| preface xix chapter 1 introduction to communications, standards, and protocols 1.1 why study communications? 1 a brief history 1 applications 4 issues 8 1.2 computer networks 9 common bus topology 10 star topology 11 ring topology 12 fully connected topology 13 combined topologies 13 1.3 standards and standards organizations 15 the need for standards 15 standards organizations 16 1.4 open systems and the osi model 18 overview of the model 22 connection strategies 24 physical layer 29 data link layer 30 .network layer 32 transport layer 33 session layer 36 presentation layer 38 application layer 40 intemet layers 42 summary 42 1.5 the future of data communications 44 review questions 51 exercises 52 references 53 chapter 2 transmission media and codes 2.1 introduction s4 2.2 conductive metal 57 twisted pair 57 coaxial cable 59 2.3 optical fiber 61 2.4 wireless communications 66 microwave transmission 67 satellite transmission 70 geosynchronous satellites 71 low earth orbit satellites 77 wireless lans 81 bluetooth 82 free space optics 83 summary 84 2.5 codes 87 early codes 87 ascii code 89 ebcdic code 92 unicode 92 2.6 summary 93 review questions 94 exercises 95 references 96 chapter 3 analog and digital signals 3.1 introduction 97 3.2 digital encoding schemes 98 nrz encoding 98 manchester encoding 100 3.3 analog signals 101 fourier's results 103 applications of fourier's results 106 3.4 bit rate 107 the nyquist theorem and noiseless channels 107 noisy channels 109 shannon's result 110 3.5 digital-to-analog conversion 112 frequency modulation 113 amplitude modulation 114 phase modulation 114 quadrature amplitude modulation 115 3.6 analog-to-digital conversion 118 pulse amplitude modulation 119 pulse code modulation 119 3.7 modems 121 signal constellation 122 modem standards 125 cable modems 127 3.8 dsl 131 how it works 132 different dsl technologies , 135 adsl lite (g. lite, itu standard itu g. 992.2) 135 sdsl 136 hdsl and hdsl2 136 shdsl 137 radsl 137 idsl 137 vdsl 137 3.9 summary 138 review questions 139 exeroses 141 references 143 chapter 4 making connections 144 4.1 introduction 144 4.2 communication carriers and devices 145 the telephone system 145 call routing 147 private branch exchanges 148 cellular phones 149 fax machines 151 4.3 transmission modes 153 serial and parallel transmission 153 asynchronous, synchronous, and isochronous transmission 154 simplex, half-duplex, and full-duplex communications 158 4.4 interface standards 159 eia-232 interface 160 eia-232 subsets 162 null modems 163 x.21 interface 164 usb 166 usb connections 166 data transfer 168 usb packets 170 firewire 172 connections 173 communications 175 arbitration 176 4.5 multiplexing 178 frequency-division multiplexing 180 time-division multiplexing 182 statistical multiplexers 183 wave-division multiplexing 185 4.6 digital carriers 186 tl 186 sonet 188 device types 189 payloads and frames 191 4.7 contention protocols 195 aloha protocols 196 cartier sense multiple access 199 collision detection 202 collision avoidance 205 token passing 205 summary of protocols 207 4.8 summary 207 renew questions 210 exercises 212 references 214 chapter 5 data compression 215 5.1 introduction 215 5.2 frequency-dependent codes 217 huffman code 217 arithmetic compression 220 5.3 run-length encoding 225 runs of the same bit 225 runs with different characters 226 facsimile compression 226 5.4 relative encoding 229 5.5 lempel~ziv compression 229 5.6 image compression 235 image representation 235 jpeg compression 238 dct phase 238 encoding phase 244 gif files 245 5.7 multimedia compression 246 mpeg 246 mp3 251 5.8 summary 254 review questions 254 exercises 255 references 257 chapter 6 data integrity 258 6.1 introduction 258 6.2 simple error detection techniques 259 parity checks 259 analysis of parity checking 260 checksums 261 6.3 cyclic redundancy checks for error detection 261 polynomial division 262 how crc works 263 analysis of crc 265 crc implementation using circular shifts 268 6.4 hamming codes: error correction 270 single-bit error correction 270 multiple-bit error correction 273 6.5 summary 274 renew questions 275 exercises 276 references 277 chapter7 data security 279 7.1 introduction 279 7.2 encryption algorithms 281 caesar cipher 282 polyalphabetic cipher 284 transposition cipher 284 bit-level ciphering 285 data encryption standards 287 des 287 triple des 291 aes and the rijndael algorithm 292 clipper chip and the skipjack algorithm 296 7.3 key distribution and protection 299 shamir's method 300 diffie-hellman key exchange 300 7.4 public key encryption 302 rsa algorithm 302 digital signatures 305 authentication and message digests 308 pretty good privacy 311 7.5 transport layer security and server authentication 315 transport layer security 316 x.509 certificate 317 handshakes 320 7.6 firewalls 323 packet filtering 324 application-level gateway 325 stateful inspection 327 7.7 viruses 329 infecting files 330 memory-resident viruses 332 virus evolution 333 virus sources 335 7.8 threats and attacks 336 the intemet worm 336 computer hackers 338 other threats 339 7.9 summary 341 renew questions 345 exercises 346 references 348 chapter 8 flow control 350 8.1 introduction 350 8.2 signaling 352 dte-dce flow control 353 x-on/x-off 353 8.3 frame-oriented control 