Computer Networks

1.1 THE NEED TO SHARE RESOURCES; 1.2 CONCEPT OF LAYERING; 1.2.1 LAYERING EXAMPLE; 1.2.2 ADVANTAGES OF LAYERING MECHANISM; 1.2.2.1 DIVISION OF WORK; 1.2.2.2 STANDARD INTERFACING BETWEEN COMPONENTS; 1.2.2.3 REPLACING A COMPONENT IS EASY; 1.2.2.4 INDEPENDENCE IN PROTOCOL DESIGN; 1.2.3 DISADVANTAGES OF LAYERING; 1.2.3.1 SPEED AND PERFORMANCE ARE REDUCED; 1.2.3.2 MEMORY USAGE INCREASED; EX. SENSOR NETWORKS NODE; 1.2.4 THE TCP/IP AND OSI LAYERING MODELS; 1.2.5 THE OSI MODEL; 1.2.6 THE TCP/IP MODEL; 1.2.7 CONNECTION ORIENTED VS. CONNECTIONLESS TRANSFER; 1.2.8 THE DIFFERENCE BETWEEN TCP/IP AND OSI MODELS; 1.2.9 THE TOP DOWN AND BOTTOM UP APPROACHES FOR STUDYING LAYERS; 1.2.10 FUNCTIONS OF EACH LAYER; 1.2.10.1 THE PHYSICAL LAYER; 1.2.10.2 THE DATA LINK LAYER; 1.2.10.3 THE NETWORK LAYER; 1.2.10.4 THE TRANSPORT LAYER; 1.2.10.5 THE APPLICATION LAYER; 1.2.10.6 THE ENTIRE COMMUNICATION PROCESS; 1.3 DISTRIBUTED SYSTEMS AND NETWORKS; 1.4 PEER-TO-PEER AND CLIENT SERVER NETWORKS; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 2 INTRODUCTION; 2.1 PREREQUISITE TO THE DEFINITION OF THE NETWORK; 2.2 DEFINITION: NETWORK; 2.3 NETWORK CATEGORIES; 2.3.1 DIVISION BASED ON PERIPHERY; 2.3.1.1 PERSONAL AREA NETWORKS; 2.3.1.2 LOCAL AREA NETWORKS; 2.3.1.3 METROPOLITAN AREA NETWORK AND WIDE AREA NETWORK; 2.3.1.4 INTERNETWORKS; 2.3.2 DIVISION BASED ON CONNECTION; 2.3.2.1 WIRED NETWORKS; 2.3.2.2 WIRELESS NETWORKS; MANETS; SENSOR NETWORKS; 2.3.3 DIVISION BASED ON COMMUNICATION TYPE; 2.3.3.1 BROADCAST NETWORKS; 2.3.3.2 POINT TO POINT NETWORKS; 2.3.4 DIVISION BASED ON USAGE; 2.3.4.1 HOME NETWORKS: THE USAGE; 2.3.4.2 SENSOR NETWORKS: THE USAGE; 2.3.4.3 OTHER TYPES OF CATEGORIZATION OF NETWORKS; 2.4 NETWORK COMPONENTS; 2.4.1 THE NETWORK INTERFACE CARD OR LAN CARD; 2.4.2 WIRE FOR WIRED CONNECTION; 2.4.3 FREQUENCY BAND FOR WIRELESS TRANSMISSION; 2.4.4 THE SERVERS AND THE NODES; 2.4.5 INTERCONNECTING DEVICES; 2.4.5.1 HUB; 2.4.5.2 SWITCH; 2.4.5.3 REPEATER; 2.4.5.4 BRIDGE; 2.4.5.5 ROUTER; 2.5 THE CONNECTION; 2.5.1 THE PHYSICAL CONNECTION; 2.5.1.1 CONNECTION BY THE NETWORK INTERFACE CARD; 2.5.1.2 OTHER TYPES OF CONNECTION; SERIAL CONNECTION; PARALLEL CONNECTION; UNIVERSAL STANDARD BUS (USB) CONNECTION; 