Chapter 1

Chapter 1

Guide to Networking Essentials 7th Edition Chapter 4 Network Media Objectives Define the primary cables used in wired networking Describe the characteristics of the major types of fiber-optic media Explain the technologies used for wireless networking Guide to Networking Essentials, 7th Edition Cengage Learning 2016

2 Wired Networking Wired networking uses tangible physical media called cables Two broad categories of cables: copper wire and fiber optic The main differences between the two types: Composition of signals (electricity or light) Speed at which signals can be sent Distance the signals can effectively travel Guide to Networking Essentials, 7th Edition Cengage Learning 2016 3

Criteria for Choosing Network Media Bandwidth Rating number of bits per second that can be transmitted across a medium A factor determining bandwidth is how bit signals are represented on the medium (called encoding) When possible, choose a cabling category thats compatible with the standard you want to implement now but will support growth and faster speeds Maximum Segment Length maximum length of cable between two network devices Each cable type can transport data only so far before its signals begin to weaken beyond what can be read by a receiving device (called attenuation) Guide to Networking Essentials, 7th Edition

Cengage Learning 2016 4 Criteria for Choosing Network Media Maximum Segment Length maximum length of cable between two network devices (called cable segment) Any intermediate passive devices, such as wall jacks, are part of the total segment length Each cable type can transport data only so far before its signals begin to weaken beyond what can be read by a receiving device (called attenuation) Guide to Networking Essentials, 7th Edition Cengage Learning 2016

5 Criteria for Choosing Network Media Interference and Eavesdropping Susceptibility Interference to electrical signals on copper media comes in the form of electromagnetic interference (EMI) and radio frequency interference (RFI) Motors, transformers, fluorescent lights and other sources of intense electrical activity can emit both EMI and RFI. RFI can also affect wireless networks if the frequencies are in the same range Crosstalk - interference one wire generates on another wire when both wires are in a bundle Copper wire is susceptible to electronic eavesdropping Fiber-optic media carries light signals and is not

susceptible to interference or eavesdropping Guide to Networking Essentials, 7th Edition Cengage Learning 2016 6 Criteria for Choosing Network Media Cable Grade Building and fire codes include specific cabling requirements Cables ran between a false ceiling and the true ceiling (plenum) must be plenum-rated UTP Cabling is marked as communication cable riser (CMR) or communication cable plenum (CMP) CMR can only be used for building risers or in cable trays

CMP is suitable for use in plenum spaces Guide to Networking Essentials, 7th Edition Cengage Learning 2016 7 Criteria for Choosing Network Media Connection Hardware Every type of cable has connectors that influence the kinds of hardware the cable can connect to You must make sure the media you select can be supported by the network device Guide to Networking Essentials, 7th Edition Cengage Learning 2016

8 Other Media Considerations Ease of installation factors to consider: Medias minimum bend radius, which limits the angle at which a cable can be bent to run around corners Cost and time needed to terminate the medium Physical environment types of walls and ceilings, EMI or RFI Testability A network that works might be crippled by excessive errors It is important to certify whether the cable meets requirements for its category Total cost includes cabling, connectors, termination panels, wall jacks, termination tools, testing equipment

and time Guide to Networking Essentials, 7th Edition Cengage Learning 2016 9 Coaxial Cable Often called coax for short Once was the predominant form of network cabling Inexpensive and easy to install Started to phase out in the early 1990s Still used primarily in connecting a cable modem to the wall outlet your cable TV/Internet provider installs

Guide to Networking Essentials, 7th Edition Cengage Learning 2016 10 Twisted-Pair Cable Comes in two types: unshielded and shielded Consists of one or more pairs of insulated strands of copper wires twisted around one another and housed in an outer jacket Twists are necessary to improve resistance to crosstalk from wires and EMI from outside sources The more twists per unit length, the better resistance to EMI and crosstalk More expensive TP is twisted more than less

expensive and provides a better pathway for higher bandwidth networks Guide to Networking Essentials, 7th Edition Cengage Learning 2016 11 Twisted-Pair Cable Guide to Networking Essentials, 7th Edition Cengage Learning 2016 12 Unshielded Twisted-Pair Cable

