Basics of computer networks

A handbook containing basic issues related to the organization and use of the global network (Internet), with particular emphasis on data transmission protocols. The following sections describe the individual layers of protocols, from the lowest (physical layer) to the highest (application layer). Explained the purposefulness of individual layers, implementation and achievable parameters. The last chapter is devoted to the problems of data security, which plays an increasingly important role in this field.
After each chapter there is a set of exercises recommended for self-solution. The approach is clear and precise. Concepts, principles of operation and descriptions of solutions are introduced in a systematic manner.
Knowledge is passed in an orderly way.
Recipients of the book: first-cycle students in the field of Computer Science and related faculties, students of electronic and IT technicians, as well as engineers dealing with computer networks.

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Table of Contents:
Foreword 10
1. Introduction 13
1.1. What is this book about? 13
1.2. Other sources of information 16
1.3. How big is a megabyte? 17
1.4. History of the Internet 18
1.5. Internet management 22
1.6. Exercises 24
2. Layered network model 25
2.1. Introduction 25
2.2. Seven-layer network model 26
2.2.1. Physical layer 26
2.2.2. Data link layer 27
2.2.3. Network layer 27
2.2.4. Transport layer 27
2.2.5. Session layer 29
2.2.6. Presentation layer 29
2.2.7. Application layer 29
2.3. How do layers interact with each other? 29
2.4. What are the layers and encapsulation for? thirty
2.5. Internet model 32
2.5.1. Link layer 33
2.5.2. Network layer 33
2.5.3. Transport layer 33
2.5.4. Application layer 34
2.6. Models and protocols 35
2.7. Comparison of OSI and Internet models 35
2.8. Exercises 36
3. Physical layer and link layer 1: Ethernet 38
3.1. Introduction 38
3.2. Ethernet 38
3.3. CSMA / CD transmission 40
3.4. Ethernet equipment 41
3.4.1. Farther and faster 45
3.5. Physical coding 48
3.6. Alternatives to Ethernet 51
3.7. Exercises 53
4. Physical layer and link layer 2: further 54
4.1. Introduction 54
4.2. Modems 54
4.3. Digital system with integration of ISDN services 58
4.4. SLIP and PPP protocols 61
4.4.1. SLIP 61 protocol
4.4.2. PPP protocol 63
4.5. T and E hierarchy and SONET / SDH network. 64
4.5.1. T and E 64 frames
4.5.2. Optical network SONET / SDH 65
4.6. ATM 66 protocol
4.7. MPLS 68 technology
4.8. Asymmetrical digital access ADSL 70
4.9. Exercises 75
5. Physical layer and link layer 3: wireless networks 76
5.1. Introduction 76
5.2. Wireless Ethernet 77
5.2.1. Standard 802.11. 78
5.2.2. Spectrum scattering 78
5.2.3. 802.11a and 802.11g 84 standards
5.2.4. Wireless networks 86
5.2.5. Other wireless networks 90
5.3. Last mile problem 96
5.4. ARP 98 protocol
5.4.1. Bridge connections 100
5.4.2. Inverse ARP 102
5.5. Exercises 103
6. Internet layer / network layer: IP protocol 104
6.1. Introduction 104
6.2. IP headings 105
6.2.1. Version 105
6.2.2. Length of the header 106
6.2.3. Service type 106
6.2.4. Overall length 107
6.2.5. Identification 108
6.2.6. Tag bits 108
6.2.7. Shift of fragment 109
6.2.8. Life time 110
6.2.9. Protocol 111
6.2.10. Checksum header 111
6.2.11. Source address and destination address 112
6.2.12. Optional fields 112
6.3. IP addresses and routing tables 113
6.4. Networks and IP addresses 115
6.5. Subnetting 117
6.6. Classless networks 118
6.6.1. Classless Routing CIDR 119
6.7. Network address translation, NAT 120
6.8. IPv6 protocol 121
