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Chapter 3: Networking Media. Learning Objectives Define and understand technical terms related to cabling, including attenuation, crosstalk, shielding,

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Presentation on theme: "Chapter 3: Networking Media. Learning Objectives Define and understand technical terms related to cabling, including attenuation, crosstalk, shielding,"— Presentation transcript:

1 Chapter 3: Networking Media

2 Learning Objectives Define and understand technical terms related to cabling, including attenuation, crosstalk, shielding, and plenum Identify three major types of both network cabling and wireless network technologies Understand baseband and broadband transmission technologies and when to use each continued

3 Learning Objectives Decide what kinds of cabling and connections are appropriate for particular network environments Describe wireless transmission techniques used in LANs Describe signaling technologies for mobile computing

4 Network Cabling: Tangible Physical Media Provides a medium across which network information can travel in the form of a physical signal, whether it is a type of electrical transmission or some sequence of light pulses

5 Primary Cable Types Coaxial cable Twisted-pair (TP) cable Unshielded (UTP) Shielded (STP) Fiber-optic

6 General Cable Characteristics Bandwidth rating Maximum segment length Maximum number of segments per internetwork Maximum number of devices per segment Interference susceptibility Connection hardware Cable grade Plenum rating Bend radius Material costs Installation costs

7 Primary Techniques for Sending Signals across a Cable Baseband transmission Broadband transmission

8 Baseband Transmission Uses digital signals sent over a cable without modulation Sends binary values (0s and 1s) as pulses of different voltage levels Entire bandwidth of the cable is used to transmit a single data signal Limits any single cable strand to half- duplex transmission continued

9 Baseband Transmission Signal flow can be bi-directional Uses repeaters to restore the signal to its original strength and quality before retransmitting it to another cable

10 Broadband Transmission An analog transmission technique which may use multiple communication channels simultaneously Each data channel is represented by modulation on a particular frequency band, for which sending or receiving equipment must be tuned Signal flow is one-way only; two channels are necessary for computers to send/receive data continued

11 Broadband Transmission Uses amplifiers to detect weak signals, strengthen those signals, and then rebroadcast them Primary approaches to supporting two-way broadband communications Mid-split broadband Dual-cable broadband Offers higher bandwidths, but generally more expensive than baseband systems

12 The Importance of Bandwidth The faster the connection, the better

13 Coaxial Cable Uses a center conductor -- wrapped by an insulating layer, surrounded by a braided wire mesh and an outer jacket or sheath -- to carry high-bandwidth signals such as network traffic or broadcast television frequencies

14 Coaxial Cable Uses shielding to increase the viability of the signals that pass through a cable by absorbing stray electronic signals or fields Less susceptible to interference and attenuation than twisted-pair cabling, but more so than fiber- optic A connector must cap each end of the cable, and a terminator must screw into each end

15 Types of Coaxial Cable for Ethernet Thin Ethernet (thinnet, thinwire, cheapernet, 10Base2) Thick Ethernet (thicknet, thickwire, 10Base5)

16 Thinwire Ethernet Thin, flexible cable about 0.2 in diameter Easy to work with Relatively inexpensive to build or buy Well suited for small or constantly changing networks Uses BNC T-connectors to attach directly to networking devices and computers network adapter cards

17 Thinwire Ethernet

18 Radio Government (RG) Specifications Coaxial cable designation that reflects coaxial cables original use as a conveyance for radio frequency data and signals

19 Radio Government (RG) Specifications

20 Thinwire Ethernet Cable

21 Thickwire Ethernet Uses a rigid cable about 0.4 in diameter (frozen yellow garden hose) Rarely used except as a backbone for a new network installation (due to expense, large diameter, and lack of flexibility) Uses a vampire tap to attach a device to the cable, which in turn attaches to a transceiver; transceiver attaches to a drop or transceiver cable that plugs into an attachment unit interface (AUI)

22 Attaching to Thinwire Ethernet Cable

23 Attaching to Thickwire Ethernet Cable

24 Running Thickwire Cable

25 Thickwire Ethernet Cable

26 Coaxial Cable Characteristics Can handle moderate to serious bandwidth Supports intermediate to moderately long cable runs Relatively affordable Resistant to interference; relatively safe from electronic eavesdropping

27 Twisted-pair Cable Consists of one or more pairs of insulated strands of copper wire twisted around one another Importance of twists Improve resistance to interference Limit the influence of crosstalk

28 Types of TP Cable Unshielded twisted-pair (UTP) Contains one or more pairs of insulated wires within an enclosing insulating sheath Follows the ANSI/EIA/TIA 568 standard Prone to crosstalk Shielded twisted-pair (STP) Encloses each pair of wires within a foil shield, as well as within an enclosing insulating sheath Supports higher bandwidth over longer distances than UTP Has no set of standards

29 Types of TP Cable

30 Twisted-pair Network Cabling Schemes Commonly employ RJ-45 telephone connectors Typical elements (often in a wiring center) Punchdown blocks Patch panels Wall plates Jack couplers

