Gilbert Held is an internationally recognized author and lecturer who specializes in the applications of computer and communications technology. With over 30 years ofexperience in managing communications networks, he conducts seminars on topics that include LAN/WAN internetworking, data compression, and PC hardware and software. Held has written numerous books on computers and communications technology and has been recognized for his technical excellence in writing.

• Preface xixAcknowledgements xxi1 Communications in a Modern Society 11.1 Applications 11.1.1 Data collection 21.1.2 Transaction processing 31.1.3 Conversational time sharing 51.1.4 Remote job entry 71.1.5 Message switching 71.1.6 Value-added carriers and electronic mail 81.1.7 office automation 121.1.8 Electronic commerce 141.1.9 Satellite transmission 161.2 Constraints 161.2.1 Throughput 171.2.2 Response time 181.2.3 Bandwidth 181.2.4 Economics 191.3 Emerging Trends 191.4 Review Questions 202 Basic Telegraph and Telephone Operations 232.1 Evolution of Communications 232.2 Telegraphy 242.2.1 Operation 242.2.2 Morse code 262.2.3 Morse code limitations 272.2.4 Start-stop signaling and the Baudot code 282.2.5 Bits and codes 292.3 Telephony 322.3.1 Principle of operation 322.3.2 Sound wave conversion 342.3.3 The basic telephone connection 362.3.4 Switchboards and central offices 372.3.5 Numbering plans 392.3.6 Geographic calling areas and network routing 402.3.7The world numbering plan 432.4 Review Questions 433 Basic Circuit Parameters, Measurement Units and Media Overview 473.1 Basic Circuit Parameters 473.1.1 Frequency and bandwidth 473.1.2 The telephone channel passband 493.2 Measurement Units 503.2.1 Power ratios 503.2.2 Signal-to-noise ratio 523.2.3 Reference points 543.3 Media Overview 563.3.1 Twisted-pair cable 563.3.2 Coaxial cable 613.3.3 Microwave 633.3.4 Fiber-optic transmission 643.4 Channel Capacity 673.4.1 Bit versus baud 673.4.2 Nyquist relationship 673.4.3 Shannon's law 683.5 Structured Wiring 693.5.1 The wiring closet 693.5.2 The EIA/TIA-568 standard 693.6 Review Questions 724 Fundamental Data Transmission Concepts 754.1 Analog Line Connections 754.1.1 The analog switched line 764.1.2 Analog leased line 794.1.3 Dedicated line 824.1.4 Switched network vs leased line economics 834.2 Types of Service and Transmission Devices 844.2.1 Digital repeaters 854.2.2 Modems 864.2.3 Acoustic couplers 874.2.4 Analog facilities 894.2.5 Digital facilities 934.2.6 Digital signaling 934.2.7Representative AT&T digital offerings 964.3 Transmission Mode 984.3.1 Simplex transmission 984.3.2 Half-duplex transmission 994.3.3 Full-duplex transmission 1004.3.4 Terminal and mainframe computer operating modes 1014.4 Transmission Techniques 1034.4.1 Asynchronous transmission 1034.4.2 Synchronous transmission 1054.5 Types of Transmission 1064.6 Wide Area Network Transmission Structures 1074.6.1 Mainframe computer-based network structure 1084.6.2 LAN network structure 1094.6.3 LAN internetworking structure 1104.7Line Discipline 1114.8 Transmission Rate 1134.8.1 Analog service 1134.8.2 Digital service 1144.9 Transmission Codes 1154.9.1 Morse code 1154.9.2 Baudot code 1164.9.3 BCD code 1164.9.4 Extended binary-coded decimal interchange code (EBCDIC) 1164.9.5 ASCII code 1184.10 Review Questions 1225 Terminals, Workstations and WAN and LAN Networking Overview 1255.1 Terminals 1265.1.1 Interactive terminal classi®cation 1265.1.2 Terminal evolution 1275.2 Workstations and Other LAN Components 1415.2.1 Network interface card 1415.2.2 Hubs 1425.2.3 File server 1435.2.4 Print server 1455.2.5 Other types of servers 1465.3 Wide Area Networking Overview 1465.3.1 Multiplexing and data concentration 1465.3.2 Front-end processor 1515.3.3 Network configurations 1515.4 Local Area Networking Overview 1525.4.1 Repeaters 1535.4.2 Bridges 1535.4.3 Routers 1545.4.4 Gateways 1555.5 Review Questions 1576 Representative Standards Organizations: the OSI Reference Model 1596.1 National Standards Organizations 1606.1.1 American National Standards Institute (ANSI) 1606.1.2 Electronic Industries Association (EIA) 1616.1.3 Federal Information Processing Standards (FIPS) 1636.1.4 Institute of Electrical and Electronic Engineers (IEEE) 1636.1.5 British Standards Institution (BSI) 1646.1.6 Canadian Standards Association (CSA) 1646.2 International Standards Organizations 1646.2.1 International Telecommunications Union (ITU) 1646.2.2 International Standards Organization (ISO) 1656.3 De facto Standards 1676.3.1 AT&T compatibility 1686.3.2 Cross-licensed technology 1696.3.3 Bellcore/Telcordia Technology 1696.3.4 Internet standards 1706.4 The OSI Reference Model 1716.4.1 Layered architecture 1726.4.2 OSI layers 1736.4.3 Data flow 1766.5 IEEE 802 Standards 1776.5.1 802 committees 1776.5.2 Data link subdivision 1796.6 Review Questions 1807 The Physical Layer, Cables, Connectors, Plugs and Jacks 1837.1 DTE/DCE Interfaces 1847.1.1 Connector