Thinnet (10Base2) Characteristics (cont.): Size and scalability Allows a maximum of 185 m per network segment (see Figure 4-20) Noise immunity More resistant than twisted-pair wiring Less resistant Thicknet Figure 4-19: Thinnet BNC connectors

Thinnet (10Base2) Signal bounce Caused by improper termination on a bus network Travels endlessly between two ends of network Prevents new signals from getting through Figure 4-20: A 10Base2 Ethernet network

Twisted-Pair (TP) Cable Color-coded pairs of insulated copper wires twisted around each other and encased in plastic coating Twists in wire help reduce effects of crosstalk Number of twists per meter or foot known as twist ratio Alien Crosstalk When signals from adjacent cables interfere with another cable’s transmission Figure 21: Twisted-pair cable

Shielded Twisted-Pair (STP) STP cable consists of twisted wire pairs that are individually insulated and surrounded by shielding made of metallic substance Figure 4-22: STP cable

Unshielded Twisted-Pair Consists of one or more insulated wire pairs encased in a plastic sheath Does not contain additional shielding Figure 4-23: UTP cable

Unshielded Twisted-Pair To manage network cabling, it is necessary to be familiar with standards used on modern networks, particularly Category 3 (CAT3) and Category 5 (CAT5) Figure 4-24: A CAT5 UTP cable

Unshielded Twisted-Pair CAT1 – 2 wire pairs; suitable for voice only CAT2 – 4 wire pairs; up to 4 Mbps throughput CAT3 – 4 wire pairs; up to 10 Mbps and 16 Mhz signal CAT4 – 4 wire pairs; up to 10 Mbps CAT5 – 4 wire pairs; up to 100 Mbps and 100 Mhz signal CAT5e – up to 200 Mhz signal CAT6 – additional foil insulation; 6x throughput than CAT5 CAT7 – unfinished standard – up to 1Ghz

10BaseT Popular Ethernet networking standard that replaced 10Base2 and 10Base5 technologies “T” for twisted pair Figure 4-25: A 10BaseT Ethernet network

10BaseT Enterprise-wide network Spans entire organization Often services needs of many diverse users Figure 4-26: Interconnected 10BaseT segments

100BaseT Enables LANs to run at 100-Mbps data transfer rate Also known as Fast Ethernet Two 100BaseT specifications have competed for popularity as organizations move to 100-Mbps technology: 100BaseTX 100BaseT4 (can use CAT3 cabling)

100BaseVG Cousin of Ethernet 100 Mbps technologies VG stands for voice grade Also called 100VG-AnyLAN Originally developed by Hewlett-Packard and AT&T Now governed by IEEE standard 802.12 Requires more sophisticated NICs and can reduce network performance

Comparing STP and UTP Throughput Cost Connector Noise immunity Both can transmit up to 100 Mbps Cost Typically, STP is more expensive Connector Both use RJ-45 connectors and data jacks Noise immunity STP is more noise-resistant Size and scalability Maximum segment length for both is 100 meters

Fiber-Optic Cable Contains one or several glass fibers at its core Surrounding the fibers is a layer of glass called cladding Figure 4-28: A fiber-optic cable

Figure 4-29: Single-mode and multimode fiber-optic cables Single-mode fiber Carries light pulses along single path Multimode fiber Many pulses of light generated by LED travel at different angles Figure 4-29: Single-mode and multimode fiber-optic cables

Fiber-Optic Cable Throughput Cost Connector Reliable in transmitting up to 1 gigabit per second Cost Most expensive type of cable Connector You can use any of 10 different types of connectors

Fiber-Optic Cable Two popular connectors used with fiber-optic cable: ST connectors SC connectors Figure 4-30: ST and SC fiber connectors

Fiber-Optic Cable Noise immunity Size and scalability Unaffected by either EMI or RFI Size and scalability Network segments made from fiber can span 100 meters Signals transmitted over fiber can experience optical loss

10BaseF and 100BaseFX 10BaseF 100BaseFX Physical layer standard for networks specifying baseband transmission, multimode fiber cabling, and 10-Mbps throughput 100BaseFX Physical layer standard for networks specifying baseband transmission, multimode fiber cabling, and 100-Mbps throughput

Physical Layer Networking Standards Table 4-3: Physical layer networking standards

Cable Design and Management 1991 – TIA/EIA released its joint 568 Commercial Building Wiring Standard TIA – Telecommunication Industry Assoc. www.tiaonline.org EIA – Electronic Industries Assoc. www.eia.org T568A T568B

Cable Design and Management Cable plant Hardware comprising enterprise-wide cabling system Structured cabling Method for uniform, enterprise-wide, multivendor cabling systems Figure 4-31: TIA/EIA structured cabling subsystems

Cable Design and Management Entrance facilities Backbone wiring Backbone cabling that provides vertical connections between floors of a building are called risers Table 4-4: TIA/EIA specifications for backbone cabling

Cable Design and Management Equipment room Telecommunication closet Punch-down block is a panel of data receptors Patch panel is a wall-mounted panel of data receptors Figure 4-32: Patch panel (left) and punch-down block (right)

Cable Design and Management Horizontal wiring Max distance is 100m Figure 4-33: Horizontal wiring

Cable Design and Management Work area Patch cable is a relatively short section of twisted-pair cabling with connectors on both ends that connect network devices to data outlets Figure 4-34: Standard TIA/EIA wall jack

Cable Design and Management Figure 4-35: A structured cabling hierarchy

Figure 4-36: A typical UTP cabling installation Installing Cable Figure 4-36: A typical UTP cabling installation

Table 4-5: Pin numbers and color codes for an RJ-45 connector Installing Cable * T568A Standard Table 4-5: Pin numbers and color codes for an RJ-45 connector

Figure 4-37: RJ-45 terminations on a crossover Installing Cable Straight-through cable Terminations at both ends are identical Crossover cable Terminations locations of transmit and receiver wires on one end of cable are reversed Figure 4-37: RJ-45 terminations on a crossover

Installing Cable Do not untwist twisted-pair cables more than one-half inch before inserting them Do not strip off more than one inch of insulation from copper wire in twisted-pair cables Watch bend radius limitations for cable being installed Test each segment of cabling with cable tester Use only cable ties to cinch groups of cable together

Installing Cable Avoid laying cable across floor where it may sustain damage Install cable at least three feet away from fluorescent lights or other sources of EMI Always leave slack in cable runs If running cable in plenum, area above ceiling tile or below subflooring, make sure cable sheath is plenum-rated Pay attention to grounding requirements

Atmospheric Transmission Media Infrared transmission Infrared networks use infrared light signals to transmit data through space Direct infrared transmission depends on transmitter and receiver remaining within line of sight In indirect infrared transmission, signals can bounce off of walls, ceilings, and any other objects in their path

Atmospheric Transmission Media RF transmission Radio frequency (RF) transmission relies on signals broadcast over specific frequencies Very susceptible to interference Two most common RF technologies: Narrowband Concentrates RF energy at a single frequency Spread spectrum Distributed over several frequencies simultaneously

Choosing the Right Transmission Media Areas of high EMI or RFI Corners and small spaces Distance Security Existing infrastructure Growth