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Table of Contents |
9 |
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Preface |
15 |
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1. Computer Communications Networks - Introduction |
18 |
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1.1. Main Components |
19 |
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1.1.1. The Computer System |
19 |
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1.1.2. The Communications System |
20 |
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1.1.3. The Networking System |
21 |
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1.1.3.1. Communication Systems Versus Networking Systems |
21 |
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1.2. Network Development Example |
22 |
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1.2.1. Three Role Players |
22 |
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1.2.2. Network Design |
23 |
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1.2.2.1. User/IT Staff |
25 |
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1.2.2.2. Network Provider |
25 |
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1.2.2.3. Network Designer/Vendor |
25 |
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1.2.2.4. Relevance of the text to the above role players |
25 |
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1.3. Standardization |
26 |
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1.3.1. Example 1 - Communication of Voice |
26 |
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1.3.2. Example 2 - File Transfer |
27 |
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1.3.2.1. Circuit Switching |
28 |
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1.3.2.2. Packet Switching |
29 |
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1.4. Classification of Networks There are several ways of |
29 |
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1.4.1. Local Area Networks (LANs) |
29 |
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1.4.2. Wide Area Networks (WANs) |
29 |
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1.4.3. Metropolitan Area Networks (MANs) |
30 |
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1.5. Network Protocol Architecture |
30 |
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1.5.1. Protocols |
30 |
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1.5.2. Standards |
30 |
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1.5.3. Protocol Architecture |
31 |
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1.5.3.1. A Protocol Layer |
31 |
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1.6. Example of a Protocol Architecture |
31 |
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1.6.1. Open System |
32 |
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1.7. Summary |
32 |
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1.8. Review Questions |
33 |
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2. Network Architectures - Examples |
34 |
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2.1. The OSI Reference Model (OSI-RM) |
35 |
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2.1.1. OSI-RM Characteristics and Terminology |
35 |
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2.1.2. Communications Model within an OSI Node |
36 |
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2.1.3. Communications Across the OSI Network |
39 |
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2.1.4. Inter-layer communication |
40 |
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2.1.4.1. The Role of the Lower Layers |
41 |
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2.1.5. OSI-RM Layer Definitions and Functions |
42 |
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2.1.5.1. The Physical Layer |
42 |
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2.1.5.2. The Data Link Control Layer (DLC) |
43 |
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2.1.5.3. The Network Layer (NET) |
44 |
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2.1.5.3.1. Datagram or Connectionless Switching |
45 |
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2.1.5.3.2. Virtual Circuit (VC) Switching |
45 |
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2.1.5.3.3. Circuit Switching (CS) |
46 |
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2.1.5.3.4. A Comparison of Switching Schemes |
47 |
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2.1.5.3.5. Quality of Service (QoS) |
47 |
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2.1.5.4. The Transport Layer (TL) |
51 |
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2.1.5.5. The Session Layer |
51 |
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2.1.5.6. The Presentation Layer |
51 |
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2.1.5.7. The Application Layer |
52 |
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2.2. The TCP/IP Protocol Suite |
53 |
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2.2.1. The Internet Protocol (IP) |
56 |
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2.2.2. The Transmission Control Protocol (TCP) |
57 |
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2.2.3. The Application Protocols for the Internet |
58 |
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2.2.4. Lower Layers of the Internet |
58 |
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2.3. The IEEE Wireless Local Area Network (IEEE WLAN) |
59 |
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2.3.1. Local Area Networks |
59 |
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2.3.2. Wireless Local Area Networks |
60 |
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2.3.3. The Physical Layer (PHY) |
62 |
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2.3.3.1. Spread Spectrum Communications |
63 |
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2.3.4. The Medium Access Control (MAC) Layer |
63 |
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2.3.4.1. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) |
64 |
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2.4. Framework for Studying a Protocol |
64 |
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2.5. Standardization of Protocols |
65 |
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2.5.1. International Telecommunications Union (ITU) |
66 |
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2.5.2. The Internet Society |
66 |
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2.5.2.1. Internet Architecture Board (IAB) |
66 |
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2.5.2.2. Internet Engineering Steering Group (IESG) |
67 |
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2.5.2.3. Internet Engineering Task Force (IETF) |
67 |
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2.5.3. International Organization for Standardization (ISO) |
67 |
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2.5.4. European Telecommunications Standards Institute (ETSI) |
67 |
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2.5.5. American National Standard Institute (ANSI) |
67 |