2.5.2 THE LOGICAL CONNECTION; 2.5.2.1 CONNECTION ORIENTED CONNECTION; 2.5.2.2 CONNECTIONLESS CONNECTION; 2.5.2.3 CONNECTION ORIENTED CONNECTION ON TOP OF CONNECTIONLESS CONNECTION; 2.5.2.4 CONNECTIONLESS CONNECTION ON TOP OF CONNECTIONLESS CONNECTION; 2.5.2.5 ADDRESSING ISSUES; 2.6 LAYERS AND SERVICES; 2.6.1 DESIGN OF LAYERS AS SERVICE PROVIDERS AND USERS; 2.6.2 STANDARDIZATION OF SERVICES; 2.6.3 QUALITY OF SERVICE ISSUES; 2.7 USERS AND SERVICES; 2.7.1 DESIRED CHARACTERISTICS OF AN APPLICATION LAYER; 2.7.1.1 API OR GUI; 2.7.1.2 USER FRIENDLINESS; 2.7.1.3 CONCURRENCY CONTROL; 2.8 THE PROTOCOLS; 2.8.1 THE STANDARDIZATION BODIES; 2.8.2 CONNECTION AND PROTOCOL; 2.8.3 CONNECTIONLESS AND CONNECTION ORIENTED PROTOCOLS; 2.8.4 LAYERS AND PROTOCOLS; 2.8.4.1 DIFFERENTIATING BETWEEN INTERFACES AND PROTOCOLS; 2.8.4.2 NEED FOR PEERS TO COMMUNICATE; 2.9 APPLICATIONS OF COMPUTER NETWORKS; 2.9.1 TYPES OF NETWORK APPLICATIONS; 2.9.2 HOME NETWORKING APPLICATIONS; 2.9.3 MOBILE NETWORKING APPLICATIONS; 2.9.4 WIRELESS NETWORKING APPLICATIONS; 2.10 SECURITY ISSUES; 2.10.1 HIDDEN DANGERS; 2.10.2 POLICY ISSUES; 2.10.3 THE DILEMMA OF USER CONVENIENCE VS. SAFER STATE OF A NETWORK; 2.10.4 SOCIAL ENGINEERING; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 3.1 DATA COMMUNICATION BASICS; 3.2 THE BANDWIDTH, THE DATA RATE AND LIMITING FACTORS; 3.2.1 THE FREQUENCY AND THE BAND; 3.2.2 THE MEDIA EFFECT ON THE BANDWIDTH OF THE SIGNAL; 3.2.3 THE COMPOSITE SIGNALS AND FOURIER COMPONENTS; 3.2.4 THE BANDWIDTH, HARMONICS, NOISE AND MAXIMUM DATA RATE OF A CHANNEL; 3.2.5 FILTERS; 3.3 ANALOG AND DIGITAL SIGNALING; 3.3.1 ANALOG SIGNALING; 3.3.2 DIGITAL SIGNALING; 3.3.3 DIFFERENCE; 3.4 ANALOG AND DIGITAL TRANSMISSION; 3.4.1 INTRODUCTION TO TRANSMISSION; 3.4.2 ANALOG TRANSMISSION; 3.4.3 DIGITAL TRANSMISSION; 3.5 CODING MECHANISMS; 3.6 MODULATION; 3.6.1 AMPLITUDE MODULATION; 3.6.1.1 DIGITAL SIGNALING AND ERRORS; 3.6.2 FREQUENCY MODULATION; 3.6.3 THE PHASE MODULATION; 3.7 MODULATION IN PRACTICE; 3.7.1 MODULATION IN CABLE TV; 3.7.2 MODULATION IN ADSL; 3.8 MULTIPLEXING AND DE-MULTIPLEXING; 3.9 TIME DIVISION MULTIPLEXING; 3.10 FREQUENCY DIVISION MULTIPLEXING; 3.11 SWITCHING AND ROUTING; 3.12 TRANSMISSION AND ERRORS; 