overview 1867.1.2 RS-232-C/D 1887.1.3 Differential signaling 1987.1.4 RS- 449 2007.1.5 V. 35 2027.1.6 RS-366-A  2037.1.7 X.21 and X. 20 2047.1.8 X.21 bis 2077.1.9 RS- 530 2077.1.10 High Speed Serial Interface 2987.1.11 High Performance Parallel Interface 2147.1.12 Universal Serial Bus 2167.1.13 IEEE 1394 (FireWire) 2187.2 Cables and Connectors 2227.2.1 Twisted-pair cable 2227.2.2 Low-capacitance shielded cable 2237.2.3 Ribbon cable 2237.2.4 The RS-232 null modem 2237.2.5 RS-232 cabling tricks 2257.3 Plugs and Jacks 2267.3.1 Connecting arrangements 2287.3.2 Telephone options 2307.3.3 Ordering the business line 2317.3.4 LAN connectivity 2327.4 Review Questions 2338 Basic Transmission Devices: Line Drivers, Modems, and Service Units 2358.1 Line Drivers 2368.1.1 Direct connection 2368.1.2 Using line drivers 2398.2 Modem Operations 2438.2.1 The modulation process 2438.2.2 Bps vs. baud 2468.2.3 Voice circuit parameters 2468.2.4 Combined modulation techniques 2478.2.5 Mode of transmission 2538.2.6 Transmission techniques 2548.2.7 Modem classiffication 2558.2.8 Limited-distance modems 2568.2.9 Line-type operations 2578.2.10 Reverse and secondary channels 2578.2.11 Equalization 2588.2.12 Synchronization 2608.2.13 Multiport capability 2608.2.14 Security capability 2618.2.15 Multiple speed selection capability 2618.2.16 Voice/data capability 2628.2.17Modem handshaking 2628.2.18 Self-testing features 2638.2.19 Modem indicators 2658.2.20 Modern operations and compatibility 2658.3 Intelligent Modems 2898.3.1 Hayes command set modems 2898.3.2 Key intelligent modem features 2968.3.3 Microcom Networking Protocol (MNP) 3028.3.4 Data compression 3068.3.5 MNP Class 5 compression 3068.3.6 MNP Class 7enhanced data compression 3088.3.7V.42bis 3118.4 Broadband Modems 3128.4.1 Telephone and cable TV infrastructure 3138.4.2 Cable modems 3178.4.3 DSL modems 3248.5 Service Units 3308.5.1 The DSU 3318.5.2 The CSU 3318.6 Review Questions 3329 Regulators and Carriers 3359.1 Regulators 3369.1.1 US regulatory evolution 3369.1.2 International regulatory authorities 3429.2 Carrier Offerings 3439.2.1 AT&T system evolution 3439.2.2 The Bell system 3459.2.3 The regional Bell operating companies 3469.2.4 AT&T service offerings 3499.2.5 Regional Bell operating company offerings 3559.3 ATM Overview 3569.4 Review Questions 35710 Transmission Errors: Causes, Measurements and Correction Methods 35910.1 Causes of Transmission Errors 35910.2 Performance Measurements 36010.2.1 Bit error rate 36010.2.2 Bit error rate tester 36010.2.3 BERT time 36210.2.4 Performance classiffications 36210.2.5 Block error rate testing 36410.2.6 Error-free second testing 36510.3 Error Detection and Correction Techniques 36510.3.1 Asynchronous transmission 36510.3.2 Synchronous transmission 37010.4 Review Questions 37411 The WAN Data Link Layer 37711.1 Terminal and Data Link Protocols: Characteristics and Functions 37811.1.1 Transmission sequence 37911.1.2 Error control 37911.2 Types of Protocol 38011.2.1 Teletypewriter protocols 38011.2.2 PC file transfer protocols 38511.2.3 Bisynchronous protocols 39511.2.4. Digital Data Communications Message Protocol (DDCMP) 40011.2.5 Bit-oriented line control procedures 40211.3 Review Questions 40712 Increasing WAN Line Utilization 40912.1 Multiplexers 41012.1.1 Evolution 41012.1.2 Device support 41012.1.3 Multiplexing techniques 41112.2 Control Units 43912.2.1 Control unit concept 44012.2.2 Attachment methods 44012.2.3 Unit operation 44212.2.4 Breaking the closed system 44312.3 Review Questions 44513 Local Area Networks 44913.1 Origin 44913.2 Comparison with WANs 45013.2.1 Geographical area 45013.2.2 Data transmission and error rates 45013.2.3 Ownership 45113.2.4 Regulation 45113.2.5 Data routing and topology 45113.2.6 Type of information carried 45213.3 Utilization Benefits 45213.3.1 Peripheral sharing 45313.3.2 Common software access 45313.3.3 Electronic mail 45313.3.4 Gateway access to mainframes 45313.3.5 Internet access 45313.3.6 Virtual private network operations 45413.4 Technological Characteristics 45413.4.1 Topology 45413.4.2 Comparison of topologies 45613.4.3 Signaling methods 45713.4.4 Transmission medium 46013.4.5 Access methods 46013.5 Ethernet Networks 46513.5.1 Original network components 46513.5.2 IEEE 802.3 networks 46813.5.3 Frame composition 49013.5.4 Media access control overview 49513.5.5 Logical link control overview 49513.5.6 Other Ethernet frame types 49813.6 Token-Ring 50413.6.1 Topology 50413.6.2 Redundant versus non-redundant main ring paths 50613.6.3 Cabling and device restrictions 50713.6.4 Constraints 51013.6.5 High speed Token-Ring 51413.6.6 Transmission formats 51513.6.7Medium access control 52413.6.8 Logical link control 52713.7Review Questions 52814 Basic LAN Internetworking 53114.1 Bridge Operations 53114.1.1 Types of bridge 53114.1.2 Network utilization 54414.2 The Switching Hub 54614.2.1 Basic components 54614.2.2 Delay times 54714.2.3 