network - Computer Network - Basic ConceptsBasic Concepts
Computer NetworksComputer Networks Communication ModelCommunication Model Transmission ModesTransmission Modes Communication TypesCommunication Types Classification Of Computer Networks Classification Of Computer Networks
By ScaleBy Scale By StructureBy Structure By TopologyBy Topology
Network MediaNetwork Media InternetworkingInternetworking
Computer NetworkComputer Network
A computer network is a group of interconnected A computer network is a group of interconnected computers.computers.
It allows computers to communicate with each It allows computers to communicate with each other and to share resources and information. other and to share resources and information.
First Network : The Advanced Research Projects First Network : The Advanced Research Projects Agency (ARPA) funded the design of the "Advanced Agency (ARPA) funded the design of the "Advanced Research Projects Agency Network" (ARPANET) for Research Projects Agency Network" (ARPANET) for the United States Department of Defensethe United States Department of Defense
Communication ModelCommunication Model
Communication ModelCommunication 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
Communication ModelCommunication Model
Transmission ModesTransmission Modes SimplexSimplex
One directionOne direction e.g. Televisione.g. Television
Half duplexHalf duplex Either direction, but Either direction, but
only one way at a only one way at a timetime
e.g. police radioe.g. police radio
Full duplexFull duplex Both directions at Both directions at
the same timethe same time e.g. telephonee.g. telephone
Communication TypesCommunication Types
Unicasting (one-to-one)Unicasting (one-to-one)
Multicasting (one-to-many)Multicasting (one-to-many)
Broadcasting (one-to-all)Broadcasting (one-to-all)
Network ClassificationNetwork Classification
By Size or ScaleBy Size or Scale LANLAN WANWAN MANMAN CANCAN PANPAN
Local Area Network (LAN)Local Area Network (LAN)
Contains printers, servers and Contains printers, servers and computerscomputers
Systems are close to each otherSystems are close to each other Contained in one office or buildingContained in one office or building Organizations often have several Organizations often have several
LANSLANS
Wide Area Networks (WAN)Wide Area Networks (WAN)
Two or more LANs connectedTwo or more LANs connected Over a large geographic areaOver a large geographic area Typically use public or leased linesTypically use public or leased lines
Phone linesPhone lines SatelliteSatellite
The Internet is a WANThe Internet is a WAN
Metropolitan Area Network Metropolitan Area Network (MAN)(MAN)
Large network that connects Large network that connects different organizationsdifferent organizations
Shares regional resourcesShares regional resources A network provider sells timeA network provider sells time
Campus Area Networks Campus Area Networks (CAN)(CAN)
A LAN in one large geographic areaA LAN in one large geographic area Resources related to the same Resources related to the same
organizationorganization Each department shares the LANEach department shares the LAN
Personal Area Network Personal Area Network (PAN)(PAN)
Very small scale networkVery small scale network Range is less than 2 metersRange is less than 2 meters Cell phones, PDAs, MP3 playersCell phones, PDAs, MP3 players
Network ClassificationNetwork Classification
By Structure / Functional By Structure / Functional RelationshipRelationship Client / ServerClient / Server Peer to Peer (P2PN)Peer to Peer (P2PN)
Client/Server networkClient/Server network
Nodes and servers share data rolesNodes and servers share data roles Nodes are called clientsNodes are called clients Servers are used to control accessServers are used to control access Database softwareDatabase software
Access to data controlled by serverAccess to data controlled by server Server is the most important Server is the most important
computercomputer
Peer to peer networks Peer to peer networks (P2PN)(P2PN)
All nodes are equalAll nodes are equal Nodes access resources on other Nodes access resources on other
nodesnodes Each node controls its own resourcesEach node controls its own resources Most modern OS allow P2PNMost modern OS allow P2PN Distributed computing is a formDistributed computing is a form KazaaKazaa
Network ClassificationNetwork Classification
By Topology / Physical ConnectivityBy Topology / Physical Connectivity BUSBUS STARSTAR RINGRING MESHMESH TREETREE