3.12.1 ATTENUATION; 3.12.2 DISTORTION; 3.12.3 NOISE; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 4.1 INTRODUCTION; 4.2 THE DUTIES OF PHYSICAL LAYER; 4.2.1 MACHINE PORT LEVEL ADDRESSING; 4.2.2 TRANSFERRING BITS; 4.2.3 SYNCHRONIZING SENDER AND RECEIVER; 4.2.4 MULTIPLEXING MULTIPLE DATA STREAMS; 4.2.5 INAPPROPRIATENESS OF FDM AND TDM FOR BURSTY DATA; 4.2.6 THE ELECTROMAGNETIC SPECTRUM; 4.2.7 RADIO WAVES; 4.2.8 MICROWAVES; 4.3 INFRARED AND MILLIMETER WAVES; 4.4 THE ISM BANDS; 4.5 THE OPTICAL LIGHT AND FREE SPACE OPTICS; 4.6 WIRED PHYSICAL LAYER; 4.6.1 THE UTP CABLE; 4.6.2 THE TOTAL INTERNAL REFLECTION PRINCIPLE; 4.6.3 THE FIBER OPTIC CABLE; 4.6.4 DESIGN OF FIBER CABLES; 4.6.5 SENDING AND RECEIVING DEVICES; 4.6.6 COMPARISON WITH UTP; 4.6.7 OTHER CABLES; 4.7 WIRELESS PHYSICAL LAYER; 4.7.1 TWO SPECIAL CASES, HIDDEN AND EXPOSED STATION; 4.7.2 SOLUTION TO THE HIDDEN AND EXPOSED STATION PROBLEM; 4.7.3 COMPONENTS OF THE WIRELESS SYSTEM; 4.7.4 ANTENNAS; 4.7.5 ACCESS POINTS; 4.7.6 WIRELESS LAN; 4.7.7 THE 802.11 STANDARD; 4.7.8 AD HOC AND INFRASTRUCTURE MODES; 4.7.9 802.11 PHYSICAL LAYER; 4.7.9.1 THE 802.11B; 4.7.9.2 THE OFDM AND THE 802.11A; 4.7.9.3 THE 802.11G; 4.7.9.4 THE 802.16 PHYSICAL LAYER; 4.7.9.5 802.16D, THE STANDARD FOR FIXED WIRELESS BROADBAND; 4.7.9.6 ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS (OFDMA) AND 802.16E; 4.7.10 WIRELESS COMMUNICATION USING SATELLITE; 4.7.10.1 THREE DIFFERENT ORBITS; LEO FOR DATA COMMUNICATION; 4.8 THE TELEDESIC AND GLOBALSTAR; 4.9 PHYSICAL LAYER BASED ON TELEPHONE LINE; 4.9.1 THE TELEPHONE; 4.9.2 THE XDSL; 4.9.3 DISCRETE MULTITONE: STANDARD FOR ADSL AND VDSL; 4.10 CABLE INTERNET; 4.11 WHITESPACES; KEYWORDS; POINTS TO REMEMBER; EXERCISES; CHAPTER 5: THE DATA LINK LAYER; 5.1 DUTIES OF DATA LINK LAYER; 5.1.1 THE NO MONOPOLY IDEA AND THE FRAMING; 5.1.2 FRAMING TECHNIQUES; 5.1.2.1 FRAMING USING FLAG BYTE AND STUFF USING BYTE STUFFING; FRAMING BY FLAG BYTE AND BIT STUFFING; FRAMING BY USING ILLEGAL COMBINATIONS; CHARACTER COUNT WITH OTHER METHODS; 5.2 THE ERROR; 5.2.1 TYPE OF ERRORS; 5.2.2 THE ERROR HANDLING; 5.2.3 REDUNDANCY: THE FUNDAMENTAL NEED FOR ERROR HANDLING; 5.2.4 ERROR IS NOT ALWAYS HANDLED AT DLL; 5.2.5 ERROR DETECTION; 5.2.5.1 