Networking: Computer Networking: Computer ConnectionsConnections

CIS 105CIS 105

2005

ObjectivesObjectives Describe the basic components of a networkDescribe the basic components of a network Explain the methods of data transmission, Explain the methods of data transmission,

including types of signals, modulation, and including types of signals, modulation, and choices among transmission nodeschoices among transmission nodes

Differentiate among the various kinds of Differentiate among the various kinds of communications links and explain the need for communications links and explain the need for protocolsprotocols

Describe various network configurationsDescribe various network configurations List the components, types, and protocols of a List the components, types, and protocols of a

local area networklocal area network Describe the complexity of networkingDescribe the complexity of networking Describe some examples of networkingDescribe some examples of networking

Data Communications Data Communications SystemsSystems

Definition: Computer systems that Definition: Computer systems that transmit data over communications transmit data over communications lines such as telephone lines or lines such as telephone lines or cablescables

NetworkNetwork is a computer system that is a computer system that uses communications equipment to uses communications equipment to connect two or more computers and connect two or more computers and their resourcestheir resources

Networks: Why Use Networks: Why Use Them?Them?

Networking Benefits in a Networking Benefits in a NutshellNutshell

Reducing Hardware CostsReducing Hardware CostsEnabling Shared ApplicationsEnabling Shared ApplicationsBuilding Massive Information Building Massive Information ResourcesResources

Connecting PeopleConnecting People

Basic ComponentsBasic Components•Sending deviceSending device•Communications Communications linklink

•Receiving deviceReceiving device

Data Data Communications/Communications/TelecommunicatioTelecommunicatio

ns Modelns Model

Initiates instruction

Converts data

Signal path

Converts data

ReceivesInstruction

Digital and Analog Digital and Analog TransmissionTransmission

Digital transmissionDigital transmission Sends data as distinct pulses, either on or offSends data as distinct pulses, either on or off Similar to how data travels through computerSimilar to how data travels through computer

Analog transmissionAnalog transmission Continuous electrical signal in the form of a wave Continuous electrical signal in the form of a wave

(carrier wave)(carrier wave) Many communications media already in place for Many communications media already in place for

analog (voice) transmission – (Phone lines are analog (voice) transmission – (Phone lines are most common)most common)

Digital signal from computer must be converted Digital signal from computer must be converted to analog form to be transmitted over analog linesto analog form to be transmitted over analog lines

ModemModem Converts digital signal to analog and vice versaConverts digital signal to analog and vice versa

Data TransmissionData Transmission ModemsModems ISDN – integrated services digital network ISDN – integrated services digital network

(digital transmission)(digital transmission) DSL (digital subscriber line) DSL (digital subscriber line)

analog, but uses larger range of frequencies (faster)analog, but uses larger range of frequencies (faster) live connection – no dial-uplive connection – no dial-up Varieties: ADSL, RADSL, othersVarieties: ADSL, RADSL, others

Cable Modems (coaxial cable – same as TV Cable Modems (coaxial cable – same as TV cable) cable)

Cellular Modem (uses cellular system to Cellular Modem (uses cellular system to transfer data)transfer data)

Network Interface Card (NIC)Network Interface Card (NIC) aka LAN Adapteraka LAN Adapter Attachment point for specific type of cablesAttachment point for specific type of cables

Signal TypeSignal Type Analog Analog

(continuous)(continuous) Digital (individual Digital (individual

electrical pulses)electrical pulses) Broadband Broadband vs.vs.

