Networking Essentials – Eric Vanderburg © 2005

Network Topology & DesignNetwork Topology & DesignChapter 4Chapter 4

Networking Essentials – Eric Vanderburg © 2005

Bus topologyBus topology Bus topology advantagesBus topology advantages

InexpensiveInexpensive Easy to designEasy to design Easy to implementEasy to implement

Bus topology disadvantagesBus topology disadvantages Difficult to troubleshootDifficult to troubleshoot Requires terminationRequires termination

Networking Essentials – Eric Vanderburg © 2005

Star topologyStar topology Star topology advantagesStar topology advantages

Break in one cable does notBreak in one cable does not affect other devices (except up links) affect other devices (except up links)

Easy to locate problemsEasy to locate problems Easy to installEasy to install Does not require termination like bus Does not require termination like bus

topologytopology Star topology disadvantagesStar topology disadvantages

Center of star topology device (hub) Center of star topology device (hub) can be expensivecan be expensive

Hub failure can affect entire topologyHub failure can affect entire topology Amount of cable is expensiveAmount of cable is expensive

Networking Essentials – Eric Vanderburg © 2005

Ring topologyRing topology Ring topology advantagesRing topology advantages

Prevents network collisionsPrevents network collisions Each station acts like a repeaterEach station acts like a repeater

Ring topology disadvantagesRing topology disadvantages Cable break can affect all devicesCable break can affect all devices Temporarily shut down network to add Temporarily shut down network to add

a new stationa new station Maintenance and monitoring is difficultMaintenance and monitoring is difficult

Networking Essentials – Eric Vanderburg © 2005

Network ArchitectureNetwork Architecture IEEE 802IEEE 802

CSMA/CD (802.3)CSMA/CD (802.3) Token Ring (802.5)Token Ring (802.5)

NADN (Nearest Active Downstream NADN (Nearest Active Downstream Neighbor)Neighbor)

NAUN (Nearest Active Upstream Neighbor)NAUN (Nearest Active Upstream Neighbor) Node with the token can send dataNode with the token can send data Predictable send/receive timePredictable send/receive time

Wireless Technologies (802.11)Wireless Technologies (802.11) FDDI (Fiber Distributed Data Interface)FDDI (Fiber Distributed Data Interface)

Networking Essentials – Eric Vanderburg © 2005

MediaMedia Twisted-Pair cabling have the Twisted-Pair cabling have the

following in commonfollowing in common Copper based data transmissionCopper based data transmission Copper wires come in pairsCopper wires come in pairs Each Wire of a pair is twisted around Each Wire of a pair is twisted around

each other to protect against NEXT each other to protect against NEXT (Near End Crosstalk)(Near End Crosstalk)

Copper wires are enclosed in a sheathCopper wires are enclosed in a sheath All wire pairs are enclosed in a sheathAll wire pairs are enclosed in a sheath

Networking Essentials – Eric Vanderburg © 2005

Media (continued)Media (continued) UTP (Unshielded twisted-pair)UTP (Unshielded twisted-pair)

Advantages of UTP cableAdvantages of UTP cable Thin and flexible Thin and flexible Easy to installEasy to install Many modern buildings come with CAT 5 installedMany modern buildings come with CAT 5 installed Small size does not fill up wiring ducts fastSmall size does not fill up wiring ducts fast Inexpensive per footInexpensive per foot

Disadvantages of UTP cableDisadvantages of UTP cable Susceptible to interferenceSusceptible to interference Cable length is 100 meters or 328 feetCable length is 100 meters or 328 feet

RJ (Register Jacks)RJ (Register Jacks) RJ-45RJ-45

Networking Essentials – Eric Vanderburg © 2005

Media (continued)Media (continued)

Networking Essentials – Eric Vanderburg © 2005

Media (continued)Media (continued) STP (Shielded twisted-pair)STP (Shielded twisted-pair)

Advantages of STP cableAdvantages of STP cable Greater protection from interferenceGreater protection from interference Thin and flexible Thin and flexible Overall it is easy to installOverall it is easy to install

Disadvantages of STP cableDisadvantages of STP cable Inexpensive per foot but more than UTPInexpensive per foot but more than UTP STP must be grounded, problems exists if not STP must be grounded, problems exists if not

grounded properlygrounded properly More difficult to install than UTPMore difficult to install than UTP Small size but does fill up wiring ducts faster than Small size but does fill up wiring ducts faster than

UTPUTP

Networking Essentials – Eric Vanderburg © 2005

Media (continued)Media (continued) Coaxial cabling (Thicknet and Thinnet)Coaxial cabling (Thicknet and Thinnet)

Advantages of coaxial cablingAdvantages of coaxial cabling Cable lengths are longer than UTP/STPCable lengths are longer than UTP/STP Less susceptible to interference than UTPLess susceptible to interference than UTP Hubs are not required, direct connectionHubs are not required, direct connection

Disadvantages of coaxial cablingDisadvantages of coaxial cabling Thicknet is very difficult to installThicknet is very difficult to install More expensive than UTPMore expensive than UTP Difficult to troubleshootDifficult to troubleshoot

