synapseindia reviews
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Synapse india Reviews
Computer Network -
Basic ConceptsComputer NetworksCommunication ModelTransmission
ModesCommunication TypesClassification Of Computer Networks By
ScaleBy StructureBy TopologyNetwork MediaInternetworking
Computer NetworkA computer network is a group of interconnected computers.
It allows computers to communicate with each other and to share resources and information.
First Network : The Advanced Research Projects Agency (ARPA) funded the design of the "Advanced Research Projects Agency Network" (ARPANET) for the United States Department of Defense
Communication Model
Communication ModelSourcegenerates data to be transmittedTransmitterConverts data into transmittable signalsTransmission SystemCarries dataReceiverConverts received signal into dataDestinationTakes incoming data
Communication Model
Communication TypesUnicasting (one-to-one)
Multicasting (one-to-many)
Broadcasting (one-to-all)
Network ClassificationBy Size or ScaleLANWANMANCANPAN
Local Area Network (LAN)Contains printers, servers and computersSystems are close to each otherContained in one office or buildingOrganizations often have several LANS
Teaching tipUse a real world example to describe an organization with interconnected LANs.
Wide Area Networks (WAN)Two or more LANs connectedOver a large geographic areaTypically use public or leased linesPhone linesSatelliteThe Internet is a WAN
Teaching tipUse a real world example to describe an organization with interconnected LANs.
Metropolitan Area Network (MAN)Large network that connects different organizationsShares regional resourcesA network provider sells time
Campus Area Networks (CAN)A LAN in one large geographic areaResources related to the same organizationEach department shares the LAN
Personal Area Network (PAN)Very small scale networkRange is less than 2 metersCell phones, PDAs, MP3 players
Network ClassificationBy Structure / Functional RelationshipClient / ServerPeer to Peer (P2PN)
Client/Server networkNodes and servers share data rolesNodes are called clientsServers are used to control accessDatabase softwareAccess to data controlled by serverServer is the most important computer
Peer to peer networks (P2PN)All nodes are equalNodes access resources on other nodesEach node controls its own resourcesMost modern OS allow P2PNDistributed computing is a formKazaa
Network ClassificationBy Topology / Physical ConnectivityBUSSTARRINGMESHTREE
Network TopologyLogical layout of wires and equipmentChoice affects Network performanceNetwork sizeNetwork collision detection
BUSAlso called linear bus
One wire connects all nodes
Terminator ends the wires
AdvantagesEasy to setupSmall amount of wire
DisadvantagesSlowEasy to crash
STARAll nodes connect to a hubPackets sent to hubHub sends packet to destination
AdvantagesEasy to setupOne cable can not crash network
DisadvantagesOne hub crashing downs entire networkUses lots of cable
Most common topology
RINGNodes connected in a circle
Tokens used to transmit dataNodes must wait for token to send
AdvantagesTime to send data is knownNo data collisions
DisadvantagesSlowLots of cable
MESHAll computers connected together
Internet is a mesh network
AdvantageData will always be delivered
DisadvantagesLots of cableHard to setup
TREEHierarchal Model
AdvantagesScaleableEasy ImplementationEasy Troubleshooting
Network MediaLinks that connect nodesChoice impactsSpeedSecuritySize
Twisted-pair cablingMost common LAN cable
Called Cat5 or 100BaseT
Four pairs of copper cable twisted
May be shielded from interference
Speeds range from
1 Mbps to 1,000 Mbps
Coaxial cableSimilar to cable TV wire
One wire runs through cable
Shielded from interference
Speeds up to 10 Mbps
Nearly obsolete
Fiber-optic cableData is transmitted with light pulses
Glass strand instead of cable
Immune to interference
Very secure
Hard to work with
Speeds up to
100 Gbps
Wireless MediaData transmitted through the air
LANs use radio waves
WANs use microwave signals
Easy to setup
Difficult to secure
Teaching tipUse a real world example to describe an organization with interconnected LANs. Teaching tipUse a real world example to describe an organization with interconnected LANs.