BasebandBaseband

Transmission Transmission Characteristics Characteristics

Direction:Direction: Simplex Simplex

(security/fire alarms)(security/fire alarms)

Half-Duplex Half-Duplex (CB/fax/atm)(CB/fax/atm)

Full-Duplex Full-Duplex (intensive computing (intensive computing

required)required)Transmission Modes

AsynchronousSynchronous

Transfer Rates

BPS (Bits per second)

Bandwidth• Analog (Hz) hertz• Digital BPS

Click Here to View

Bandwidth Demo

Transmission Media: Transmission Media:

Twisted Pair CableTwisted Pair Cable Shielded (STP)Shielded (STP) Unshielded (UTP)Unshielded (UTP)

Coaxial CableCoaxial Cable Copper + 3 layers Copper + 3 layers

insulationinsulation Fiber Optic CableFiber Optic Cable

Glass/plastic – uses Glass/plastic – uses light to transmitlight to transmit

Faster; more signalsFaster; more signals Less interferenceLess interference SecuritySecurity Smaller sizeSmaller size

WAP (Wireless WAP (Wireless Application Protocol)Application Protocol)

Broadcast RadioBroadcast Radio BluetoothBluetooth

Radio frequencyRadio frequency Transceiver chipTransceiver chip

Cellular RadioCellular Radio Microwaves (line of site)Microwaves (line of site) Communications Communications

SatelliteSatellite InfraredInfrared

WirelessPhysical

Setting StandardsSetting Standards

ProtocolProtocol - a set of rules for the exchange of - a set of rules for the exchange of data between a terminal and a computer or data between a terminal and a computer or two computerstwo computers Agreement on how data is to be sent and receipt Agreement on how data is to be sent and receipt

acknowledgedacknowledged Needed to allow computers from different Needed to allow computers from different

vendors to communicatevendors to communicate Transmission Control Protocol/Internet Transmission Control Protocol/Internet

Protocol (TCP/IP)Protocol (TCP/IP) Permits any computer to communicate with the Permits any computer to communicate with the

InternetInternet Uses packet switchingUses packet switching

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

A collection of computers that share A collection of computers that share hardware, software, and datahardware, software, and data Typically personal computersTypically personal computers Typically within an office or buildingTypically within an office or building

LAN HardwareLAN Hardware Network cableNetwork cable Network interface card (NIC)Network interface card (NIC) RouterRouter GatewayGateway

Network Network TopologyTopology

The physical layout The physical layout of a networkof a network

Node - each Node - each computer, printer, computer, printer, or server on or server on networknetwork

Three common Three common topologiestopologies StarStar RingRing Bus Bus

Ring Network

Star Network

Bus Network

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

Can span the world or link Can span the world or link computers across towncomputers across town

ComponentsComponents Communications servicesCommunications services WAN hardwareWAN hardware WAN softwareWAN software

WAN CommunicationWAN Communication Provided by common carriersProvided by common carriers

Companies licensed by FCC to provide these Companies licensed by FCC to provide these servicesservices

SwitchedSwitched Also called a dial-up connectionAlso called a dial-up connection Most common is public telephone systemMost common is public telephone system

Dedicated Dedicated Provides permanent connection between two or Provides permanent connection between two or

more locationsmore locations Companies can build their own (microwave, fiber, etc.)Companies can build their own (microwave, fiber, etc.) Can also lease circuits from common carrier (leased lines)Can also lease circuits from common carrier (leased lines)

T1 and T3 high-capacity digital linesT1 and T3 high-capacity digital lines DSL or ISDN linesDSL or ISDN lines

Connecting NetworksConnecting NetworksHubHub aka concentrator or MAU (multistation access unit): central point for aka concentrator or MAU (multistation access unit): central point for

cables in a network.cables in a network.

RepeaterRepeater Accepts signal, amplifies it, retransmitsAccepts signal, amplifies it, retransmits

BridgeBridge Connects 2 LANS using same protocolConnects 2 LANS using same protocol

GatewayGateway Hardware/software combo connecting networks that use different Hardware/software combo connecting networks that use different protocolsprotocols

RouterRouter Connects multiple networks (including those w/different protocols). Can Connects multiple networks (including those w/different protocols). Can redirect traffic to another route if needed.redirect traffic to another route if needed.

