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 Fiber-optic
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 cable’s 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. 10BaseT’s 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 network’s 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 computer’s 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 bit’s 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. From Parallel to Serial, and Vice Versa
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 PC’s 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 NIC’s buffer space
Bounded by size of the buffer’s 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 computer’s 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