Network TopologyNetwork Topology
Logical layout of wires and equipmentLogical layout of wires and equipment Choice affects Choice affects
Network performanceNetwork performance Network sizeNetwork size Network collision detectionNetwork collision detection
BUSBUS Also called linear busAlso called linear bus
One wire connects all nodesOne wire connects all nodes
Terminator ends the wiresTerminator ends the wires
AdvantagesAdvantages Easy to setupEasy to setup Small amount of wireSmall amount of wire
DisadvantagesDisadvantages SlowSlow Easy to crashEasy to crash
STARSTAR All nodes connect to a hubAll nodes connect to a hub
Packets sent to hubPackets sent to hub Hub sends packet to destinationHub sends packet to destination
AdvantagesAdvantages Easy to setupEasy to setup One cable can not crash networkOne cable can not crash network
DisadvantagesDisadvantages One hub crashing downs entire One hub crashing downs entire
networknetwork Uses lots of cableUses lots of cable
Most common topologyMost common topology
RINGRING
Nodes connected in a circleNodes connected in a circle
Tokens used to transmit dataTokens used to transmit data Nodes must wait for token to sendNodes must wait for token to send
AdvantagesAdvantages Time to send data is knownTime to send data is known No data collisionsNo data collisions
DisadvantagesDisadvantages SlowSlow Lots of cableLots of cable
MESHMESH All computers connected togetherAll computers connected together
Internet is a mesh networkInternet is a mesh network
AdvantageAdvantage Data will always be deliveredData will always be delivered
DisadvantagesDisadvantages Lots of cableLots of cable Hard to setupHard to setup
TREETREE
Hierarchal ModelHierarchal Model
AdvantagesAdvantages ScaleableScaleable Easy ImplementationEasy Implementation Easy TroubleshootingEasy Troubleshooting
Network MediaNetwork Media
Links that connect nodesLinks that connect nodes Choice impactsChoice impacts
SpeedSpeed SecuritySecurity SizeSize
Twisted-pair cablingTwisted-pair cabling
Most common LAN cableMost common LAN cable
Called Cat5 or 100BaseTCalled Cat5 or 100BaseT
Four pairs of copper cable twistedFour pairs of copper cable twisted
May be shielded from interferenceMay be shielded from interference
Speeds range from Speeds range from 1 Mbps to 1,000 Mbps1 Mbps to 1,000 Mbps
Coaxial cableCoaxial cable
Similar to cable TV wireSimilar to cable TV wire
One wire runs through cableOne wire runs through cable
Shielded from interferenceShielded from interference
Speeds up to 10 MbpsSpeeds up to 10 Mbps
Nearly obsoleteNearly obsolete
Fiber-optic cableFiber-optic cable
Data is transmitted with light Data is transmitted with light pulsespulses
Glass strand instead of cableGlass strand instead of cable
Immune to interferenceImmune to interference
Very secureVery secure
Hard to work withHard to work with
Speeds up toSpeeds up to100 Gbps100 Gbps
Wireless MediaWireless Media
Data transmitted through the airData transmitted through the air
LANs use radio wavesLANs use radio waves
WANs use microwave signalsWANs use microwave signals
Easy to setupEasy to setup
Difficult to secureDifficult to secure
Internetwork
An Internetwork is the connection of two or more distinct computer networks or network segments via a common routing technology.
Any interconnection among or between public, private, commercial, industrial, or governmental networks may also be defined as an internetwork.
InternetworkInternetwork
Intranet An intranet is a set of networks, using the Internet Protocol and IP-based tools such
as web browsers and file transfer applications, that is under the control of a single administrative entity.
Most commonly, an intranet is the internal network of an organization Extranet
An extranet is a network or internetwork that is limited in scope to a single organization or entity but which also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities
by definition, an extranet cannot consist of a single LAN; it must have at least one connection with an external network.
Internet The Internet consists of a worldwide interconnection of governmental, academic,
public, and private networks based upon the networking technologies of the Internet Protocol Suite.
It is the successor of the Advanced Research Projects Agency Network (ARPANET) developed by DARPA of the U.S. Department of Defense.
The Internet is also the communications backbone underlying the World Wide Web (WWW).