IP switch IP switch used in place of router when networks use the Internet protocolused in place of router when networks use the Internet protocol

Base StationBase Station Wireless access point connects to a wired network and provides Wireless access point connects to a wired network and provides wireless transmit/receive over radius of several hundred feetwireless transmit/receive over radius of several hundred feet

MUXMUX Multiplexer combines data streams into a single data stream for Multiplexer combines data streams into a single data stream for transmission transmission

NetworkNetwork Collections of computers/devices connects that allows users to share Collections of computers/devices connects that allows users to share data, information, and hardware, softwaredata, information, and hardware, software

LANLAN Local Area Network. Connects computers in limited geo areaLocal Area Network. Connects computers in limited geo area

WANWAN Wide Area Network. Covers large geographical areaWide Area Network. Covers large geographical area

Client/Server NetworkClient/Server Network

Server computer controls networkServer computer controls network Often has several hard drives, fastest Often has several hard drives, fastest

printerprinter Client computer requests services Client computer requests services

from serverfrom server Thin client has little or no storageThin client has little or no storage

Processing approachesProcessing approaches Client/serverClient/server File serverFile server

Client/ServerClient/Server Client requests data from serverClient requests data from server Server passes only the requested dataServer passes only the requested data

File ServerFile Server Client requests data from serverClient requests data from server Server sends entire fileServer sends entire file

Client performs all data entry and Client performs all data entry and processing processing

File retransmitted to serverFile retransmitted to server

Peer-to-Peer NetworksPeer-to-Peer Networks

All computers have equal statusAll computers have equal status Users share each other’s files, Users share each other’s files,

printers, etc. as neededprinters, etc. as needed Common in small officesCommon in small offices Networks tend to be slowNetworks tend to be slow

Communications Communications ProtocolProtocol

Ethernet (IBM 1976)Ethernet (IBM 1976) Token Ring Token Ring (access through password)(access through password)

TCP/IPTCP/IP (Transmission control protocol/Internet protocol)(Transmission control protocol/Internet protocol) Break into packetsBreak into packets

Intranet/ExtranetIntranet/Extranet FirewallsFirewalls Home NetworkHome Network Client/Server NetworkClient/Server Network Bus NetworkBus Network

FirewallFirewall

Click Here to See Firewall Demo

Terms to Know: Terms to Know: NetworkingNetworking Asynchronous communicationAsynchronous communication BandwidthBandwidth Base stationBase station BridgeBridge BroadbandBroadband Cable modemsCable modems Client/server networkClient/server network Coaxial cableCoaxial cable Digital Subscriber Line (DSL)Digital Subscriber Line (DSL) EthernetEthernet Fiber-optic cableFiber-optic cable File serverFile server GatewayGateway HubHub Integrated Services Digital Network Integrated Services Digital Network

(ISDN)(ISDN) IP SwitchIP Switch

Local Area Network (LAN)Local Area Network (LAN) MUXMUX Network interface card (NIC)Network interface card (NIC) NodeNode Packet switching (packets)Packet switching (packets) ProtocolsProtocols RouterRouter Synchronous communicationSynchronous communication T1; T3T1; T3 TCP/IPTCP/IP Topologies (bus, ring, star)Topologies (bus, ring, star) Twisted Pair CableTwisted Pair Cable Wide Area Network (WAN)Wide Area Network (WAN) WirelessWireless

If Asked, Could You….If Asked, Could You…. Describe the basic components of a Describe the basic components of a

network?network? Explain the methods of data transmission, Explain the methods of data transmission,

including types of signals, modulation, including types of signals, modulation, and choices among transmission nodes?and choices among transmission nodes?

Differentiate among the various kinds of Differentiate among the various kinds of communications links and explain the communications links and explain the need for protocols?need for protocols?

Describe various network configurations?Describe various network configurations? List the components, types, and protocols List the components, types, and protocols

of a local area network?of a local area network? Describe the complexity of networking?Describe the complexity of networking? Describe some examples of networking?Describe some examples of networking?

SourcesSources

Capron; Computers: Tools for An Capron; Computers: Tools for An Information Age, 8Information Age, 8thth Ed. 2003 Ed. 2003

Pfaffenberger; Computers in Your Pfaffenberger; Computers in Your Future 2003Future 2003

Microsoft ClipartMicrosoft Clipart HowStuffWorksHowStuffWorks-Firewalls-Firewalls