thinnet (10base2) characteristics (cont.): size and scalability size and scalability allows a...

Thinnet (10Base2)Thinnet (10Base2)

Characteristics Characteristics (cont.):(cont.): Size and scalabilitySize and scalability

Allows a maximum Allows a maximum of 185 m per of 185 m per network segment network segment (see Figure 4-20)(see Figure 4-20)

Noise immunityNoise immunityMore resistant than More resistant than twisted-pair wiringtwisted-pair wiring

Less resistant Less resistant ThicknetThicknet Figure 4-19: Thinnet BNC connectors

Thinnet (10Base2)Thinnet (10Base2)

Signal bounceSignal bounce Caused by Caused by

improper improper termination on termination on a bus networka bus network

Travels Travels endlessly endlessly between two between two ends of ends of networknetwork

Prevents new Prevents new signals from signals from getting throughgetting through

Figure 4-20: A 10Base2 Ethernet network

Twisted-Pair (TP) CableTwisted-Pair (TP) CableColor-coded pairs of Color-coded pairs of insulated copper wires insulated copper wires twisted around each twisted around each other and encased in other and encased in plastic coatingplastic coating

Twists in wire help Twists in wire help reduce effects ofreduce effects of crosstalkcrosstalk

Number of twists per Number of twists per meter or foot known as meter or foot known as twist ratiotwist ratio

Alien CrosstalkAlien Crosstalk When signals from When signals from

adjacent cables interfere adjacent cables interfere with another cable’s with another cable’s transmissiontransmission

Figure 21: Twisted-pair cable

Shielded Twisted-Pair (STP)Shielded Twisted-Pair (STP)

STP cable consists of twisted wire pairs that are STP cable consists of twisted wire pairs that are individually insulated and surrounded by shielding individually insulated and surrounded by shielding made of metallic substancemade of metallic substance

Figure 4-22: STP cable

Unshielded Twisted-PairUnshielded Twisted-Pair

Consists of one or more insulated wire pairs Consists of one or more insulated wire pairs encased in a plastic sheathencased in a plastic sheathDoes not contain additional shieldingDoes not contain additional shielding

Figure 4-23: UTP cable


To manage To manage network cabling, it network cabling, it is necessary to be is necessary to be familiar with familiar with standards used on standards used on modern networks, modern networks, particularly particularly Category 3 (CAT3) Category 3 (CAT3) and Category 5 and Category 5 (CAT5)(CAT5)

Figure 4-24: A CAT5 UTP cable


CAT1 – 2 wire pairs; suitable for voice onlyCAT1 – 2 wire pairs; suitable for voice onlyCAT2 – 4 wire pairs; up to 4 Mbps throughputCAT2 – 4 wire pairs; up to 4 Mbps throughputCAT3 – 4 wire pairs; up to 10 Mbps and 16 Mhz CAT3 – 4 wire pairs; up to 10 Mbps and 16 Mhz signalsignalCAT4 – 4 wire pairs; up to 10 MbpsCAT4 – 4 wire pairs; up to 10 MbpsCAT5 – 4 wire pairs; up to 100 Mbps and 100 Mhz CAT5 – 4 wire pairs; up to 100 Mbps and 100 Mhz signalsignalCAT5e – up to 200 Mhz signalCAT5e – up to 200 Mhz signalCAT6 – additional foil insulation; 6x throughput than CAT6 – additional foil insulation; 6x throughput than CAT5CAT5CAT7 – unfinished standard – up to 1GhzCAT7 – unfinished standard – up to 1Ghz

10BaseT10BaseTPopular Ethernet networking standard that replaced 10Base2 and 10Base5 Popular Ethernet networking standard that replaced 10Base2 and 10Base5 technologiestechnologies““T” for twisted pairT” for twisted pair

Figure 4-25: A 10BaseT Ethernet network

10BaseT10BaseT

Enterprise-wide Enterprise-wide networknetwork

Spans entire Spans entire organizationorganization

Often services Often services needs of many needs of many diverse usersdiverse users

Figure 4-26: Interconnected 10BaseT segments

100BaseT100BaseT

Enables LANs to run at 100-Mbps data Enables LANs to run at 100-Mbps data transfer ratetransfer rate