CHECKSUM; 5.2.5.2 CYCLIC REDUNDANCY CHECK; MODULO 2 ARITHMETIC; THE DIVISION PROCESS; OTHER IMPORTANT PROPERTIES; 5.2.6 ERROR CORRECTION; 5.2.7 WHAT IS MORE IMPORTANT, CORRECTION OR DETECTION?; 5.2.8 THE FLOW CONTROL; 5.2.9 THE SERVICES FROM PHYSICAL AND TO NETWORK LAYERS; 5.2.10 LOCAL MACHINE LEVEL ADDRESSING; 5.2.11 MULTIPLEXING AND DEMULTIPLEXING; 5.3 THE PROTOCOLS; 5.3.1 THE SENDER AND RECEIVER CONCEPT; 5.3.2 THE ACKNOWLEDGEMENT; 5.3.3 THE TIMERS AND TIME OUT EVENT; 5.3.4 THE SENDING AND RECEIVING WINDOWS AND ACKS; 5.3.5 THE SEQUENCE AND ACKNOWLEDGEMENT NUMBERS; 5.3.6 RETRANSMISSION; 5.3.7 DUPLICATE FRAMES; 5.3.8 GO BACK N; 5.3.9 SELECTIVE REPEAT; 5.3.10 PREREQUISITES FOR CODING PROTOCOLS; 5.3.10.1 PROTOCOL 1; 5.3.10.2 PROTOCOL 2; 5.3.10.3 PROTOCOL 3; 5.3.10.4 PROTOCOL 4; 5.3.10.5 PROTOCOL 5 - GO BACK N; 5.3.10.6 PROTOCOL 6; 5.3.10.7 THE NEED FOR PROCESS TO PROCESS COMMUNICATION; 5.3.10.8 INTRODUCTION TO NAMED PIPES; 5.3.10.9 IMPLEMENTATION FOR TIMERS; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 6.1 INTRODUCTION; 6.1.1 SHARED CHANNEL CONCEPT; 6.1.2 COLLISION DETECTION AND AVOIDANCE; 6.1.3 CHANNEL ACQUISITION ISSUES; 6.1.4 ADHOC AND INFRASTRUCTURE MODES; 6.2 WIRED MAC LAYER; 6.2.1 THE PREREQUISITE TO ETHERNET, ALOHA AND SLOTTED ALOHA; 6.2.2 THE ETHERNET; 6.2.2.1 CLASSIC ETHERNET; TYPES OF CONNECTIONS; ETHERNET TOPOLOGY; FRAME STRUCTURE; CSMA/CD PRINCIPLE AND IMPLEMENTATION; LIMITATIONS OF CSMA/CD; THE BINARY EXPONENTIAL BACK OFF ALGORITHM; USING SWITCH INSTEAD OF HUBS; 6.2.3 FAST ETHERNET; 6.2.3.1 TYPES OF CONNECTION; 6.2.3.2 THE PARADIGM SHIFT, POINT TO POINT FROM SHARED; 6.2.4 THE GIGABIT ETHERNET; 6.2.4.1 MODES OF OPERATION; 6.2.4.2 TYPES OF CONNECTIONS; 6.2.4.3 HANDLING LONGER RANGE; CAREER OR HARDWARE EXTENSION; FRAME BURSTING; 6.2.4.4 THE 8B/10B CODING; 6.2.4.5 4B/5B ENCODING; 6.2.4.6 FLOW CONTROL; 6.2.5 THE 10GB ETHERNET; 6.2.5.1 TYPES OF CONNECTIONS; 6.2.6 FUTURE VERSIONS; 6.2.7 DUAL SPEED CARDS, AUTO NEGOTIATION AND UPGRADES; 6.3 802.2, THE LOGICAL LINK CONTROL (LLC) LAYER; 6.4 WIRELESS MAC LAYER; 6.4.1 THE WIRELESS LAN PROTOCOL (802.11); 6.4.2 ADHOC OR DCF MODE; 6.4.3 FRAGMENTATION IN DCF MODE; 6.4.4 PCF OR INFRASTRUCTURE MODE; 6.4.4.1 ACCESS POINTS (APS) AND SERVICE PRIMITIVES; 6.4.5 MANAGING PCF AND DCF MODES TOGETHER; 6.4.6 THE 802.11 FRAME; 6.4.7 FRAME CONTROL; 6.4.8 DURATION; 6.4.9 DSS AND FOUR ADDRESS FIELDS; 6.4.10 INTRA-CELL AND INTER-CELL TRANSMISSION; 6.4.11 SEQUENCE, PAYLOAD AND CRC FIELDS; 6.4.12 WIRELESS BROADBAND; 6.4.13 THE WIRELESS BROADBAND PROTOCOL (802.16) SUB LAYERS; 6.5 THE MAC LAYER; 6.5.1 SERVICE CLASSES (OR FLOWS); 6.6 THE GENERIC FRAME STRUCTURE; 6.7 CONNECTING DEVICES AT DATA LINK LAYER; 6.8 BRIDGES; 6.8.1 THE AUTO CONFIGURATION AND MANAGEABILITY; 6.8.2 PARALLEL BRIDGES AND SPANNING TREE SOLUTION; 6.8.3 REMOTE BRIDGES; 6.9 CONNECTING HETEROGENEOUS NETWORKS; 6.10 THE VIRTUAL LAN; 6.11 THE IEEE 802.1Q STANDARD; 6.12 THE VLAN OPERATION; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 7.1 INTRODUCTION; 7.2 NETWORK LAYER DUTIES; 7.2.1 ROUTING; 7.2.2 ACCOUNTING; 7.2.3 RECEIVE SERVICE FROM DATA LINK LAYER; 7.2.4 PROVIDE SERVICE TO TRANSPORT LAYER; 7.2.5 GLOBAL MACHINE LEVEL ADDRESSING; 7.2.6 MULTIPLEXING AND DEMULTIPLEXING MULTIPLE TRANSPORT LAYER CONNECTIONS; 7.2.7 MULTIPLEXING AND DE-MULTIPLEXING DATA LINK LAYER CONNECTIONS; 7.3 CONNECTION ORIENTED FORWARDING USING VIRTUAL CIRCUITS; 7.4 CONNECTIONLESS FORWARDING USING DATAGRAMS; 7.5 CONNECTION ORIENTED VS. CONNECTIONLESS FORWARDING; 7.6 EXAMPLE; 7.6.1 COMPARISON; 7.7 ROUTING ALGORITHMS; 7.7.1 REQUIREMENTS OF A GOOD ROUTING ALGORITHM; 7.7.1.1 DYNAMISM AND FLEXIBILITY; 7.7.1.2 PERFORMANCE; 7.7.1.3 ROBUSTNESS; 7.7.2 INTERNAL AND EXTERNAL ROUTING ALGORITHMS; 7.7.3 DISTANCE VECTOR ROUTING; 7.7.3.1 HOW THE ROUTING TABLE IS CONSTRUCTED; 7.7.3.2 EXAMPLE; 7.7.3.3 THE COUNT TO INFINITY PROBLEM; 7.7.4 LINK STATE ROUTING; 7.7.4.1 COLLECTING INFORMATION FROM OTHER ROUTERS AND ESTIMATING THE AS TOPOLOGY; 7.7.4.2 FINDING NEIGHBORS AND DELAY; 7.7.4.3 SEQUENCE NUMBER AND AGE FIELDS; 7.7.4.4 ROUTING TABLE CONSTRUCTION; 7.7.5 ROUTING IN MANET; 7.7.5.1 ROUTE DISCOVERY OPERATION; 7.7.5.2 ROUTE MAINTENANCE; 7.7.6 BORDER GATEWAY PROTOCOL; 7.7.6.1 THE BGP OPERATION; 7.8 HIERARCHICAL ROUTING; 7.9 BROADCAST ROUTING; 7.10 MULTICAST ROUTING; 7.11 CONGESTION; 7.11.1 CONGESTION CONTROL; 7.11.2 CONGESTION CONTROL ALGORITHMS; 7.11.2.1 ADMISSION CONTROL; 7.11.2.2 PREVENTION OF