CS335 Networking & Network Administration Thursday April 1

Transmission Media Computer communication involves encoding data in a form of energy Electric current Radio waves Light beams

Transmission Media Copper used because of low resistance to electric current means signals travel further Interference – electrical energy from one wire to another UTP – Unshielded twisted pair – used by phone systems as well STP – Shielded twisted pair Coaxial Cable (thicknet and thinnet) Fiber optic cable

Unshielded Twisted Pair UTP 4 pairs of color coded 22 or 24 gauge copper External diameter of.43 cm is advantage for installation Disadvantage is that it is more prone to electrical noise and interference. The twists cancel out electrical interference and prevent signals from interfering (crosstalk)

UTP IEEE (Institute of Electrical and Electronics Engineers) standards on number of twists per meter 100 meter maximum length for 10BaseT CAT 3,4,5,5e,6 cables types 10BaseT – 10 megabit 100BaseT – 100 megabit (fast ethernet) 1000BaseT – 1000 megabit (gigabit) RJ45 connectors

UTP TIA (Telecommunications Industry Association) EIA (Electronic Industries Alliance) TIA/EIA networking standards 568-A standards for cable performance CAT 3,4,5 90 meter cable runs 10 meter patch cord and cross connect jumpers

UTP Implementation 4 pair 4 tip conductors T1 through T4 4 ring conductors R1 through R4 First pair is T1 and R1, etc. RJ 45 PinT is Tip, R is Ring 1Pair 2 T2 2Pair 2 R2 3Pair 3 T3 4Pair 1 R1 5Pair 1 T1 6Pair 3 R3 7Pair 4 T4 8Pair 4 R4

UTP Orange – White orange Blue – White blue Green – White green Brown – White brown Straight through and crossover cables Cable testers

UTP Wiring

STP Shielded Twisted Pair Shielded Reduces crosstalk Reduces EMI (Electromagnetic interference) RFI (Radio frequency interference)

Coaxial Cable Run longer distances More durable Thicknet hardly used anymore Thinnet (OD=.35cm) more flexible Not used much more Found in legacy installations

Fiber-Optic cable Shielded glass fiber LED’s or lasers transmit light Receiver on other end Polished ends No electrical interference Carry signals much further Light can carry more data the electrical One fiber can carry data instead of 2 wires to complete electrical circuits

Fiber Single Mode – axial, light travels down the axis of the cable Used in WAN’s – faster (up to 10 Gbps) Multimode – light enters the glass pipe at different angles and travels nonaxially bouncing off the walls of the glass tube Used more in LAN’s

Fiber Can’t bend 90 degrees but can form a circle Hard to repair Need highly polished ends on installation

Radio (Wireless) Data encoded on electromagnetic radio waves Standard IEEE

Satellite Geosynchronous Low earth orbit Microwave – line of sight Infrared – short distance, line of sight

Ethernet Specifications Summary 10 Base210 Base510 BaseT100 BaseTX100 BaseFX Media Thin coaxThick coaxTIA/EIA UTP Cat 3,4,5, and 5e TIA/EIA UTP Cat 5, and 5e 62.2/125 micron multimode fiber Connector Type BNCAUI/DIX (to a transceiver) RJ-45 Duplex media interface connector (MIC) st Maximum Segment length 185 m500 m100 m 412 m Topology Bus Star Point-to-point Transfer Rate 10 Mbps 100 Mbps

LAN Technologies Ethernet Token Ring FDDI (Fiber Distributed Data Interface)