Also known as Also known as Fast EthernetFast Ethernet

Two 100BaseT specifications have competed Two 100BaseT specifications have competed for popularity as organizations move to 100-for popularity as organizations move to 100-Mbps technology:Mbps technology: 100BaseTX100BaseTX 100BaseT4 (can use CAT3 cabling)100BaseT4 (can use CAT3 cabling)

100BaseVG100BaseVG

Cousin of Ethernet 100 Mbps technologiesCousin of Ethernet 100 Mbps technologies

VG stands for voice gradeVG stands for voice grade

Also called 100VG-AnyLANAlso called 100VG-AnyLAN

Originally developed by Hewlett-Packard Originally developed by Hewlett-Packard and AT&Tand AT&T

Now governed by IEEE standard 802.12Now governed by IEEE standard 802.12

Requires more sophisticated NICs and Requires more sophisticated NICs and can reduce network performancecan reduce network performance

Comparing STP and UTPComparing STP and UTP

ThroughputThroughput Both can transmit up to 100 MbpsBoth can transmit up to 100 Mbps

CostCost Typically, STP is more expensiveTypically, STP is more expensive

ConnectorConnector Both use Both use RJ-45RJ-45 connectors and data jacks connectors and data jacks

Noise immunityNoise immunity STP is more noise-resistantSTP is more noise-resistant

Size and scalabilitySize and scalability Maximum segment length for both is 100 metersMaximum segment length for both is 100 meters

Fiber-Optic CableFiber-Optic Cable

Contains one or Contains one or several glass several glass fibers at its fibers at its corecore Surrounding Surrounding

the fibers is a the fibers is a layer of glass layer of glass called called claddingcladding

Figure 4-28: A fiber-optic cable


Single-mode Single-mode fiberfiber Carries light Carries light

pulses along pulses along single pathsingle path

Multimode fiberMultimode fiber Many pulses of Many pulses of

light generated light generated by LED travel at by LED travel at different anglesdifferent angles Figure 4-29: Single-mode and

multimode fiber-optic cables


ThroughputThroughput Reliable in transmitting up to 1 gigabit per Reliable in transmitting up to 1 gigabit per

secondsecond

CostCost Most expensive type of cableMost expensive type of cable

ConnectorConnector You can use any of 10 different types of You can use any of 10 different types of

connectorsconnectors


Two popular connectors used with fiber-optic cable:Two popular connectors used with fiber-optic cable: ST connectorsST connectors SC connectorsSC connectors

Figure 4-30: ST and SC fiber connectors


Noise immunityNoise immunity Unaffected by either EMI or RFIUnaffected by either EMI or RFI

Size and scalabilitySize and scalability Network segments made from fiber can span Network segments made from fiber can span

100 meters100 meters Signals transmitted over fiber can experience Signals transmitted over fiber can experience

optical lossoptical loss

10BaseF and 100BaseFX10BaseF and 100BaseFX

10BaseF10BaseF Physical layer standard for networks Physical layer standard for networks

specifying baseband transmission, specifying baseband transmission, multimode multimode fiber cablingfiber cabling, and 10-Mbps throughput, and 10-Mbps throughput

100BaseFX100BaseFX Physical layer standard for networks Physical layer standard for networks

specifying baseband transmission, specifying baseband transmission, multimode multimode fiber cablingfiber cabling, and 100-Mbps throughput, and 100-Mbps throughput

Physical Layer Networking Physical Layer Networking StandardsStandards

Table 4-3: Physical layer networking standards

Cable Design and ManagementCable Design and Management

1991 – TIA/EIA released its joint 568 1991 – TIA/EIA released its joint 568 Commercial Building Wiring StandardCommercial Building Wiring Standard TIA – Telecommunication Industry Assoc.TIA – Telecommunication Industry Assoc. www.tiaonline.orgwww.tiaonline.org EIA – Electronic Industries Assoc.EIA – Electronic Industries Assoc. www.eia.orgwww.eia.org

T568AT568A

T568BT568B


Cable plantCable plant Hardware Hardware

comprising comprising enterprise-wide enterprise-wide cabling systemcabling system

Structured cablingStructured cabling Method for Method for

uniform, uniform, enterprise-wide, enterprise-wide, multivendor multivendor cabling systemscabling systems