Key advantages of use 54914.2.4 Switching techniques 54914.2.5 Port address support 55314.2.6 Switching architecture 55614.2.7High-speed port operations 55714.2.8 Summary 55814.3 Router Operations 55814.3.1 Basic operation and use of routing tables 55914.3.2 Networking capability 56014.3.3 Communication, transport and routing protocols 56114.3.4 Router classiffications 56314.3.5 Routing protocols 56614.4 Review Questions 57515 Digital Transmission Systems and Equipment 57715.1 The T and E Carriers 57815.1.1 Channel banks 57815.2 T1 Multiplexers 59615.2.1 Waveform-based voice digitization modules 59715.2.2 Vocoding 59815.2.3 Hybrid coding 60115.2.4 T1 multiplexer employment 60215.3 The T3 Carrier 60515.3.1 T3 circuit types 60615.3.2 Evolution 60615.3.3 T3 framing 60915.4 DDS, ASDS and KiloStream facilities 61515.4.1 Applications 61615.4.2 ASDS 61615.4.3 KiloStream service 61715.5 Integrated Services Digital Network (ISDN) 61915.5.1 Concept behind ISDN 61915.5.2 ISDN architecture 62015.5.3 Network characteristics 62115.5.4 ISDN layers 62515.6 Review Questions 62816 Network Architecture 63116.1 SNA Overview 63216.1.1 SNA elements 63416.1.2 System Service Control Point (SSCP) 63416.1.3 Network nodes 63416.1.4 The physical unit 63516.1.5 The logical unit 63516.1.6 SNA network structure 63516.1.7Types of physical unit 63716.1.8 Multiple domains 63716.1.9 SNA layers 63916.1.10 SNA developments 64116.1.11 SNA sessions 64116.2 Advanced Peer-to-Peer Networking (APPN) 64416.2.1 APPC concepts 64416.2.2 APPN architecture 64516.2.3 Operation 64616.3 TCP/IP 64916.3.1 The rise of the Internet 65016.3.2 The TCP/IP protocol suite 65116.3.3 Applications 65316.3.4 TCP/IP communications 66316.3.5 The Internet Protocol (IP) 66416.3.6 Domain Name Service 67916.4 Internetworking 68116.4.1 SNA gateway operations 68216.4.2 Supporting multiple protocols 69016.4.3 Data Link Switching 69316.5 Review Questions 69417 Packet Networks 69717.1 Packet Switching Overview 69817.2 X.25 Networks 70017.2.1 Development period 70017.2.2 Need for PADs 70017.2.3 X.25 layers 70517.2.4 Methods of connection 70817.2.5 Utilization costs 70917.2.6 Tymnet 71117.2.7 Network information 71317.2.8 Features 71317.2.9 Protocol conversion 71517.2.10 LAN interconnectivity 71617.3 Frame Relay 71717.3.1 Comparison to X. 25 71717.3.2 Standards 71917.3.3 Network access 72017.3.4 Frame construction 72117.3.5 Service parameters 72917.3.6 FRAD features 73417.3.7 Voice over Frame Relay 74017.4 Review Questions 74518 Communications Software 74918.1 Terminal Emulation Software Features 74918.1.1 Hardware utilization 75218.1.2 Software utilization 75318.1.3 Operational consideration 75418.1.4 Documentation 75718.1.5 Dialing 75718.1.6 Transmission 76218.1.7Performance efficiency 76618.1.8 Performance flexibility 77018.1.9 Security performance 77218.2 Terminal Emulation Program Examination 77418.2.1 Procomm Plus for Windows 77518.2.2 HyperTerminal 77718.2.3 IBM PC/ 3270 78018.3 Web Browsers 78318.3.1 Microsoft Internet Explorer 78418.3.2 LAN operation 78818.4 Review Questions 78919 Fiber-Optic, Satellite and Wireless Terrestrial Communications 79119.1 Fiber-Optic Transmission Systems 79219.1.1 System components 79219.1.2 Transmission advantages 79919.1.3 Limitations of use 80119.1.4 Utilization economics 80219.1.5 Carrier utilization 80519.1.6 SONET 80619.2 Satellite Communications Systems 81019.2.1 Operation overview 81019.2.2 Satellite access 81019.2.3 Very small aperture terminal (VSAT) 81219.2.4 Low earth orbit satellites 81219.3 Wireless Terrestrial Communications 81419.3.1 Cellular communications 81419.3.2 Wireless LANs 82019.4 Review Questions 82120 Evolving Technologies 82320.1 ATM 82320.1.1 Cell size 82320.1.2 Scalability 82420.1.3 Transparency 82520.1.4 Traffic classiffication 82520.2 The ATM Protocol Stack 82520.2.1 ATM Adaptation Layer 82520.2.2 The ATM Layer 82620.2.3 Physical Layer 82720.3 ATM Operation 82720.3.1 Components 82720.3.2 Network Interfaces 82920.3.3 The ATM cell header 83020.3.4 ATM connections and cell switching 83320.4 Virtual Private Networking 83520.4.1 Rationale for use 83620.4.2 Reliability 83720.4.3 Problem areas 83720.5 Review Questions 838Index 841

"...designed to provide a solid foundation on how data communications systems operate, why, where, and when certain types of equipment should be networked together, and the role of evolving communications technology." (SciTech Book News, Vol. 25, No. 4, December 2001)

Gilbert Held is an internationally recognized author and lecturer who specializes in the applications of computer and communications technology. With over 30 years ofexperience in managing communications networks, he conducts seminars on topics that include LAN/WAN internetworking, data compression, and PC hardware and software. Held has written numerous books on computers and communications technology and has been recognized for his technical excellence in writing.