Most networks use Unshielded Twisted-Pair (UTP) Consists of four pairs of insulated wires Rated according to categories devised by the Telecommunications Industry Association (TIA) and Electronic Industries Alliance (EIA) and American National Standards Institutes (ANSI) Categories 1 6a are accepted in US Two additional categories arent yet TIA/EIA standards and might never be in US Europe has accepted Category 7 and 7a, which specify that each wire pair is shielded Guide to Networking Essentials, 7th Edition Cengage Learning 2016 13

Unshielded Twisted-Pair Cable Categories 5e and 6 UTP Cabling Characteristics These categories are the most popular types of UTP cabling in todays networks Guide to Networking Essentials, 7th Edition Cengage Learning 2016 14 Shielded Twisted-Pair Cable Includes shielding to reduce crosstalk and interference Has a wire braid inside the sheath material or a foil wrap Best to use in electrically noisy environments or very

high-bandwidth applications Guide to Networking Essentials, 7th Edition Cengage Learning 2016 15 Twisted-Pair Cable Plant Components RJ-45 Connectors STP and UTP uses registered jack 45 (RJ-45) Most commonly used in patch cables, which are used to connect computers to hubs, switches, and RJ-45 wall jacks Guide to Networking Essentials, 7th Edition

Cengage Learning 2016 16 Twisted-Pair Cable Plant Components Patch cable short cable for connecting a computer to an RJ-45 wall jack or connecting a patch-panel port to a switch or hub Can be made with inexpensive tools, two RJ-45 plugs and a length of TP cable Guide to Networking Essentials, 7th Edition Cengage Learning 2016 17

Twisted-Pair Cable Plant Components Patch Panels used to terminate long runs of cable from where the computers are to the wiring closet (where the switches and hubs are) Distribution racks hold network equipment such as routers and switches, plus patch panels and rack-mounted servers Also called 19 racks because the upright rails are 19 apart Guide to Networking Essentials, 7th Edition Cengage Learning 2016 18

Structured Cabling: Managing and Installing a UTP Cable Plant Structured cabling specifies how cabling should be organized, regardless of the media type or network architecture Large networks typically use most or all of these: Work area Horizontal wiring Telecommunication closets Equipment rooms

Backbone or vertical wiring Entrance facilities Guide to Networking Essentials, 7th Edition Cengage Learning 2016 19 Structured Cabling: Managing and Installing a UTP Cable Plant Work Area where workstations and other user devices are located Faceplates and wall jacks are installed in the work area Patch cable connect computers and printers to wall jacks Guide to Networking Essentials, 7th Edition

Cengage Learning 2016 20 Structured Cabling: Managing and Installing a UTP Cable Plant Horizontal wiring runs from the work areas wall jack to the telecommunication closet Wiring from the wall jack to the patch panel should be no longer than 90 meters (plus 10 meters for patch cables) Telecommunications Closet TC provides connectivity to computer equipment in the nearby work area Typical equipment includes patch panels to terminate horizontal wiring runs, hubs and switches

A TC that houses the cabling and devices for work area computers is referred to as an intermediate distribution frame (IDF) Guide to Networking Essentials, 7th Edition Cengage Learning 2016 21 Structured Cabling: Managing and Installing a UTP Cable Plant Guide to Networking Essentials, 7th Edition Cengage Learning 2016 22

Structured Cabling: Managing and Installing a UTP Cable Plant Equipment Room houses servers, routers, switches, and other major network equipment and serves as a connection point for backbone cabling An equipment room thats the connection point between IDFs is called a main distribution frame (MDF) An MDF can be the main cross-connect for the entire network or it might serve as the connecting point for backbone cabling between buildings Each building often has its own MDF Guide to Networking Essentials, 7th Edition Cengage Learning 2016