354 unrestricted protocol 355 stop-and-wait protocol 356 protocol efficiency 358 8.4 go-back-n: a sliding window protocol 360 frame format 362 features 363 algorithm 366 8.5 selective repeat: a sliding window protocol 370 features 370 algorithm 374 8.6 efficiency of sliding window protocols 377 8.7 protocol correctness 380 finite state machines 380 std for a simplified go-back-n protocol 381 state transition diagram for a faulty go-back-n protocol 383 petri nets 386 8.8 summary 390 renew questions 392 exercises 393 references 395 chapter 9 local area networks 396 9.1 introduction 396 9.2 data link control 398 high-level data link control protocol 400 frame format 402 hdlc example 405 binary synchronous communications protocol 408 9.3 ethernet: ieee standard 802.3 410 concepts 411 ethernet frame format 413 physical implementations of 10 mbps ethernet 415 9.4 fast ethernet (100 mbps) 417 100basetx 418 100basefx 421 100baset4 422 collision domain 424 9.5 gigabit ethernet 424 mac sublayer 425 1000basex 427 1000baset 428 beyond gigabit rates 430 9.6 token ring: ieee standard 802.5 433 token and frame formats 434 reserving and claiming tokens 436 ring maintenance 440 9.7 wireless networks: ieee standard 802.11 443 infrared and radio waves 444 contention 447 addressing 449 frame format 451 wired equivalent privacy 453 variations of 802.11 454 9.8 summary 455 review questions 457 exercises 459 references 461 chapter 10 connecting networks 462 10.1 introduction 462 10.2 layer 1 connections 465 repeaters and hubs 465 10.3 layer 2 connections 467 bridges 467 bridging different types of lans 468 routing 469 routing tables 469 transparent bridges 471 route learning 471 frame propagation 473 spanning tree algorithm 475 source-routing bridges 479 switches and switched ethernet 480 virtual lans 484 10.4 layer 3 connections 487 routing tables 488 centralized routing 490 distributed routing 491 static routing 492 adaptive routing 492 10.5 dijkstra's algorithm 493 10.6 the bellman-ford algorithm 496 problems with the bellman-ford algorithm 500 10.7 additional routing methods 502 link state routing 502 hierarchical routing 503 routing information protocol 506 open shortest path first 509 border gateway protocol 510 summary of routing techniques 512 10.8 congestion and deadlock 512 congestion 512 deadlock 515 10.9 summary 517 review questions 519 exercises 520 references 523 chapter 11 internet protocols and applications 524 11.1 introduction 524 11.2 internet protocol 525 overview of tcp/ip 526 internet addressing 528 classless addresses 531 obtaining an address 533 domain name system 534 ip packets 537 fragmentation 540 ip routing 541 routers 546 multicast routing 549 resource reservation protocol 555 internet control message protocol 557 11.3 ipv6 559 ip shortcomings 560 packet headers 561 ipsec 564 lpv6 addressing 566 compatibility with ipv4 569 summary 570 11.4 transport protocols 571 transmission control protocol 573 tcp segment 574 connection management 577 flow control 580 congestion control 582 user datagram protocol 584 real-time transfer protocol 585 11.5 internet applications 589 virtual terminal protocols 589 telnet 590 secure shell 593 file transfers 596 ftp 597 secure copy 600 simple mail transfer protocol 600 simple network management protocol 604 management information base 605 snmp commands 606 11.6 summary 608 review questions 610 exercises 612 references 614 chapter 12 internet programming 616 12.1 introduction 616 12.2 socket programming 617 sockets 618 client/server model 619 socket data structures 620 socket commands 621 client/server example 621 client source code 624 server source code 631 12.3 world wide web 633 web page access 634 hypertext markup language 636 tags 637 html forms 641 client-side programming and javascript 644 12.4 common gateway interface and server-side programming: setting up a search engine 649 forms 650 query strings 651 example search engine 651 12.5 perl programming: pizza ordering system 654 customer interaction 655 verifying phone numbers 658 updating customer information 665 placing an order 668 verifying the order 669 12.6 summary 672 review questions 673 exercises 674 references 676 chapter 13 circuit technologies 677 13.1 introduction 677 13.2 integrated services digital network 678 services 679 architecture 681 protocols 683 signaling system 7 684 basic service protocols 686 call setup 689 broadband isdn 691 13.3 virtual circuit protocols: x.25 and frame relay 692 packet-switched network modes 693 virtual circuits 693 datagram service 695 x.25 interface standard 696 packet format 697 virtual calls 698 frame relay 699 frame format 701 committed information rate 702 congestion control 703 13.4 asynchronous transfer mode 705 benefits of small fixed-size cells 706 overview of atm network 708 switching 709 banyan switches 710 reference model 712 cell definition 713 header error control 714 cell loss priority 716 payload type 716 virtual circuits and paths 716 connection management 717 connection parameters 719 adaptation layers 720 aal 1 721 aal 2 723 aal 5 724 service-specific connection-oriented protocol 725 gigabit ethernet versus atm 726 13.5 summary 727 renew questions 727 exercises 729 references 730 glossary acronyms index |
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