• Preface xixAcknowledgements xxi1 Communications in a Modern Society 11.1 Applications 11.1.1 Data collection 21.1.2 Transaction processing 31.1.3 Conversational time sharing 51.1.4 Remote job entry 71.1.5 Message switching 71.1.6 Value-added carriers and electronic mail 81.1.7 office automation 121.1.8 Electronic commerce 141.1.9 Satellite transmission 161.2 Constraints 161.2.1 Throughput 171.2.2 Response time 181.2.3 Bandwidth 181.2.4 Economics 191.3 Emerging Trends 191.4 Review Questions 202 Basic Telegraph and Telephone Operations 232.1 Evolution of Communications 232.2 Telegraphy 242.2.1 Operation 242.2.2 Morse code 262.2.3 Morse code limitations 272.2.4 Start-stop signaling and the Baudot code 282.2.5 Bits and codes 292.3 Telephony 322.3.1 Principle of operation 322.3.2 Sound wave conversion 342.3.3 The basic telephone connection 362.3.4 Switchboards and central offices 372.3.5 Numbering plans 392.3.6 Geographic calling areas and network routing 402.3.7The world numbering plan 432.4 Review Questions 433 Basic Circuit Parameters, Measurement Units and Media Overview 473.1 Basic Circuit Parameters 473.1.1 Frequency and bandwidth 473.1.2 The telephone channel passband 493.2 Measurement Units 503.2.1 Power ratios 503.2.2 Signal-to-noise ratio 523.2.3 Reference points 543.3 Media Overview 563.3.1 Twisted-pair cable 563.3.2 Coaxial cable 613.3.3 Microwave 633.3.4 Fiber-optic transmission 643.4 Channel Capacity 673.4.1 Bit versus baud 673.4.2 Nyquist relationship 673.4.3 Shannon's law 683.5 Structured Wiring 693.5.1 The wiring closet 693.5.2 The EIA/TIA-568 standard 693.6 Review Questions 724 Fundamental Data Transmission Concepts 754.1 Analog Line Connections 754.1.1 The analog switched line 764.1.2 Analog leased line 794.1.3 Dedicated line 824.1.4 Switched network vs leased line economics 834.2 Types of Service and Transmission Devices 844.2.1 Digital repeaters 854.2.2 Modems 864.2.3 Acoustic couplers 874.2.4 Analog facilities 894.2.5 Digital facilities 934.2.6 Digital signaling 934.2.7Representative AT&T digital offerings 964.3 Transmission Mode 984.3.1 Simplex transmission 984.3.2 Half-duplex transmission 994.3.3 Full-duplex transmission 1004.3.4 Terminal and mainframe computer operating modes 1014.4 Transmission Techniques 1034.4.1 Asynchronous transmission 1034.4.2 Synchronous transmission 1054.5 Types of Transmission 1064.6 Wide Area Network Transmission Structures 1074.6.1 Mainframe computer-based network structure 1084.6.2 LAN network structure 1094.6.3 LAN internetworking structure 1104.7Line Discipline 1114.8 Transmission Rate 1134.8.1 Analog service 1134.8.2 Digital service 1144.9 Transmission Codes 1154.9.1 Morse code 1154.9.2 Baudot code 1164.9.3 BCD code 1164.9.4 Extended binary-coded decimal interchange code (EBCDIC) 1164.9.5 ASCII code 1184.10 Review Questions 1225 Terminals, Workstations and WAN and LAN Networking Overview 1255.1 Terminals 1265.1.1 Interactive terminal classi®cation 1265.1.2 Terminal evolution 1275.2 Workstations and Other LAN Components 1415.2.1 Network interface card 1415.2.2 Hubs 1425.2.3 File server 1435.2.4 Print server 1455.2.5 Other types of servers 1465.3 Wide Area Networking Overview 1465.3.1 Multiplexing and data concentration 1465.3.2 Front-end processor 1515.3.3 Network configurations 1515.4 Local Area Networking Overview 1525.4.1 Repeaters 1535.4.2 Bridges 1535.4.3 Routers 1545.4.4 Gateways 1555.5 Review Questions 1576 Representative Standards Organizations: the OSI Reference Model 1596.1 National Standards Organizations 1606.1.1 American National Standards Institute (ANSI) 1606.1.2 Electronic Industries Association (EIA) 1616.1.3 Federal Information Processing Standards (FIPS) 1636.1.4 Institute of Electrical and Electronic Engineers (IEEE) 1636.1.5 British Standards Institution (BSI) 1646.1.6 Canadian Standards Association (CSA) 1646.2 International Standards Organizations 1646.2.1 International Telecommunications Union (ITU) 1646.2.2 International Standards Organization (ISO) 1656.3 De facto Standards 1676.3.1 AT&T compatibility 1686.3.2 Cross-licensed technology 1696.3.3 Bellcore/Telcordia Technology 1696.3.4 Internet standards 1706.4 The OSI Reference Model 1716.4.1 Layered architecture 1726.4.2 OSI layers 1736.4.3 Data flow 1766.5 IEEE 802 Standards 1776.5.1 802 committees 1776.5.2 Data link subdivision 1796.6 Review Questions 1807 The Physical Layer, Cables, Connectors, Plugs and Jacks 1837.1 DTE/DCE Interfaces 1847.1.1 Connector overview 1867.1.2 RS-232-C/D 1887.1.3 Differential signaling 1987.1.4 RS- 449 2007.1.5 V. 35 2027.1.6 RS-366-A  2037.1.7 X.21 and X. 20 2047.1.8 X.21 bis 2077.1.9 RS- 530 2077.1.10 High Speed Serial Interface 2987.1.11 High Performance Parallel Interface 2147.1.12 Universal Serial Bus 2167.1.13 IEEE 1394 (FireWire) 2187.2 Cables and Connectors 2227.2.1 Twisted-pair cable 2227.2.2 Low-capacitance shielded cable 2237.2.3 Ribbon cable 2237.2.4 The RS-232 null modem 2237.2.5 RS-232 cabling tricks 2257.3 Plugs and Jacks 2267.3.1 Connecting arrangements 2287.3.2 Telephone options 2307.3.3 Ordering the business line 2317.3.4 LAN connectivity 2327.4 Review Questions 2338 Basic Transmission Devices: Line Drivers, Modems, and Service Units 2358.1 Line Drivers 2368.1.1 Direct connection 2368.1.2 Using line drivers 2398.2 Modem Operations 2438.2.1 The modulation process 2438.2.2 Bps vs. baud 2468.2.3 Voice circuit parameters 2468.2.4 Combined modulation techniques 2478.2.5 Mode of transmission 2538.2.6 Transmission techniques 2548.2.7 Modem classiffication 2558.2.8 Limited-distance modems 2568.2.9 Line-type operations 2578.2.10 Reverse and secondary channels 2578.2.11 