6.9. Single, group and wildcard addresses 125
6.9.1. Annunciation 126
6.9.2. Group sending 127
6.9.3. Addressing one of many 130
6.10. Dynamic Host Configuration Protocol, DHCP 132
6.11. Mobile IP 136
6.12. Internet protocol of ICMP 139 control messages
6.12.1. Ping 141
6.12.2. Traceroute command 143
6.13. Exercises 145
7. Selecting the IP protocol route 148
7.1. Introduction 148
7.2. ICMP message redirect 149
7.3. Dynamic routing protocol 150
7.3.1. Distance vector and link state protocols 150
7.3.2. RIP 151 protocol
7.3.3. Dijkstra's algorithm 154
7.3.4. Protocol of the shortest path of OSPF 156
7.3.5. BGP protocol 157
7.4. Exercises 158
8. Domain name system 159
8.1. Introduction 159
8.2. Hierarchy 159
8.3. Recursive search 162
8.4. Reverse search 166
8.5. Other data 167
8.6. Format of the 169 package
8.6.1. Inquiries 170
8.6.2. Answers 171
8.7. Other information 171
8.8. Exercises 174
9. Transport layer 175
9.1. Introduction 175
9.2. Ports 175
9.3. Transport layer: UDP protocol 177
9.3.1. UDP packet header 177
9.3.2. Comments, comments 178
9.4. Transport layer: TCP protocol 179
9.4.1. Ports 180
9.4.2. Sequential numbers and confirmation numbers 180
9.4.3. The length of the heading 182
9.4.4. Bits of tags 182
9.4.5. Window size 182
9.4.6. Checksum 183
9.4.7. Urgent data indicator 183
9.4.8. Options 183
9.4.9. Data 184
9.4.10. Connection protocol 184
9.4.11. Connection completion report 185
9.4.12. Reset 186
9.4.13. TPC 187 state machine
4.9.14. TPC 189 options
9.5. Exercises 190
10. TCP strategies 191
10.1. Introduction 191
10.2. Sliding window 191
10.3. Delayed confirmation 192
10.4. Nagle's algorithm 194
10.5. The stupid window syndrome 195
10.6. Prevention of overloads 196
10.6.1. Free start and prevention of blockages 197
10.6.2. Fast retransmission and quick data recovery 199
10.6.3. Notification of congestion 199
10.7. Retransmission timer 200
10.8. Hold timer 202
10.9. Presence timer 203
10.10. Discovering the MTU of path 204
10.11. Fat Pipe connections 205
10.12. Timestamps 207
10.13. Selective confirmation of SACK 207
10.14. Theoretical throughput 209
10.15. Alternatives to TCP 209
10.15.1. Transactional TCP 209
10.15.2. Stream control protocol 210
10.16. Exercises 215
11. Presentation layer 217
11.1. Introduction 217
11.2. Character encoding 217
11.3. Other data: XDR 219
11.4. MIME protocol 222
11.5. Line end marker 223
11.6. Exercises 224
12. Application layer 225
12.1. Introduction 225
12.2. Telnet 226
12.3. FTP file transfer protocol 227
12.4. SMTP protocol 229
12.5. RPC protocol and port mapping 232
12.6. Network file system NFS 235
12.7. Storage network 236
12.8. Report on HTTP hypertext documents 239
12.8.1. HTML and XML languages 241
12.8.2. WAP and WML 247
12.9. Internet radio 248
12.10. Television on the IP 249 network
12.11. Calls over IP 250
12.12. Other applications 251
12.13. Exercises 255
13. Security problems 256
13.1. Introduction 256
13.2. Network attacks 257
13.2.1. SYN Flooding 257
13.2.2. Distributed denial of service 258
13.2.3. Program attacks 258
13.2.4. Malware 259
13.2.5. Social engineering 260
13.3. Firewalls 261
13.4. Security and identity confirmation in the IP 262 protocol
13.5. Security of data and network link layers and authentication 264
13.5.1. PPTP and L2TP protocols 264
13.5.2. IPSec 265 protocol
13.6. Transport layer security and authentication 268
13.7. Exercises 269
Appendix A. Sample programs 271
A.1. TCP 271 server
A.2. TCP 273 client
A.3. UDP 275 server
A.4. UDP customer 276
Appendix B. Useful links 279
Appendix C. Acronyms 280
Index 288