1. Physical Transmission Options
Chapter 3

2. Learning Objectives
Describe the functions of the principal networking standards organizations
Describe the various kinds of network media, including coaxial, twisted-pair, and fiber-optic media, and identify which to use in a given network configuration
Describe the basics of wireless communications
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3. Learning Objectives
Discuss high-speed technologies for twisted-pair and fiber-optic cable
Compare packet and cell implementations and the interfaces used by each
Explain WAN carrier types for point-to-point, T-carrier, SONET, ISDN, and wireless topologies

4. Network Standards Organizations
Help ensure that equipment from different manufacturers can be integrated
Key role in growth of networks and network equipment

5. Network Standards Organizations
ANSI
American National Standards Institute
IEEE
Institute of Electrical and Electronics Engineers
ITU
International Telecommunications Union
ISO
International Organization for Standardization
ISOC
Internet Society
IETF
Internet Society and the Internet Engineering Task Force
EIA/TIA
Electronic Industries Alliance and the Telecommunications Industry Association

6. ANSI Established in 1918 Standards for wide range of products
Computer industry standards:
Screen-display attributes
Digital telecommunications
Fiber-optic cable transmissions

7. IEEE
International organization of scientists, engineers, technicians, and educators
Develops networking standards for network cabling and data transmissions
802 standards

8. ITU Sets telecommunications standards for modem and WAN communications
International organization

9. ISO Establishes communications and networking standards
Known for its contributions to network protocol standards
International organization

10. ISOC and IETF
ISOC
Sponsors conferences and publications and oversees Internet standards
Nonprofit international organization
Supporter of Internet Corporation for Assigned Names and Numbers (ICANN)
IETF
Arm of ISOC that works on Internet-related technical issues such as routing

11. EIA and TIA
EIA
Network cabling standards and electrical interface standards
TIA
Standards body within EIA that develops telecommunications and cabling standards
Structured wiring, horizontal cabling, backbone cabling
Wiring closet configurations

12. Physical Transmission Options for LANs and WANs
Media types
Interface types
WAN carrier types

13. Communications Media Types
Coaxial cable
Based on copper wire construction
Twisted-pair cable
Fiber-optic cable
Glass (usually), or plastic
Wireless technologies
Radio or microwaves

14. Factors to Consider When Choosing a Medium
Data transfer speed
Use in specific network topologies
Distance requirements
Cable and cable component costs
Additional network equipment that might be required
Flexibility and ease of installation
Immunity to interference from outside sources
Upgrade options

15. Coaxial Cable Copper core surrounded by insulation
Insulation surrounded by another conducting material, which is covered by an outer insulating material
Types
Thick coax cable (thickwire or thicknet)
Thin coax cable

16. Thick Coax Cable

17. Connecting to Thick Coax Cable

18. Thick Coax Cable Properties

19. Thin Coax Cable
Attaches to a bayonet nut connector (BNC)

20. Thin Coax Cable Properties

21. Twisted-Pair Cable
Flexible cable that contains pairs of insulated copper wires that are twisted together for reduction of EMI and RFI and covered with an outer insulating jacket
Typically used on LANs to bring network to desktop
Connects to network devices with RJ-45 plug-in connectors

22. Twisted-Pair Cable

23. Types of Twisted-Pair Cable
Shielded twisted-pair (STP) cable
Pairs of insulated wires that are twisted together, surrounded by shielding material for added EMI and RFI protection, all inside a protective jacket
Unshielded twisted-pair (UTP) cable
No shielding material between pairs of insulated wires twisted together and cable’s outside jacket

24. STP and UTP Cable

25. Twisted-Pair Cable Standards

26. Twisted-Pair Cable Types for Token Ring Applications

27. Properties of Twisted-Pair Cable

28. Properties of Twisted-Pair Cable

29. Token Ring Design Specs

30. Fiber-Optic Cable
Glass or plastic fiber core inside protective cladding material, covered by plastic PVC outer jacket
Usually uses infrared light for signal transmission
Used to connect networks on LANs and to connect LANs into WANs

31. Fiber-Optic Cable Advantages Disadvantages
Able to sustain transmissions over long distances due to high bandwidth and low attenuation
No EMI or RFI problems
Difficult to place unauthorized taps
Disadvantages
Very fragile
Relatively expensive
Requires specialized training to install