Equalization 2588.2.12 Synchronization 2608.2.13 Multiport capability 2608.2.14 Security capability 2618.2.15 Multiple speed selection capability 2618.2.16 Voice/data capability 2628.2.17Modem handshaking 2628.2.18 Self-testing features 2638.2.19 Modem indicators 2658.2.20 Modern operations and compatibility 2658.3 Intelligent Modems 2898.3.1 Hayes command set modems 2898.3.2 Key intelligent modem features 2968.3.3 Microcom Networking Protocol (MNP) 3028.3.4 Data compression 3068.3.5 MNP Class 5 compression 3068.3.6 MNP Class 7enhanced data compression 3088.3.7V.42bis 3118.4 Broadband Modems 3128.4.1 Telephone and cable TV infrastructure 3138.4.2 Cable modems 3178.4.3 DSL modems 3248.5 Service Units 3308.5.1 The DSU 3318.5.2 The CSU 3318.6 Review Questions 3329 Regulators and Carriers 3359.1 Regulators 3369.1.1 US regulatory evolution 3369.1.2 International regulatory authorities 3429.2 Carrier Offerings 3439.2.1 AT&T system evolution 3439.2.2 The Bell system 3459.2.3 The regional Bell operating companies 3469.2.4 AT&T service offerings 3499.2.5 Regional Bell operating company offerings 3559.3 ATM Overview 3569.4 Review Questions 35710 Transmission Errors: Causes, Measurements and Correction Methods 35910.1 Causes of Transmission Errors 35910.2 Performance Measurements 36010.2.1 Bit error rate 36010.2.2 Bit error rate tester 36010.2.3 BERT time 36210.2.4 Performance classiffications 36210.2.5 Block error rate testing 36410.2.6 Error-free second testing 36510.3 Error Detection and Correction Techniques 36510.3.1 Asynchronous transmission 36510.3.2 Synchronous transmission 37010.4 Review Questions 37411 The WAN Data Link Layer 37711.1 Terminal and Data Link Protocols: Characteristics and Functions 37811.1.1 Transmission sequence 37911.1.2 Error control 37911.2 Types of Protocol 38011.2.1 Teletypewriter protocols 38011.2.2 PC file transfer protocols 38511.2.3 Bisynchronous protocols 39511.2.4. Digital Data Communications Message Protocol (DDCMP) 40011.2.5 Bit-oriented line control procedures 40211.3 Review Questions 40712 Increasing WAN Line Utilization 40912.1 Multiplexers 41012.1.1 Evolution 41012.1.2 Device support 41012.1.3 Multiplexing techniques 41112.2 Control Units 43912.2.1 Control unit concept 44012.2.2 Attachment methods 44012.2.3 Unit operation 44212.2.4 Breaking the closed system 44312.3 Review Questions 44513 Local Area Networks 44913.1 Origin 44913.2 Comparison with WANs 45013.2.1 Geographical area 45013.2.2 Data transmission and error rates 45013.2.3 Ownership 45113.2.4 Regulation 45113.2.5 Data routing and topology 45113.2.6 Type of information carried 45213.3 Utilization Benefits 45213.3.1 Peripheral sharing 45313.3.2 Common software access 45313.3.3 Electronic mail 45313.3.4 Gateway access to mainframes 45313.3.5 Internet access 45313.3.6 Virtual private network operations 45413.4 Technological Characteristics 45413.4.1 Topology 45413.4.2 Comparison of topologies 45613.4.3 Signaling methods 45713.4.4 Transmission medium 46013.4.5 Access methods 46013.5 Ethernet Networks 46513.5.1 Original network components 46513.5.2 IEEE 802.3 networks 46813.5.3 Frame composition 49013.5.4 Media access control overview 49513.5.5 Logical link control overview 49513.5.6 Other Ethernet frame types 49813.6 Token-Ring 50413.6.1 Topology 50413.6.2 Redundant versus non-redundant main ring paths 50613.6.3 Cabling and device restrictions 50713.6.4 Constraints 51013.6.5 High speed Token-Ring 51413.6.6 Transmission formats 51513.6.7Medium access control 52413.6.8 Logical link control 52713.7Review Questions 52814 Basic LAN Internetworking 53114.1 Bridge Operations 53114.1.1 Types of bridge 53114.1.2 Network utilization 54414.2 The Switching Hub 54614.2.1 Basic components 54614.2.2 Delay times 54714.2.3 Key advantages of use 54914.2.4 Switching techniques 54914.2.5 Port address support 55314.2.6 Switching architecture 55614.2.7High-speed port operations 55714.2.8 Summary 55814.3 Router Operations 55814.3.1 Basic operation and use of routing tables 55914.3.2 Networking capability 56014.3.3 Communication, transport and routing protocols 56114.3.4 Router classiffications 56314.3.5 Routing protocols 56614.4 Review Questions 57515 Digital Transmission Systems and Equipment 57715.1 The T and E Carriers 57815.1.1 Channel banks 57815.2 T1 Multiplexers 59615.2.1 Waveform-based voice digitization modules 59715.2.2 Vocoding 59815.2.3 Hybrid coding 60115.2.4 T1 multiplexer employment 60215.3 The T3 Carrier 60515.3.1 T3 circuit types 60615.3.2 Evolution 60615.3.3 T3 framing 60915.4 DDS, ASDS and KiloStream facilities 61515.4.1 Applications 61615.4.2 ASDS 61615.4.3 KiloStream service 61715.5 Integrated Services Digital Network (ISDN) 61915.5.1 Concept behind ISDN 61915.5.2 ISDN architecture 62015.5.3 Network characteristics 62115.5.4 ISDN layers 62515.6 Review Questions 62816 Network Architecture 63116.1 SNA Overview 63216.1.1 SNA elements 63416.1.2 System Service Control Point (SSCP) 63416.1.3 Network nodes 63416.1.4 The physical unit 63516.1.5 The logical unit 63516.1.6 SNA network structure 63516.1.7Types of physical unit 63716.1.8 Multiple domains 63716.1.9 SNA layers 63916.1.10 SNA developments 64116.1.11 SNA sessions 64116.2 Advanced Peer-to-Peer Networking (APPN) 64416.2.1 APPC concepts 64416.2.2 APPN architecture 64516.2.3 Operation 64616.3 TCP/IP 64916.3.1 The rise of the Internet 65016.3.2 The TCP/IP protocol suite 65116.3.3 Applications 65316.3.4 TCP/IP communications 66316.3.5 The Internet Protocol (IP) 66416.3.6 Domain Name Service 67916.4 Internetworking 68116.4.1 SNA gateway operations 68216.4.2 Supporting multiple protocols 69016.4.3 Data Link