Networking Essentials – Eric Vanderburg © 2005

Media (continued)Media (continued) Thinnet and Thicknet ConnectorsThinnet and Thicknet Connectors

RG-58 cablingRG-58 cabling BNCBNC AUI (Attachment unit interface)AUI (Attachment unit interface) Barrel connectorsBarrel connectors T-connectorsT-connectors TerminatorsTerminators

Networking Essentials – Eric Vanderburg © 2005

Media (continued)Media (continued) Fiber-Optic cableFiber-Optic cable

Advantages of fiber-Advantages of fiber-optic cablingoptic cabling

Transmit data over Transmit data over long distanceslong distances

Not susceptible to EMINot susceptible to EMI High transmission ratesHigh transmission rates Not susceptible to Not susceptible to

eavesdroppingeavesdropping Small cable sizeSmall cable size

Disadvantages of fiber-optic cablingDisadvantages of fiber-optic cabling ExpensiveExpensive Cable can be easily damaged during install making Cable can be easily damaged during install making

installations more difficultinstallations more difficult Manual termination of ends is time consumingManual termination of ends is time consuming

Networking Essentials – Eric Vanderburg © 2005

Fiber Optic ConnectorsFiber Optic Connectors

ST (Straight Tip) SC (Straight Connection)

MT-RJtwo cables in one

RJ-45 clone

SMA (Subminiature Type A)MIC (Medium Interface Connector)LC (Link Control)

Networking Essentials – Eric Vanderburg © 2005

Signal Degradation Signal Degradation (continued)(continued)

Reduce EMI/RFIReduce EMI/RFI Do not place copper media next toDo not place copper media next to

Fluorescent lightsFluorescent lights Generators/motorsGenerators/motors High-voltage electrical wireHigh-voltage electrical wire

Proper installationProper installation Use quality cableUse quality cable Use shielded cablingUse shielded cabling Use repeaters to strengthen signal on Use repeaters to strengthen signal on

long cable runslong cable runs

Networking Essentials – Eric Vanderburg © 2005

CablingCabling Horizontal Cabling – cables going Horizontal Cabling – cables going

from the wiring closet to end nodesfrom the wiring closet to end nodes Vertical Cabling – Backbone of the Vertical Cabling – Backbone of the

networknetwork

Networking Essentials – Eric Vanderburg © 2005

Wiring ClosetsWiring Closets MDF (Main MDF (Main

distribution facility) – distribution facility) – Central wiring closet Central wiring closet when more than one when more than one is usedis used

IDF (Intermediate IDF (Intermediate distribution facility) – distribution facility) – wiring closets off the wiring closets off the MDFMDF

Networking Essentials – Eric Vanderburg © 2005

LAN Design ModelsLAN Design Models Two basic design strategiesTwo basic design strategies

MeshMesh all routers are peers, interconnected, and all routers are peers, interconnected, and

exchanging informationexchanging information Easy to set upEasy to set up

Hierarchical Hierarchical Easy to troubleshootEasy to troubleshoot Easier to manageEasier to manage Can scale betterCan scale better Can obtain better performance dataCan obtain better performance data

Networking Essentials – Eric Vanderburg © 2005

LAN Design ModelsLAN Design Models Three-layer network modelThree-layer network model

Core – WAN connectivity between sites Core – WAN connectivity between sites (usually owned by the ISP)(usually owned by the ISP)

Distribution – Connects buildings on Distribution – Connects buildings on the LAN or wiring closets in a buildingthe LAN or wiring closets in a building

Access layer – Connects nodes into the Access layer – Connects nodes into the networknetwork

Networking Essentials – Eric Vanderburg © 2005

AcronymsAcronyms AC, Alternating CurrentAC, Alternating Current AUI, Attachment Unit InterfaceAUI, Attachment Unit Interface CMIP, Common Management Information CMIP, Common Management Information

ProtocolProtocol EIA, Electronic Industries AllianceEIA, Electronic Industries Alliance TIA, Telecommunications Industry TIA, Telecommunications Industry

AssociationAssociation FDDI, Fiber Distributed Data InterfaceFDDI, Fiber Distributed Data Interface IDF, Intermediate Distribution FacilityIDF, Intermediate Distribution Facility MDF, Main Distribution FacilityMDF, Main Distribution Facility MID, Management Information baseMID, Management Information base

Networking Essentials – Eric Vanderburg © 2005

AcronymsAcronyms MAU, Multistation Access UnitMAU, Multistation Access Unit NEXT, Near End CrosstalkNEXT, Near End Crosstalk NADN, Nearest Active Downstream NADN, Nearest Active Downstream

NeighborNeighbor NAUN, Nearest Active Upstream NeighborNAUN, Nearest Active Upstream Neighbor POP, Point of PresencePOP, Point of Presence SAP, Service Access PointSAP, Service Access Point STP, Shielded Twisted PairSTP, Shielded Twisted Pair TDR, Time Domain ReflectometerTDR, Time Domain Reflectometer UTP, Unshielded Twisted PairUTP, Unshielded Twisted Pair