31 RJ-45 Connector

32 Patch Panels and Punchdown Blocks

33 10BaseTs Networking Characteristics

34 Fiber-optic Cable Uses pulses of light sent along a light- conducting fiber at the heart of the cable to transfer information Sends data in one direction only; two cables are required to permit data exchange in both directions Consists of a slender cylinder of glass fiber(s), called the core, surrounded by a concentric layer of cladding material and then by an outer sheath

35 Fiber-optic Cable

36 Primary Types of Fiber-optic Cables Single-mode cables Include only one glass fiber at the core Cost more Work with laser-based emitters but span the longest distances Multi-mode cables Incorporate two or more glass fibers at the core Cost less Work with light emitting diodes (LEDs) but span shorter distances

37 Fiber-optic Cable Advantages Immune to interference Highly secure; eliminates possibility of electronic eavesdropping Good medium for high-bandwidth, high- speed, long-distance data transmissions

38 Fiber-optic Cable Drawbacks High cost Difficult installation

39 Fiber-optic Cable Characteristics

40 Fiber-optic Media Connectors ST (straight tip) SC (straight connection) MIC (medium interface connector) SMA (subminiature type A)

41 Cable Selection Criteria Bandwidth Budget Capacity Environmental considerations Placement Scope Span

42 Comparison of General Cable Characteristics

43 The IBM Cabling System Numeric cabling designations (Type 1 through Type 9) developed by IBM Types 2 and 9 are the most commonly used networking cables IBM cable connector is the unique feature; any two connectors are able to plug into each other

44 IBM Cable Types

45 Wireless Networking: Intangible Media Depends on transmission at some kind of electromagnetic frequency through the atmosphere to carry data transmissions from one networked device to another Appears most frequently in conjunction with wired networks

46 Capabilities of the Wireless World Creates temporary connections to existing wired networks Establishes back-up or contingency connectivity for existing wired networks Extends a networks span beyond the reach of wire- or fiber-optic-based cabling Permits certain users to roam with their machines, within certain limits

47 Commercial Applications for Wireless Networking Ready access to data for mobile professionals Delivery of network access into isolated facilities Access in environments in which layout and settings change constantly Improved customer services in busy areas Network connectivity in facilities where in-wall wiring would be impossible to install or prohibitively expensive

48 Types of Wireless Networks Local area networks (LANs) Extended LANs Mobile computing

49 Wireless LAN Applications Still necessary to attach a network interface to a computer, but the interface attaches to an antenna and an emitter rather than to a cable Requires an access point device to bridge wireless components and the wired network

50 Wireless Access Point Device

51 Wireless LAN Transmission Most common frequencies used Radio: 10 KHz to 1 GHz Microwave: 1 GHz to 500 GHz Infrared: 500 GHz to 1 THz Primary technologies used Infrared Laser Narrowband, single-frequency radio Spread-spectrum radio

52 Broadcast Medium Principles Inverse relationship between frequency and distance Direct relationship between frequency and data transfer rate and bandwidth Higher-frequency technologies often use tight-beam broadcasts and require a clear line of sight between sender and receiver to ensure correct delivery

53 Infrared LAN Technologies Use infrared light beams to send signals between pairs of devices Have high bandwidth; work well for LAN applications Require a line of sight between sender and receiver

54 Kinds of Infrared LANs Line-of-sight networks Reflective wireless networks Scatter infrared networks Broadband optical telepoint networks

55 Laser-based LAN Technologies Require a clear line of sight between sender and receiver Devices are subject to many of the same limitations as infrared but are not as subject to interference from visible light sources

56 Narrow-band, Single-frequency Radio LAN Technologies Use low-powered, two-way radio communications Require no line-of-sight between sender and receiver

57 Narrow-band, Single-frequency Wireless LAN Characteristics

58 High-powered, Single-frequency LAN Characteristics

59 Spread-spectrum LAN Technologies Address weaknesses of single-frequency communications Use multiple frequencies simultaneously; improve reliability and reduce susceptibility to interference Make eavesdropping more difficult Two main kinds Frequency-hopping Direct-sequence modulation

60 Spread-spectrum LAN Characteristics

61 Wireless Extended LAN Technologies Wireless bridge A pair of devices, typically narrow-band and tight beam, that relay network traffic from one location to another Available using spread-spectrum radio, infrared, and laser technologies Can span distances from hundreds of meters up to 25 miles

62 Wireless Extended LAN Characteristics

63 Microwave Networking Technologies Can deliver higher transmission rates than radio- based systems Transmitters and receivers must share a common, clear line of sight Usually require FCC approval and licensing More expensive than radio systems Two types Terrestrial Satellite

64 Terrestrial Microwave Uses line-of-sight communication between pairs of Earth-based transmitters and receivers to relay information Expensive; usually positioned well above ground level

65 Terrestrial Microwave LAN/WAN Characteristics

66 Satellite Microwave Uses geosynchronous satellites to send and relay signals between sender and receiver Usually leased for an exorbitant fee

67 Satellite Microwave WAN Characteristics

68 High-speed Wireless Networking Technologies IEEE Wireless Networking Standard Cellular packet radio networking Cellular Digital Packet Data (CDPD) Narrow-band sockets