Switching 69316.5 Review Questions 69417 Packet Networks 69717.1 Packet Switching Overview 69817.2 X.25 Networks 70017.2.1 Development period 70017.2.2 Need for PADs 70017.2.3 X.25 layers 70517.2.4 Methods of connection 70817.2.5 Utilization costs 70917.2.6 Tymnet 71117.2.7 Network information 71317.2.8 Features 71317.2.9 Protocol conversion 71517.2.10 LAN interconnectivity 71617.3 Frame Relay 71717.3.1 Comparison to X. 25 71717.3.2 Standards 71917.3.3 Network access 72017.3.4 Frame construction 72117.3.5 Service parameters 72917.3.6 FRAD features 73417.3.7 Voice over Frame Relay 74017.4 Review Questions 74518 Communications Software 74918.1 Terminal Emulation Software Features 74918.1.1 Hardware utilization 75218.1.2 Software utilization 75318.1.3 Operational consideration 75418.1.4 Documentation 75718.1.5 Dialing 75718.1.6 Transmission 76218.1.7Performance efficiency 76618.1.8 Performance flexibility 77018.1.9 Security performance 77218.2 Terminal Emulation Program Examination 77418.2.1 Procomm Plus for Windows 77518.2.2 HyperTerminal 77718.2.3 IBM PC/ 3270 78018.3 Web Browsers 78318.3.1 Microsoft Internet Explorer 78418.3.2 LAN operation 78818.4 Review Questions 78919 Fiber-Optic, Satellite and Wireless Terrestrial Communications 79119.1 Fiber-Optic Transmission Systems 79219.1.1 System components 79219.1.2 Transmission advantages 79919.1.3 Limitations of use 80119.1.4 Utilization economics 80219.1.5 Carrier utilization 80519.1.6 SONET 80619.2 Satellite Communications Systems 81019.2.1 Operation overview 81019.2.2 Satellite access 81019.2.3 Very small aperture terminal (VSAT) 81219.2.4 Low earth orbit satellites 81219.3 Wireless Terrestrial Communications 81419.3.1 Cellular communications 81419.3.2 Wireless LANs 82019.4 Review Questions 82120 Evolving Technologies 82320.1 ATM 82320.1.1 Cell size 82320.1.2 Scalability 82420.1.3 Transparency 82520.1.4 Traffic classiffication 82520.2 The ATM Protocol Stack 82520.2.1 ATM Adaptation Layer 82520.2.2 The ATM Layer 82620.2.3 Physical Layer 82720.3 ATM Operation 82720.3.1 Components 82720.3.2 Network Interfaces 82920.3.3 The ATM cell header 83020.3.4 ATM connections and cell switching 83320.4 Virtual Private Networking 83520.4.1 Rationale for use 83620.4.2 Reliability 83720.4.3 Problem areas 83720.5 Review Questions 838Index 841

"...designed to provide a solid foundation on how data communications systems operate, why, where, and when certain types of equipment should be networked together, and the role of evolving communications technology." (SciTech Book News, Vol. 25, No. 4, December 2001)

Gilbert Held is an internationally recognized author and lecturer who specializes in the applications of computer and communications technology. With over 30 years ofexperience in managing communications networks, he conducts seminars on topics that include LAN/WAN internetworking, data compression, and PC hardware and software. Held has written numerous books on computers and communications technology and has been recognized for his technical excellence in writing.

• Preface xixAcknowledgements xxi1 Communications in a Modern Society 11.1 Applications 11.1.1 Data collection 21.1.2 Transaction processing 31.1.3 Conversational time sharing 51.1.4 Remote job entry 71.1.5 Message switching 71.1.6 Value-added carriers and electronic mail 81.1.7 office automation 121.1.8 Electronic commerce 141.1.9 Satellite transmission 161.2 Constraints 161.2.1 Throughput 171.2.2 Response time 181.2.3 Bandwidth 181.2.4 Economics 191.3 Emerging Trends 191.4 Review Questions 202 Basic Telegraph and Telephone Operations 232.1 Evolution of Communications 232.2 Telegraphy 242.2.1 Operation 242.2.2 Morse code 262.2.3 Morse code limitations 272.2.4 Start-stop signaling and the Baudot code 282.2.5 Bits and codes 292.3 Telephony 322.3.1 Principle of operation 322.3.2 Sound wave conversion 342.3.3 The basic telephone connection 362.3.4 Switchboards and central offices 372.3.5 Numbering plans 392.3.6 Geographic calling areas and network routing 402.3.7The world numbering plan 432.4 Review Questions 433 Basic Circuit Parameters, Measurement Units and Media Overview 473.1 Basic Circuit Parameters 473.1.1 Frequency and bandwidth 473.1.2 The telephone channel passband 493.2 Measurement Units 503.2.1 Power ratios 503.2.2 Signal-to-noise ratio 523.2.3 Reference points 543.3 Media Overview 563.3.1 Twisted-pair cable 563.3.2 Coaxial cable 613.3.3 Microwave 633.3.4 Fiber-optic transmission 643.4 Channel Capacity 673.4.1 Bit versus baud 673.4.2 Nyquist relationship 673.4.3 Shannon's law 683.5 Structured Wiring 693.5.1 The wiring closet 693.5.2 The EIA/TIA-568 standard 693.6 Review Questions 724 Fundamental Data Transmission Concepts 754.1 Analog Line Connections 754.1.1 The analog switched line 764.1.2 Analog leased line 794.1.3 Dedicated line 824.1.4 Switched network vs leased line economics 834.2 Types of Service and Transmission Devices 844.2.1 Digital repeaters 854.2.2 Modems 864.2.3 Acoustic couplers 874.2.4 Analog facilities 894.2.5 Digital facilities 934.2.6 Digital signaling 934.2.7Representative AT&T digital offerings 964.3 Transmission Mode 984.3.1 Simplex transmission 984.3.2 Half-duplex transmission 994.3.3 Full-duplex transmission 1004.3.4 Terminal and mainframe computer operating modes 1014.4 Transmission Techniques 1034.4.1 Asynchronous transmission 1034.4.2 Synchronous transmission 1054.5 Types of Transmission 1064.6 Wide Area Network Transmission Structures 1074.6.1 Mainframe computer-based network structure 1084.6.2 LAN network structure 1094.6.3 LAN internetworking structure 1104.7Line Discipline 1114.8 Transmission Rate 