23 Structured Cabling: Managing and Installing a UTP Cable Plant Backbone Cabling interconnects IDFs and MDFs Runs between floors or wings of a building and between buildings Frequently fiber-optic cable but can also be UTP if the distance between TCs is less than 90 meters

Guide to Networking Essentials, 7th Edition Cengage Learning 2016 24 Structured Cabling: Managing and Installing a UTP Cable Plant Entrance Facility the location of the cabling and equipment that connects a corporate network to a third-party telecommunications provider Can also serve as an equipment room and the main cross-connect for all backbone cabling Where a connection to a WAN is made Demarcation point: point where corporate LAN equipment ends and a third-party providers equipment and cabling begins

Guide to Networking Essentials, 7th Edition Cengage Learning 2016 25 Installing UTP Cabling Cable termination putting RJ-45 plugs on the ends of cable or punching down wires into terminal blocks on a jack or patch panel Some tools needed: Wire cutters Crimping Tool Cable Tester Punchdown Tool

Cable Stripper RJ-45 plugs/jacks Guide to Networking Essentials, 7th Edition Cengage Learning 2016 26 Installing UTP Cabling When making a cable or terminating a cable at a jack or patch panel It is important to get the colored wires arranged in the correct order

There are two standards: 568A and 568B Guide to Networking Essentials, 7th Edition Cengage Learning 2016 27 Straight-Through Versus Crossover Cable Standard patch cables are called straight-through cables (same wiring standard on both ends) Crossover cables use 568A standard on one side of the cable and 568B standard on the other side Crosses the transmit and receive wires so that transmit on one end connects to receive on the other

This type of cable is often needed when you connect two devices of the same type to one another For a 1000BaseT crossover cable, you have to cross the blue and brown pins because theyre used in 1000BaseT Guide to Networking Essentials, 7th Edition Cengage Learning 2016 28 Straight-Through Versus Crossover Cable Guide to Networking Essentials, 7th Edition Cengage Learning 2016

29 Medium Dependent Interface Network devices that connect by using RJ-45 plugs over twisted-pair cabling are classified as medium dependent interface (MDI) devices or MDI crossed (MDI-X) devices MDI devices transmit on pins 1 and 2 and receive on pins 3 and 6 PC NICs and routers are examples MDI-X devices receive on pins 1 and 2 and transmit on pins 3 and 6 Hubs and switches are examples When two switches (or any other like devices) need to be connected, you use a crossover cable so that transmit and

receive wires get crossed Guide to Networking Essentials, 7th Edition Cengage Learning 2016 30 Why Two Transmit and Two Receive Wires? One wire pair is used for transmit (labeled transmit+/transmit-) and one pair for receive (labeled receive+/receive-) The plus and minus symbols indicate that the wires carry a positive and negative signal This differential signal mitigates the effect of crosstalk and noise on the cable

Guide to Networking Essentials, 7th Edition Cengage Learning 2016 31 Fiber-Optic Cable Bits are transmitted as pulses of light instead of electricity Immune to electrical interference Highly secure electronic eavesdropping is eliminated Composition A slender cylinder of glass fiber called the core is surrounded by a concentric layer of glass called the cladding Fiber is then jacketed in a thin transparent plastic

material called the buffer Guide to Networking Essentials, 7th Edition Cengage Learning 2016 32 Fiber-Optic Cable Guide to Networking Essentials, 7th Edition Cengage Learning 2016 33 Fiber-Optic Cable Each fiber-optic strand carries data in only one

direction Network connections consist of two or more strands Fiber-optic cable used as backbone cabling often comes in bundles of 12 or more fiber strands Even only using 2 in the backbone, running more is a good idea so that you are ready for any future expansion Some testing has shown that glass fibers can carry several terabits (1000 gigabits) per second Fiber-optic cable may one day replace copper for all types of network connections Guide to Networking Essentials, 7th Edition Cengage Learning 2016

34 Fiber-Optic Cable Guide to Networking Essentials, 7th Edition Cengage Learning 2016 35 Fiber-Optic Connectors Types of connectors:

Straight tip (ST) Straight connection (SC) Locking connection (LC) Mechanical transfer registered jack (MT-RJ) Fiber channel or ferrule connector (FC) Medium interface connector (MIC) Subminiature type A (SMA) Guide to Networking Essentials, 7th Edition Cengage Learning 2016 36

Fiber-Optic Connectors Guide to Networking Essentials, 7th Edition Cengage Learning 2016 37 Fiber-Optic Installation Somewhat more difficult and time consuming than copper media installation However, advances in connector technology is closing the gap Connectors and test equipment required for termination are still more expensive than copper There are many methods for terminating fiber-optic

cables because of the many connectors and cable types available Installation details are beyond the scope of this book Guide to Networking Essentials, 7th Edition Cengage Learning 2016 38 Fiber-Optic Cable Types Single-mode fiber (SMF) Includes a single, small-diameter fiber at the core (8 microns) Generally works with laser-based emitters Spans the longest distances Used in higher-bandwidth applications

Multimode fiber (MMF) Larger diameter fiber at the core (50 and 62.5 microns) Costs less than SMF Works with lower-power light emitting diodes (LEDs) Spans shorter distances Guide to Networking Essentials, 7th Edition Cengage Learning 2016 39

Cable-Testing Equipment Common tools for testing and troubleshooting wired networks: Cable certifier Basic cable tester Tone generator Time domain reflectometer (TDR) Multimeter Optical power meter (OPM)

Guide to Networking Essentials, 7th Edition Cengage Learning 2016 40 Wireless Networking Demand has increased considerably Many home users have turned to wireless networks Wireless networks are often used with wired networks to interconnect geographically dispersed LANs or groups of mobile users with wired servers and resources on a wired LAN (sometimes referred to as hybrid networks) Even in small networks with workstations connecting to a wireless AP or router, the AP or router usually

connects to the Internet via a wired connection to a cable modem Guide to Networking Essentials, 7th Edition Cengage Learning 2016 41 Wireless Benefits Creates temporary connections to wired networks Establishes backup or contingency connectivity for existing wired networks Extends a networks span beyond the reach of wirebased or fiber-optic cabling, especially in older buildings where rewiring might be too expensive Allows businesses to provide customers with wireless networking easily, offering a service that gets customers in and keeps them there

Enables users to roam around a corporate or college campus with their machines Guide to Networking Essentials, 7th Edition Cengage Learning 2016 42 Wireless Benefits Guide to Networking Essentials, 7th Edition Cengage Learning 2016 43 Types of Wireless Networks

Local area networks (LANs) usually provides connectivity for mobile users or across areas that couldnt otherwise be networked Extended LANs usually used to increase a LANs span beyond normal distance limitations Internet service used to bring Internet access to homes and businesses Mobile computing users communicate by using a wireless networking medium that enable them to move while remaining connected to a network Guide to Networking Essentials, 7th Edition Cengage Learning 2016 44 Wireless LAN Components

Network interface attaches to an antenna and an emitter rather than to a cable Transceiver/access point (AP) a transmitter/receiver device that must be installed to translate between wired and wireless networks Includes an antenna and a transmitter to send and receive wireless traffic but also connects to the wired side of the network Shuttles traffic back and forth between a networks wired and wireless sides Guide to Networking Essentials, 7th Edition Cengage Learning 2016 45 Wireless LAN Transmission

Signals take the form of waves in the electromagnetic (EM) spectrum The frequency of the wave forms used for communication is measured in cycles per second, usually expressed as hertz (Hz) Lower-frequency transmissions can carry less data more slowly over longer distances, and higherfrequency transmissions can carry more data faster over shorter distances Guide to Networking Essentials, 7th Edition Cengage Learning 2016 46 Wireless LAN Transmission The following are the most common frequencies for

wireless data communication: Radio 10 KHz to 300 MHz Microwave 300 MHz to 300 GHz Infrared 300 GHz to 400 THz (terahertz) Wireless LANs make use of four primary technologies for transmitting and receiving data Infrared Laser Narrowband (single-frequency) radio Spread-spectrum radio