32. Fiber-Optic Cable Modes
Single-mode
Multimode
Step index
Graded index

33. Properties of Single-Mode Fiber-Optic Cable

34. Properties of Multimode Fiber-Optic Cable

35. Hybrid Fiber/Coax (HFC) Cables
Single cable sheath containing a combination of fibers and copper cables in different combinations for different implementations
Full HFC system can deliver:
Plain Old Telephone Service (POTS)
Up to 37 analog TV channels
Up to 188 digital TV channels
Up to 464 digital point channels
High-speed, two-way digital data link for PCs

37. High-Speed Technologies for Twisted-Pair and Fiber-Optic Cable
Fast Ethernet
Gigabit Ethernet
10 Gigabit Ethernet

38. Fast Ethernet
Ethernet communications at speeds up to 100 Mbps as defined under the:
802.3u standard
More commonly used
Based on CSMA/CD
standard
Uses demand priority

39. The IEEE 802.3u Standard

40. The IEEE Standard

41. Gigabit Ethernet Provides even faster network communications
Particularly important for backbone architectures

42. Gigabit Ethernet Specifications

43. 10 Gigabit Ethernet
Positioned to become popular LAN and WAN alternative; promises very high-speed communications
Does not use CSMA/CD as the transmission method

44. 10 Gigabit Ethernet Specifications

45. Wireless Communications
Transmit signal through air or atmosphere
Good alternative when cable is not physically or economically feasible
Can experience interference from other signals using same media
Types available
Radio waves and infrared signals (short-distance)
Microwave and satellite (long-distance)

46. Data Interface Types
Data is transported on networks in packets or cells
Each type of transport requires specialized interfaces for physical network connections

47. Packet Transmission Used at lower bandwidth installations
Most commonly used to carry data on LANs
Requires transceivers, appropriate cable interfaces, and network drivers
Timing information for multiple packet transfers
Packets are physically transported on a network via network interface card (NIC)
Packets contain variable amount of data in multiples of eight bits

48. Generic Packet Format
Format determined by protocol used on network

49. Cell Transmission Used for very high-bandwidth implementations
Enables high-speed communications between LANs and on WANs
Requires transceivers, appropriate cable interfaces, and network drivers
Cells contain fixed amount of data formatted to be transmitted at high speeds
Primarily used in Asynchronous Transfer Mode (ATM)

50. Generic Cell Format

51. WAN Carrier Types Point-to-point T-carrier
SONET (synchronous optical network)
ISDN (Integrated Services Digital Network)

52. Point-to-Point
Two stations communicate through public dial-up or leased lines

53. T-Carrier Normally available through telecommunications carriers
Typically come out of channel banks at telecommunications company
Five types of channel banks: D-1 through D-4 and Digital Carrier Trunk

54. T-Carrier
DS-x
Relates to OSI Physical layer, which influences electrical transmission
T-x
Relates to Data Link layer, which addresses protocol and data-formatting issues

55. T-Carrier Switching Techniques
Time division multiple access (TDMA)
Combination of TDMA and statistical multiple access
Fast packet technology
Multiplexer

56. T-Carrier Connections
Digital access cross-connects (DACS)
DS-1 (T-1) connectivity
Combined DS-0 or fractional connectivity
Single DS-0 channels
Combination channel service unit (CSU) and data service unit (DSU)

57. Connecting with a CSU/DSU

58. SONET
Uses single-mode and multimode fiber-optic cable and communications based on T-3 services
Allows for high-speed data transmission, enabling delivery of voice, data, and video
Converts electrical-based STS-x signal to optical-based signal (optical carrier or OC)

59. SONET STS-1 Frame

60. SONET STS-x and OC-x Transmission Rates

61. ISDN
WAN technology for delivering voice, data, and video services over telephone lines, using a combination of channels
Physical line is a POTS or T-1 (twisted-pair or fiber-optic), with ISDN equipment at the telco and customer
Methods of placing digital signals on network
Time-compression multiplexing (TCM)
Echo cancellation

62. Chapter Summary
Standards organizations that influence network transmission techniques and media
Communications cabling media
High-speed technologies
Fast Ethernet
Gigabit Ethernet
10 Gigabit Ethernet
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63. Chapter Summary
How data is transported by using packets and cell formats
Specialized carrier methods
Point-to-point
T-carrier
SONET
ISDN
Wireless transmission