NETWORKING MEDIA b Shielded twisted-pair - 2 pair, 150 ohm b unshielded-twisted pair - 4 pair, 100 ohm b fiber optic cable - 2 fibers b coaxial cable - (not recommended)

Twisted Pair Cabling b Shielded Twisted Pair Provides resistance to EMI and radio frequencyProvides resistance to EMI and radio frequency Cancellation and twisting of wires, shieldingCancellation and twisting of wires, shielding More expensiveMore expensive Cable length 100mCable length 100m b Unshielded twisted- pair relies on cancellation effect number of twists varies Less expensive Cable length 100m Fastest copper based media today

COAXIAL CABLE b Copper conductor in center b Flexible insulation b Metallic foil or copper braid acts as second wire in circuit b Max. length 500m b Thicker than Twisted pair, more difficult to work with

FIBER OPTIC CABLE b Not susceptible to EMI b Higher data rates than any other media b Each optical fiber is surrounded by layers of plastic such as Kevlar, and an outer jacket b Max. cable length up to 2km b Most expensive

TIA/EIA STANDARDS u Horizontal cabling b telecommunications closets b backbone cabling b equipment rooms b work areas b entrance facilities

Cabling b Crossover Cable - used to connect one device to another b Straight through - used to connect to hub or patch panel b Rollover or console cable - used to connect a PC to the router for purposes of accessing the router

10BASE-T b Cat 5 twisted pair b Terminated with RJ-45 b Layer 1 device b Carries bits

Patch Panel b Groups of Rj-45 (12, 24, 48) PORTS b Rack mounted b Front sides RJ-45 jacks b Back sides punch-down Blocks b Layer 1 device

Repeater b Regenerates and retime signals b Enables cables to extend farther to reach longer distances b Deal with packets at bit level (1) b Increase number of nodes that can be connected to a network b Cannot filter traffic

Multiport Repeaters (Hubs) b Regenerate, amplify and retime signals b Deal only with bits b Layer 1 device

COLLISIONS b If more than one node attempts to transmit at the same time b Packets destroyed, bit by bit b Two devices trying to occupy the same medium (wire) at the same time

COLLISION DOMAIN b Repeaters and hubs extend the collision domain b Ethernet rule of thumb rule. Five sections of network, four repeaters or hubs, three sections of the network are mixing segments, two sections are link segments, and one large collision domain

SEGMENTATION b Reduces size of collision domain b Networking device used are bridges, switches and routers b Eliminate unnecessary traffic on busy network by dividing into segments and filtering traffic based on station address

Bus Topology b All nodes connected directly to one line b Wired to a common wire b Disadvantage - break in cable disconnects host from each other

RING TOPOLOGY b Single closed ring consisting of nodes and links b Connected to only two adjacent nodes b Each station must pass info to adjacent station

DUAL RING b Two concentric rings, each linked only to its adjacent ring neighbor, not connected b Each network device is part of two independent ring topologies b Acts like two independent rings, only one at a time is used.

STAR TOPOLOGY b Has a central node with all links radiating from it b Allows all other nodes to communicate with each other b If central node fails, whole network is disconnected. b Info goes through one device

EXTENDED START TOPOLOGY b Repeats a star topology, except each node that links to the central node is the center of another star b Has a core star topology b Each end node of core topology acts as the center of its own star topology b Keeps wiring run shorter b Hierarchical, info encouraged to stay local

COMPLETE (MESH) TOPOLOGY b Every node is physically connected to each other node b Information can flow if one link goes down b Disadvantage is for anything more than a small number of nodes the amount of media is overwhelming