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2.5.6. Institute of Electrical and Electronic Engineers (IEEE) |
68 |
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2.6. Summary |
69 |
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2.7. Review Questions |
70 |
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3. Network and User Data |
72 |
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3.1. The Network Data |
73 |
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3.2. The Physical Layer Data |
74 |
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3.2.1. Sequence of Events and Definitions |
74 |
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3.2.2. Modulation of data and signals |
84 |
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3.2.2.1. Baseband and Passband Modulations |
85 |
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3.2.3. Digital Encoding of Data |
87 |
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3.2.4. Non-Return to Zero (NRZ) |
88 |
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3.2.5. Multilevel Encoding |
89 |
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3.2.5.1. Bipolar-AMI (Alternative Mark-Inversion) Coding |
90 |
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3.2.5.2. Multi-level 3 (MLT-3) Coding |
90 |
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3.2.6. Manchester Coding |
90 |
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3.2.7. General Characteristics of Bit Encoding |
91 |
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3.2.8. Zero-substitution and nB/NB Translation |
92 |
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3.3. Passband Modulation |
93 |
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3.3.1. The Carrier Signal |
93 |
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3.3.2. Analog Modulation |
94 |
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3.3.2.1. Amplitude Modulation (AM) |
95 |
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3.3.2.2. Angle Modulation |
96 |
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3.4. Digital Modulation |
97 |
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3.4.1. Amplitude Shift Keying (ASK) |
97 |
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3.4.2. Frequency Shift Keying (FSK) |
98 |
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3.4.3. Phase Shift Keying (PSK) |
99 |
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3.4.3.1. Quadrature Phase Shift Keying (QPSK) |
99 |
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3.4.3.2. Signal Constellation |
100 |
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3.5. The User Data |
101 |
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3.5.1. Digital Transmission of Voice |
101 |
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3.5.2. The Sampling Theorem |
102 |
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3.5.3. Pulse Coded Modulation (PCM) |
102 |
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3.5.4. Delta Modulation |
108 |
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3.6. Text and Numerical Data |
110 |
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3.6.1. ASCII (American National Standard Code for Information Interchange) |
111 |
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3.6.1.1. ASCII and Other Standard Organizations |
112 |
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3.6.2. ISO 8859-1 (ISO Latin -1) |
112 |
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3.6.3. UCS (Universal multiple-octet coded Character Set) |
113 |
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3.7. Summary |
115 |
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3.8. Review Questions |
116 |
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4. The Physical Layer |
118 |
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4.1. Channel Impairments |
119 |
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4.1.1. Signal Attenuation |
119 |
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4.1.1.1. Attenuation and Propagation Loss |
119 |
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4.1.2. Delay Distortion |
121 |
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4.1.3. Noise |
122 |
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4.1.3.1. Thermal Noise |
123 |
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4.1.3.2. Crosstalk |
123 |
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4.1.3.3. Impulse Noise |
123 |
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4.1.4. Multipath |
123 |
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4.2. Transmission Media |
124 |
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4.3. Cables in data communications |
125 |
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4.3.1. Twisted Pair Copper Cables |
125 |
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4.3.2. Co-axial Cable |
127 |
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4.3.3. Optical Fiber Cable (OFC) |
128 |
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4.4. The Wireless Media |
128 |
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4.4.1. Characteristics |
129 |
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4.4.2. Examples of Wireless Bands |
129 |
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4.5. Physical Layer Protocol Example: EIA-232-F |
130 |
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4.5.1. Mechanical Characteristics |
131 |
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4.5.2. Electrical Characteristics |
133 |
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4.5.3. Functional Characteristics |
133 |
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4.5.4. Procedural Characteristics |
135 |
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4.5.4.1. Call setup for full-duplex connection |
135 |
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4.5.4.2. Call setup for half-duplex connection |
136 |
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4.5.4.3. Loopback Testing |
136 |
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4.5.4.4. The NULL Modem |
137 |
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4.5.5. PHY for IEEE Wireless Local Area Network |
138 |
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4.5.6. WLAN Types |
139 |
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4.5.7. Frequency Hopping Spread Spectrum (FH-SS) for 2.4 GHz Specification |
140 |
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4.5.7.1. PLCP for frequency hopping |
141 |
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4.5.7.2. The PMD for Frequency Hopping Spread Spectrum |
142 |
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4.5.8. Direct Sequence Spread Spectrum (DS-SS) for 2.4 GHz Specification |
143 |
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4.5.9. Infrared PHY for IEEE WLAN |
144 |
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4.6. The Integrated Services Digital Network (ISDN) PHY |
145 |
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4.7. Review Questions |
147 |
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5. Data Link Control Layer Functions and Procedures |