Figure 4-31: TIA/EIA structured cabling subsystems


Entrance facilitiesEntrance facilitiesBackbone wiringBackbone wiring Backbone cabling that provides vertical connections Backbone cabling that provides vertical connections

between floors of a building are called between floors of a building are called risersrisers

Table 4-4: TIA/EIA specifications for backbone cabling


Equipment roomEquipment room

Telecommunication Telecommunication closetcloset Punch-down Punch-down

blockblock is a panel of is a panel of data receptorsdata receptors

Patch panelPatch panel is a is a wall-mounted panel wall-mounted panel of data receptorsof data receptors

Figure 4-32: Patch panel (left) and punch-down block (right)


Horizontal wiringHorizontal wiringMax distance is 100mMax distance is 100m

Figure 4-33: Horizontal

wiring


Work areaWork area Patch cablePatch cable is a is a

relatively short relatively short section of twisted-section of twisted-pair cabling with pair cabling with connectors on both connectors on both ends that connect ends that connect network devices to network devices to data outletsdata outlets

Figure 4-34: Standard TIA/EIA wall jack


Figure 4-35: A structured cabling hierarchy

Installing CableInstalling Cable

Figure 4-36: A typical UTP

cabling installation


Table 4-5: Pin numbers and color codes for an RJ-45 connector

* T568A Standard


Straight-through cableStraight-through cable Terminations at both ends are identicalTerminations at both ends are identical

Crossover cableCrossover cable Terminations locations of transmit and receiver wires on one end Terminations locations of transmit and receiver wires on one end

of cable are reversedof cable are reversed

Figure 4-37: RJ-45

terminations on a

crossover


Do not untwist twisted-pair cables more than Do not untwist twisted-pair cables more than one-half inch before inserting themone-half inch before inserting them

Do not strip off more than one inch of insulation Do not strip off more than one inch of insulation from copper wire in twisted-pair cablesfrom copper wire in twisted-pair cables

Watch Watch bend radiusbend radius limitations for cable being limitations for cable being installedinstalled

Test each segment of cabling with cable testerTest each segment of cabling with cable tester

Use only cable ties to cinch groups of cable Use only cable ties to cinch groups of cable togethertogether


Avoid laying cable across floor where it Avoid laying cable across floor where it may sustain damagemay sustain damageInstall cable at least three feet away from Install cable at least three feet away from fluorescent lights or other sources of EMIfluorescent lights or other sources of EMIAlways leave slack in cable runsAlways leave slack in cable runs

If running cable in If running cable in plenumplenum, area above , area above ceiling tile or below subflooring, make sure ceiling tile or below subflooring, make sure cable sheath is plenum-ratedcable sheath is plenum-ratedPay attention to grounding requirementsPay attention to grounding requirements

Atmospheric Transmission MediaAtmospheric Transmission Media

Infrared transmissionInfrared transmission InfraredInfrared networks use infrared light networks use infrared light

signals to transmit data through spacesignals to transmit data through space Direct infrared transmissionDirect infrared transmission depends depends

on transmitter and receiver remaining on transmitter and receiver remaining within within line of sightline of sight

In In indirect infrared transmissionindirect infrared transmission, , signals can signals can bouncebounce off of walls, ceilings, off of walls, ceilings, and any other objects in their pathand any other objects in their path

Atmospheric Transmission MediaAtmospheric Transmission Media

RF transmissionRF transmission Radio frequency (RF)Radio frequency (RF) transmission relies transmission relies

on signals broadcast over specific frequencieson signals broadcast over specific frequencies Very susceptible to interferenceVery susceptible to interference Two most common RF technologies:Two most common RF technologies:

NarrowbandNarrowband Concentrates RF energy at a single frequencyConcentrates RF energy at a single frequency

Spread spectrumSpread spectrum Distributed over several frequencies simultaneouslyDistributed over several frequencies simultaneously

Choosing the Right Transmission Choosing the Right Transmission MediaMedia

Areas of high EMI or RFIAreas of high EMI or RFI

Corners and small spacesCorners and small spaces

DistanceDistance

SecuritySecurity

Existing infrastructureExisting infrastructure

GrowthGrowth

thinnet (10base2) characteristics (cont.): size and scalability size and scalability allows a...

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