1134.8.1 Analog service 1134.8.2 Digital service 1144.9 Transmission Codes 1154.9.1 Morse code 1154.9.2 Baudot code 1164.9.3 BCD code 1164.9.4 Extended binary-coded decimal interchange code (EBCDIC) 1164.9.5 ASCII code 1184.10 Review Questions 1225 Terminals, Workstations and WAN and LAN Networking Overview 1255.1 Terminals 1265.1.1 Interactive terminal classi®cation 1265.1.2 Terminal evolution 1275.2 Workstations and Other LAN Components 1415.2.1 Network interface card 1415.2.2 Hubs 1425.2.3 File server 1435.2.4 Print server 1455.2.5 Other types of servers 1465.3 Wide Area Networking Overview 1465.3.1 Multiplexing and data concentration 1465.3.2 Front-end processor 1515.3.3 Network configurations 1515.4 Local Area Networking Overview 1525.4.1 Repeaters 1535.4.2 Bridges 1535.4.3 Routers 1545.4.4 Gateways 1555.5 Review Questions 1576 Representative Standards Organizations: the OSI Reference Model 1596.1 National Standards Organizations 1606.1.1 American National Standards Institute (ANSI) 1606.1.2 Electronic Industries Association (EIA) 1616.1.3 Federal Information Processing Standards (FIPS) 1636.1.4 Institute of Electrical and Electronic Engineers (IEEE) 1636.1.5 British Standards Institution (BSI) 1646.1.6 Canadian Standards Association (CSA) 1646.2 International Standards Organizations 1646.2.1 International Telecommunications Union (ITU) 1646.2.2 International Standards Organization (ISO) 1656.3 De facto Standards 1676.3.1 AT&T compatibility 1686.3.2 Cross-licensed technology 1696.3.3 Bellcore/Telcordia Technology 1696.3.4 Internet standards 1706.4 The OSI Reference Model 1716.4.1 Layered architecture 1726.4.2 OSI layers 1736.4.3 Data flow 1766.5 IEEE 802 Standards 1776.5.1 802 committees 1776.5.2 Data link subdivision 1796.6 Review Questions 1807 The Physical Layer, Cables, Connectors, Plugs and Jacks 1837.1 DTE/DCE Interfaces 1847.1.1 Connector overview 1867.1.2 RS-232-C/D 1887.1.3 Differential signaling 1987.1.4 RS- 449 2007.1.5 V. 35 2027.1.6 RS-366-A  2037.1.7 X.21 and X. 20 2047.1.8 X.21 bis 2077.1.9 RS- 530 2077.1.10 High Speed Serial Interface 2987.1.11 High Performance Parallel Interface 2147.1.12 Universal Serial Bus 2167.1.13 IEEE 1394 (FireWire) 2187.2 Cables and Connectors 2227.2.1 Twisted-pair cable 2227.2.2 Low-capacitance shielded cable 2237.2.3 Ribbon cable 2237.2.4 The RS-232 null modem 2237.2.5 RS-232 cabling tricks 2257.3 Plugs and Jacks 2267.3.1 Connecting arrangements 2287.3.2 Telephone options 2307.3.3 Ordering the business line 2317.3.4 LAN connectivity 2327.4 Review Questions 2338 Basic Transmission Devices: Line Drivers, Modems, and Service Units 2358.1 Line Drivers 2368.1.1 Direct connection 2368.1.2 Using line drivers 2398.2 Modem Operations 2438.2.1 The modulation process 2438.2.2 Bps vs. baud 2468.2.3 Voice circuit parameters 2468.2.4 Combined modulation techniques 2478.2.5 Mode of transmission 2538.2.6 Transmission techniques 2548.2.7 Modem classiffication 2558.2.8 Limited-distance modems 2568.2.9 Line-type operations 2578.2.10 Reverse and secondary channels 2578.2.11 Equalization 2588.2.12 Synchronization 2608.2.13 Multiport capability 2608.2.14 Security capability 2618.2.15 Multiple speed selection capability 2618.2.16 Voice/data capability 2628.2.17Modem handshaking 2628.2.18 Self-testing features 2638.2.19 Modem indicators 2658.2.20 Modern operations and compatibility 2658.3 Intelligent Modems 2898.3.1 Hayes command set modems 2898.3.2 Key intelligent modem features 2968.3.3 Microcom Networking Protocol (MNP) 3028.3.4 Data compression 3068.3.5 MNP Class 5 compression 3068.3.6 MNP Class 7enhanced data compression 3088.3.7V.42bis 3118.4 Broadband Modems 3128.4.1 Telephone and cable TV infrastructure 3138.4.2 Cable modems 3178.4.3 DSL modems 3248.5 Service Units 3308.5.1 The DSU 3318.5.2 The CSU 3318.6 Review Questions 3329 Regulators and Carriers 3359.1 Regulators 3369.1.1 US regulatory evolution 3369.1.2 International regulatory authorities 3429.2 Carrier Offerings 3439.2.1 AT&T system evolution 3439.2.2 The Bell system 3459.2.3 The regional Bell operating companies 3469.2.4 AT&T service offerings 3499.2.5 Regional Bell operating company offerings 3559.3 ATM Overview 3569.4 Review Questions 35710 Transmission Errors: Causes, Measurements and Correction Methods 35910.1 Causes of Transmission Errors 35910.2 Performance Measurements 36010.2.1 Bit error rate 36010.2.2 Bit error rate tester 36010.2.3 BERT time 36210.2.4 Performance classiffications 36210.2.5 Block error rate testing 36410.2.6 Error-free second testing 36510.3 Error Detection and Correction Techniques 36510.3.1 Asynchronous transmission 36510.3.2 Synchronous transmission 37010.4 Review Questions 37411 The WAN Data Link Layer 37711.1 Terminal and Data Link Protocols: Characteristics and Functions 37811.1.1 Transmission sequence 37911.1.2 Error control 37911.2 Types of Protocol 38011.2.1 Teletypewriter protocols 38011.2.2 PC file transfer protocols 38511.2.3 Bisynchronous protocols 39511.2.4. Digital Data Communications Message Protocol (DDCMP) 40011.2.5 Bit-oriented line control procedures 40211.3 Review Questions 40712 Increasing WAN Line Utilization 40912.1 Multiplexers 41012.1.1 Evolution 41012.1.2 Device support 41012.1.3 Multiplexing techniques 41112.2 Control Units 43912.2.1 Control unit concept 44012.2.2 Attachment methods 44012.2.3 Unit operation 44212.2.4 Breaking the closed system 44312.3 Review Questions 44513 Local Area Networks 44913.1 Origin 44913.2 Comparison with WANs 45013.2.1 Geographical area 45013.2.2 Data transmission and error rates 45013.2.3 Ownership 45113.2.4 Regulation 45113.2.5 Data routing and topology 45113.2.6 