148 |
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5.1. Data Link Layer Functions |
149 |
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5.1.1. Synchronization |
149 |
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5.1.2. Addressing Modes |
149 |
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5.1.3. Connection setup and termination |
150 |
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5.1.4. Error Control |
150 |
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5.1.5. Flow Control |
150 |
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5.1.6. Link Control and Testing |
150 |
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5.1.7. Multiplexing |
151 |
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5.2. Synchronization |
151 |
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5.2.1. Synchronous Transmission |
151 |
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5.2.1.1. Bit Stuffing |
152 |
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5.2.2. Asynchronous Transmission |
153 |
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5.3. Connection Setup and Termination |
156 |
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5.4. Addressing |
157 |
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5.5. Error Control |
159 |
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5.5.1. Parity bit |
161 |
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5.5.2. Block Error Check |
163 |
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5.5.3. The Cyclic Redundancy Check (CRC) |
163 |
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5.5.3.1. Parity block generation |
164 |
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5.5.3.2. Error Detection Procedure |
165 |
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5.5.3.3. Polynomial representation of binary numbers |
168 |
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5.5.3.4. Implementation of CRC |
170 |
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5.5.3.5. How to Decide C(X) |
172 |
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5.5.3.6. Error Detection Power of CRC |
172 |
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5.5.3.7. Error Recovery Mechanisms |
173 |
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5.6. Flow Control |
173 |
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5.6.1. Stop-and-Wait (SnW) Flow Control |
173 |
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5.6.2. The Sliding-windows (SW) Flow Control Mechanism |
175 |
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5.6.3. Link Utilization of Window Flow Control Mechanisms |
179 |
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5.6.4. Full-duplex Communications Using Window Flow Control |
180 |
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5.7. Flow Control Based Error Recovery Mechanisms |
181 |
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5.7.1. Stop-and-Wait ARQ |
181 |
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5.7.2. Go-Back-N ARQ |
182 |
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5.7.2.1. Full-duplex operation |
182 |
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5.7.2.2. Piggybacking |
182 |
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5.7.3. Selective Reject ARQ |
183 |
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5.7.4. Maximum Window Size |
184 |
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5.8. Link Control and Testing |
185 |
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5.9. Review Questions |
186 |
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6. Data Link Control Layer Protocol Examples |
188 |
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6.1. HDLC (High-level Data Link Control) Protocol |
189 |
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6.2. HDLC Frame Types |
189 |
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6.3. HDLC station types |
193 |
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6.3.1. Primary station |
193 |
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6.3.2. Secondary station |
193 |
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6.3.3. Combined stations |
193 |
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6.4. Operation modes |
193 |
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6.4.1. Normal Response Mode (NRM) |
193 |
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6.4.2. Asynchronous Balanced Mode (ABM) |
193 |
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6.4.3. Asynchronous Response Mode (ARM) |
194 |
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6.4.4. Extended Modes |
194 |
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6.5. The HDLC Frame |
194 |
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6.5.1. Flag |
194 |
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6.5.2. Address Field |
194 |
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6.5.2.1. Extended address format |
195 |
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6.5.3. Frame Check Sequence (FCS) |
195 |
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6.6. HDLC Protocol Operation |
195 |
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6.6.1. Selection of Timeout |
196 |
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6.6.2. Connection Setup and Termination |
196 |
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6.6.3. Data Exchange |
197 |
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6.6.3.1. Half-duplex Connection |
198 |
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6.6.3.2. Use of RR and RNR for Busy Condition Notice and Recovery |
201 |
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6.6.3.3. Use of REJ and SREJ |
201 |
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6.7. Asynchronous Transfer Mode (ATM) Protocol |
202 |
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6.7.1. The ATM Cell |
203 |
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6.7.1.1. Generic Flow Control (GFC) |
203 |
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6.7.1.2. Virtual Path/Channel Identifiers (VPI/VCI) |
204 |
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6.7.1.3. Control Bits |
206 |
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6.7.1.4. Header Error Control (HEC) |
207 |
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6.8. ATM Protocol Procedures |
208 |
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6.8.1. Virtual circuit and the frame relay protocol |
208 |
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6.8.2. Error Control |
209 |
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6.9. Medium Access Control (MAC) Layer for IEEE Wireless LANs |
210 |
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6.9.1. Random Access in LANs |
211 |
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6.9.2. Collision Avoidance |
212 |
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6.9.3. The Distributed Coordination Function (DCF) |
213 |
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6.9.3.1. Interframe Spacing (IFS) |
214 |