Guide to Networking Essentials, 7th Edition Cengage Learning 2016 47 Infrared LAN Technologies Infrared (IR) wireless networks use infrared light beams to send signals between pairs of devices Works well for LAN applications due to high bandwidth Four main kinds of infrared LANs Line-of-sight networks require an unobstructed view between transmitter and receiver Reflective wireless networks broadcast signals from optical transceivers near devices to a central hub Scatter infrared networks bounce transmissions off walls and ceilings to deliver signals

Broadband optical telepoint networks provide broadband services Guide to Networking Essentials, 7th Edition Cengage Learning 2016 48 Laser-Based LAN Technologies Also require a clear line of sight between sender and receiver Subject to many of the same limitations as infrared Arent as susceptible to interference from visible light sources as infrared Guide to Networking Essentials, 7th Edition

Cengage Learning 2016 49 Narrowband Radio LAN Technologies Use low-powered, two-way radio communication Receiver and transmitter must be tuned to the same frequency to handle incoming and outgoing data Requires no line of sight between sender and receiver as long as both parties stay within the broadcast range of these devices Typically 70 meters or 230 feet Depending on the frequency, walls or other solid barriers can block signals Interference from other radio sources is possible Guide to Networking Essentials, 7th Edition

Cengage Learning 2016 50 Narrowband Radio LAN Technologies Guide to Networking Essentials, 7th Edition Cengage Learning 2016 51 Spread-Spectrum LAN Technologies Uses multiple frequencies simultaneously, improving reliability and reducing susceptibility to interference Also makes eavesdropping more difficult

Two main kinds of spread-spectrum communications Frequency hopping switches data between multiple frequencies at regular intervals Direct-sequence modulation breaks data into fixedsize segments called chips and transmits the data on several different frequencies at the same time Guide to Networking Essentials, 7th Edition Cengage Learning 2016 52 Spread-Spectrum LAN Technologies Guide to Networking Essentials, 7th Edition

Cengage Learning 2016 53 LAN Media Selection Criteria Three main media choices: UTP, fiber-optic, and wireless When choosing between media types, consider: Bandwidth Higher bandwidth means more expensive cable and higher installation costs If 40 Gbps or more, fiber-optic is the only choice Budget A typical UTP cable installation cost $100 $200 per cable run and fiber-optic might cost twice that much Wireless have no physical installation costs but you need to install access points and verify connectivity Guide to Networking Essentials, 7th Edition

Cengage Learning 2016 54 LAN Media Selection Criteria When choosing between media types, consider: Environmental considerations How electrically noisy is the environment? How important is data security? The more weight either factor has, the more likely fiber-optic or secured wireless is the right choice Span What kind of distance must the network span? Longer spans might require fiber-optic or wireless be used between buildings Strategic placement of small switches or hubs gives UTP surprising reach

Existing cable plant For an upgrade, the existing cable plant must be considered Guide to Networking Essentials, 7th Edition Cengage Learning 2016 55 LAN Media Selection Criteria Guide to Networking Essentials, 7th Edition Cengage Learning 2016 56

Summary Wired networking media come in two primary categories: copper and fiber-optic Twisted pair cabling come in shielded or unshielded varieties Twisted pair cabling components consist of connectors, patch cable, jacks, patch panels and distribution racks A structured cabling plant consists of work areas, horizontal wiring, telecommunications closets, equipment rooms, backbone cabling, and entrance facilities Guide to Networking Essentials, 7th Edition Cengage Learning 2016 57

Summary Fiber-optic uses pulses of light to represent bits and is immune to EMI, RFI and electronic eavesdropping Wireless networks can be subdivided into LANs, extended LANs, and mobile computing Components of a wireless LAN are a NIC, an antenna, and a transceiver or access point Technologies used to transmit and receive data including: infrared, laser, narrowband radio and spread-spectrum radio Networks combining fiber-optic, UTP, and wireless have become the norm Guide to Networking Essentials, 7th Edition Cengage Learning 2016

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