Type of information carried 45213.3 Utilization Benefits 45213.3.1 Peripheral sharing 45313.3.2 Common software access 45313.3.3 Electronic mail 45313.3.4 Gateway access to mainframes 45313.3.5 Internet access 45313.3.6 Virtual private network operations 45413.4 Technological Characteristics 45413.4.1 Topology 45413.4.2 Comparison of topologies 45613.4.3 Signaling methods 45713.4.4 Transmission medium 46013.4.5 Access methods 46013.5 Ethernet Networks 46513.5.1 Original network components 46513.5.2 IEEE 802.3 networks 46813.5.3 Frame composition 49013.5.4 Media access control overview 49513.5.5 Logical link control overview 49513.5.6 Other Ethernet frame types 49813.6 Token-Ring 50413.6.1 Topology 50413.6.2 Redundant versus non-redundant main ring paths 50613.6.3 Cabling and device restrictions 50713.6.4 Constraints 51013.6.5 High speed Token-Ring 51413.6.6 Transmission formats 51513.6.7Medium access control 52413.6.8 Logical link control 52713.7Review Questions 52814 Basic LAN Internetworking 53114.1 Bridge Operations 53114.1.1 Types of bridge 53114.1.2 Network utilization 54414.2 The Switching Hub 54614.2.1 Basic components 54614.2.2 Delay times 54714.2.3 Key advantages of use 54914.2.4 Switching techniques 54914.2.5 Port address support 55314.2.6 Switching architecture 55614.2.7High-speed port operations 55714.2.8 Summary 55814.3 Router Operations 55814.3.1 Basic operation and use of routing tables 55914.3.2 Networking capability 56014.3.3 Communication, transport and routing protocols 56114.3.4 Router classiffications 56314.3.5 Routing protocols 56614.4 Review Questions 57515 Digital Transmission Systems and Equipment 57715.1 The T and E Carriers 57815.1.1 Channel banks 57815.2 T1 Multiplexers 59615.2.1 Waveform-based voice digitization modules 59715.2.2 Vocoding 59815.2.3 Hybrid coding 60115.2.4 T1 multiplexer employment 60215.3 The T3 Carrier 60515.3.1 T3 circuit types 60615.3.2 Evolution 60615.3.3 T3 framing 60915.4 DDS, ASDS and KiloStream facilities 61515.4.1 Applications 61615.4.2 ASDS 61615.4.3 KiloStream service 61715.5 Integrated Services Digital Network (ISDN) 61915.5.1 Concept behind ISDN 61915.5.2 ISDN architecture 62015.5.3 Network characteristics 62115.5.4 ISDN layers 62515.6 Review Questions 62816 Network Architecture 63116.1 SNA Overview 63216.1.1 SNA elements 63416.1.2 System Service Control Point (SSCP) 63416.1.3 Network nodes 63416.1.4 The physical unit 63516.1.5 The logical unit 63516.1.6 SNA network structure 63516.1.7Types of physical unit 63716.1.8 Multiple domains 63716.1.9 SNA layers 63916.1.10 SNA developments 64116.1.11 SNA sessions 64116.2 Advanced Peer-to-Peer Networking (APPN) 64416.2.1 APPC concepts 64416.2.2 APPN architecture 64516.2.3 Operation 64616.3 TCP/IP 64916.3.1 The rise of the Internet 65016.3.2 The TCP/IP protocol suite 65116.3.3 Applications 65316.3.4 TCP/IP communications 66316.3.5 The Internet Protocol (IP) 66416.3.6 Domain Name Service 67916.4 Internetworking 68116.4.1 SNA gateway operations 68216.4.2 Supporting multiple protocols 69016.4.3 Data Link Switching 69316.5 Review Questions 69417 Packet Networks 69717.1 Packet Switching Overview 69817.2 X.25 Networks 70017.2.1 Development period 70017.2.2 Need for PADs 70017.2.3 X.25 layers 70517.2.4 Methods of connection 70817.2.5 Utilization costs 70917.2.6 Tymnet 71117.2.7 Network information 71317.2.8 Features 71317.2.9 Protocol conversion 71517.2.10 LAN interconnectivity 71617.3 Frame Relay 71717.3.1 Comparison to X. 25 71717.3.2 Standards 71917.3.3 Network access 72017.3.4 Frame construction 72117.3.5 Service parameters 72917.3.6 FRAD features 73417.3.7 Voice over Frame Relay 74017.4 Review Questions 74518 Communications Software 74918.1 Terminal Emulation Software Features 74918.1.1 Hardware utilization 75218.1.2 Software utilization 75318.1.3 Operational consideration 75418.1.4 Documentation 75718.1.5 Dialing 75718.1.6 Transmission 76218.1.7Performance efficiency 76618.1.8 Performance flexibility 77018.1.9 Security performance 77218.2 Terminal Emulation Program Examination 77418.2.1 Procomm Plus for Windows 77518.2.2 HyperTerminal 77718.2.3 IBM PC/ 3270 78018.3 Web Browsers 78318.3.1 Microsoft Internet Explorer 78418.3.2 LAN operation 78818.4 Review Questions 78919 Fiber-Optic, Satellite and Wireless Terrestrial Communications 79119.1 Fiber-Optic Transmission Systems 79219.1.1 System components 79219.1.2 Transmission advantages 79919.1.3 Limitations of use 80119.1.4 Utilization economics 80219.1.5 Carrier utilization 80519.1.6 SONET 80619.2 Satellite Communications Systems 81019.2.1 Operation overview 81019.2.2 Satellite access 81019.2.3 Very small aperture terminal (VSAT) 81219.2.4 Low earth orbit satellites 81219.3 Wireless Terrestrial Communications 81419.3.1 Cellular communications 81419.3.2 Wireless LANs 82019.4 Review Questions 82120 Evolving Technologies 82320.1 ATM 82320.1.1 Cell size 82320.1.2 Scalability 82420.1.3 Transparency 82520.1.4 Traffic classiffication 82520.2 The ATM Protocol Stack 82520.2.1 ATM Adaptation Layer 82520.2.2 The ATM Layer 82620.2.3 Physical Layer 82720.3 ATM Operation 82720.3.1 Components 82720.3.2 Network Interfaces 82920.3.3 The ATM cell header 83020.3.4 ATM connections and cell switching 83320.4 Virtual Private Networking 83520.4.1 Rationale for use 83620.4.2 Reliability 83720.4.3 Problem areas 83720.5 Review Questions 838Index 841

"...designed to provide a solid foundation on how data communications systems operate, why, where, and when certain types of equipment should be networked together, and the role of evolving communications technology." (SciTech Book News, Vol. 25, No. 4, December 2001)