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6.9.4. MAC Frame Structure |
214 |
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6.9.5. MAC Frame Types |
215 |
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6.10. Review Questions |
217 |
|
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7. Multiplexing and Carrier Systems |
218 |
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7.1. Analog and Digital Transmissions |
219 |
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7.1.1. Analog and Digital Multiplexing |
219 |
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7.1.2. Frequency Division Multiplexing (FDM) |
220 |
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7.1.3. Frequency Division Duplexing (FDD) |
221 |
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7.1.4. Time Division Multiplexing (TDM) |
222 |
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7.1.5. Synchronous TDM |
222 |
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7.1.6. Statistical TDM |
223 |
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7.1.7. Statistical Versus Synchronous TDM |
225 |
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7.1.8. The TDM Switch |
226 |
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7.1.8.1. Framing |
227 |
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7.1.8.2. Pulse stuffing |
228 |
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7.2. Digital Carrier Systems |
228 |
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7.3. The DS-1 Carrier System |
229 |
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7.3.1. Total Bit Rate |
230 |
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7.3.2. Signaling Information |
230 |
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7.3.3. Problems with T-1/E-1 Systems |
231 |
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7.4. Synchronous Optical Network/ Synchronous Digital Hierarchy |
232 |
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7.5. Digital Subscriber’s Line (DSL) |
234 |
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7.5.1.8.1. Integration With Telephone |
235 |
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7.6. Multiplexing at higher layers |
235 |
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7.6.1. Multiple Protocols Per Layer With Connection-oriented Mode |
236 |
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7.6.2. Multiple Connections Per Protocol |
237 |
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7.7. Review Questions |
239 |
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8. The Network and Higher Layer Functions |
240 |
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8.1. The Network Layer |
241 |
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8.2. Typical Functions of Network layer |
242 |
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8.2.1. Connectionless Network Layers |
242 |
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8.2.2. Connection-oriented Mode |
246 |
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8.3. The End-to-end Layers |
247 |
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8.4. X.25 Packet Layer Protocol |
249 |
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8.4.1. X.25 Packet Types |
250 |
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8.5. Review Questions |
253 |
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9. Performance Models for Data Networks |
254 |
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9.1. The Network Performance |
255 |
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9.2. Performance of the Physical Layer Protocols |
256 |
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9.2.1. Performance Improvement at PHY |
257 |
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9.2.1.1. Channel Errors |
257 |
|
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9.2.1.2. Receiver Accuracy |
258 |
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9.3. Data Link Layer Performance |
259 |
|
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9.3.1. Flow Control Procedures |
260 |
|
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9.3.2. Error Control Procedures |
263 |
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9.3.2.1. Performance Models for FEC and BEC |
263 |
|
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9.4. Performance of the MAC Sublayer |
265 |
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9.5. Performance of the network and higher layers |
266 |
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9.5.1. Connectionless and Connection-oriented Protocols |
267 |
|
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9.5.2. QoS Differentiation in Connectionless Protocols |
269 |
|
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9.5.2.1. Priority Queueing |
269 |
|
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9.5.2.2. Fair Queueing |
270 |
|
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9.5.2.3. Custom Queueing |
270 |
|
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9.5.3. Performance of End-to-end Protocols |
271 |
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9.6. System Simulation for Performance Prediction |
272 |
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9.6.1. What is Simulation? |
272 |
|
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9.6.1.1. What is a Random Number? |
273 |
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9.6.1.2. The Uniform Random Variable |
273 |
|
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9.6.1.3. What is a Pseudorandom Number? |
274 |
|
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9.6.2. Designing a Simulation Program Versus Using a Package |
274 |
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9.7. Performance of Wireless and Mobile Networks |
274 |
|
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9.7.1. The Wireless Network Channel |
275 |
|
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9.7.1.1. Propagation Loss |
275 |
|
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9.7.1.2. Interference |
275 |
|
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9.7.1.3. Frequency Selectiveness |
276 |
|
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9.7.1.4. Time Selectiveness |
277 |
|
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9.7.1.5. Multipath |
278 |
|
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9.7.1.6. Diversity |
278 |
|
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9.7.2. Resource Management in Wireless Networks |
279 |
|
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9.7.3. Mobility Management in Mobile Networks |
281 |
|
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9.7.3.1. Handoff |
282 |
|
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9.7.3.2. Registration |
282 |
|
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9.8. Review Questions |
283 |
|
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References |
284 |
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Index |
290 |
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More eBooks at www.ciando.com |
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