Physical Transmission Options

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

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

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 Based on copper wire construction 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 ofTwisted-Pair Cable

28. Properties ofTwisted-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 LANsand to connect LANs into WANs

31. Fiber-Optic Cable Advantages 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 802.12 standard Uses demand priority

39. The IEEE 802.3u Standard

40. The IEEE 802.12 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

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