69 Chapter Summary Network cabling Primary cable types Twisted-pair (unshielded and shielded) and coaxial conductive cables Fiber-optic cables Cabled network transmission schemes Broadband Baseband continued

70 Chapter Summary Wireless networking Provides cable-free LAN access Extends span of LANs Provides WAN links Supports mobile computing needs Uses a variety of electromagnetic frequency ranges Narrow-band and spread-spectrum radio Microwave Infrared Laser transmission

71 Chapter 4: Network Interface Cards

72 Learning Objectives Describe what role a network adapter card plays in networked communications Explain how network adapters prepare data for transmission, accept incoming network traffic, and control how networked communications flow Understand the variety of configurable options for network adapters and describe common settings continued

73 Learning Objectives Describe important characteristics for selecting adapter cards Recount network adapter enhancements that can improve performance Explain the role of driver software in network adapters

74 Network Interface Card Basics Crucial tasks performed by a NIC Establishes and manages the computers network connection Translates digital computer data into signals (appropriate for the network medium) for outgoing messages; translates signals into digital computer data for incoming messages

75 From Parallel to Serial, and Vice Versa A network adapter grabs outgoing transmissions from the CPU in parallel form and recasts them into their serial equivalents Parallel transmission Spreads individual bits of data across multiple, parallel data lines to transmit them simultaneously, rather than according to an ordinal and temporal sequence Serial transmission Sends each bits worth of data (or its analog equivalent) one at a time, one after another, in sequence Reverses the process for incoming messages

76 From Parallel to Serial, and Vice Versa

77 Memory is an important component on a network adapter that acts as a holding tank, or buffer Bus width Number of parallel lines that make up a bus Transceiver A device that transmits and receives network information

78 An Ethernet NIC

79 From Parallel to Serial, and Vice Versa NIC packages all the bits into orderly collections called packets and then transmits individual packets serially onto the network medium Using a network address, the NIC determines whether the computer is the appropriate recipient of data sent

80 Summary of NIC Basics Manages and controls network access Creates a physical link between a computer and a network medium Handles data transfers to and from the network and CPU and translates which forms such data can take between parallel and serial representation Interacts with the medium to determine when data transmission is permissible

81 PC Buses Specialized collections of parallel lines in a PC used to ship data between the CPU and peripheral devices Primary bus architectures ISA (Industry Standard Architecture) EISA (Extended ISA) MCA (Micro Channel Architecture) PCI (Peripheral Component Interface) AGP (Accelerated Graphics Port)

82 Primary Bus Architectures

83 Other PC Interfaces Used for Networking USB (Universal Serial Bus) FireWire (also known as IEEE 1394)

84 Principles of NIC Configuration Plug and Play architecture Manual configuration involves working with three types of PC settings: Interrupt request line (IRQ) Base I/O port Base memory address Two ways of setting hardware configurations Jumper blocks DIP (dual inline package) switches

85 Setting Hardware Configurations

86 Interrupt Request Lines (IRQs) Any of 16 unique signal lines between the CPU and the bus slots on a PC Define the mechanism whereby a peripheral device can stake a claim on the PCs attention

87 Most Common PC IRQs

88 Base I/O Port The memory address where the CPU and an adapter check for messages that they leave for each other Must be unique

89 Common NIC Base I/O Port Assignments

90 Base Memory Address (membase) Starting address for NICs buffer space Bounded by size of the buffers extent

91 Making the Network Attachment Importance of matching the adapter you choose with the medium to which it must attach When a network adapter supports more than one media type, selecting the one to use becomes another configuration option Normally involves changing DIP switches or shifting a jumper block

92 Choosing Network Adapters for Best Performance Identify the physical characteristics the card must match Consider other hardware-enhancement options to help improve overall network performance

93 Hardware-enhancement Options Direct Memory Access (DMA) Shared adapter memory Shared system memory Bus mastering RAM buffering On-board co-processors Security features Traffic management or grooming Improved fault tolerance

94 Considerations when Purchasing a Network Adapter Bus width Bus type Memory transfer Special features required Bus mastering Vendor factors

95 Special-purpose NICs Interfaces for wireless networks Interfaces for diskless workstations (a.k.a. thin clients), which must access the network to load an operating system as they boot up Support remote boot or remote initial program load

96 Wireless Adapter Components Indoor antenna and antenna cable Software to enable the adapter to work with a particular network environment Diagnostic software to check initial installation or to troubleshoot thereafter Installation software

97 Remote Boot Adapters Some include a chip socket for Boot PROM (programmable read-only memory) Once a diskless workstation finishes booting, it can use the network to read and write additional needed data

98 Driver Software Permits a network adapter to communicate with a computers operating system Recommendations Ensure that a valid driver is available for your operating system before purchasing an adapter Obtain the latest driver version before installing a network adapter Make regular driver upgrades part of your network maintenance routine

99 Major Driver Vendor Standards NDIS (Network Device Interface Specification) WDM (Win32 Driver Model) ODI (Open Data-link Interface)

100 Installing a New Network Connection

101 Chapter Summary What a network interface does and how it works How to install and configure network adapters How to select an appropriate adapter for your situation

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