CONGESTED ROUTES; 7.11.2.3 DROPPING PACKETS AND RED (RANDOM EARLY DISCARD); 7.11.2.4 JITTER CONTROL; 7.12 NETWORK LAYER SWITCHING; 7.12.1 MULTI PROTOCOL LABEL SWITCHING (MPLS); 7.13 INTERNETWORKING ISSUES; 7.13.1 HETEROGENEITY IN NETWORKS; 7.13.2 FRAGMENTATION; 7.13.3 TUNNELING; 7.14 SECURITY ISSUES AT NETWORK LAYER AND IPSEC; 7.14.1 OVERVIEW OF IPSEC; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 8.1 INTRODUCTION; 8.2 TRANSPORT LAYER DUTIES; 8.2.1 MULTIPLEXING, DEMULTIPLEXING AND PORT NUMBERS; 8.2.2 SERVICE TO APPLICATION LAYER; 8.2.3 DESIRABLE SERVICES NOT PROVIDED BY INTERNET TRANSPORT LAYERS; 8.2.4 PROCESS LEVEL ADDRESSING; 8.2.5 PROVIDING END-TO-END SOLUTIONS; 8.2.5.1 FLOW CONTROL; 8.2.5.2 MANAGING MULTIPLE CONNECTIONS DYNAMICALLY; 8.2.5.3 TIMER MANAGEMENT; 8.2.5.4 SESSION CONTROL; RETRANSMISSION, RTT AND TIMEOUT CALCULATIONS; OTHER TIMERS; 8.3 CONNECTION MANAGEMENT IN TRANSPORT LAYER; 8.3.1 THE DELAYED DUPLICATE PROBLEM; 8.3.2 THE CONNECTION ESTABLISHMENT; 8.3.3 THE THREE WAY HANDSHAKE; 8.3.4 CONNECTION ESTABLISHMENT IN TCP; 8.3.5 THE CONNECTION RELEASE; 8.4 CONGESTION CONTROL; 8.4.1 DETECTION; 8.4.2 REACTING TO CONGESTION USING RED; 8.4.5 FAST RECOVERY, MDCA AND AIMD; 8.4.4 FLOW CONTROL; 8.5 COMPARISON WITH DATA LINK LAYER; 8.6 CLIENT SERVER COMMUNICATION; 8.6.1 PROBLEMS AND SOLUTIONS; 8.6.2 SOCKETS AND COMMUNICATION USING SOCKETS; 8.6.2.1 TCP STATE TRANSITION DIAGRAM; 8.7 A SAMPLE CLIENT SERVER PROGRAM; 8.8 OTHER ISSUES; 8.8.1 BUFFER MANAGEMENT; 8.8.2 CRASH RECOVERY; 8.8.3 PERFORMANCE; 8.9 NONSTANDARD PERFORMANCE IMPROVEMENT PROCEDURES; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 9.1 INTRODUCTION; 9.2 DOMAIN NAME SYSTEM; 9.2.1 THE DOMAIN NAMESPACE; 9.2.1.1 ADVANTAGES OF HIERARCHY; 9.2.1.2 THE DISTRIBUTED DATABASE; 9.2.1.3 SEARCH MECHANISM AND NAME RESOLUTION; 9.2.1.4 THE ZONE; 9.2.2 THE REGISTRATION PROCESS; 9.2.3 THE NAME SERVERS; 9.2.4 THE RESOURCE RECORDS; 9.2.5 DIFFERENT TYPES OF RESOURCE RECORDS; 9.2.6 DDNS (DYNAMIC DNS); 9.2.6.1 THE DNSSEC; 9.3 THE WORLD WIDE WEB AND HTTP; 9.3.1 THE HTTP QUERY AND RESPONSE; 9.3.2 THE STRUCTURE OF THE QUERY AND RESPONSE; 9.3.3 OTHER METHODS; 9.3.4 PERSISTENT CONNECTION WITH HTTP 1.1; 9.3.5 COOKIES TO MAKE BROWSER MORE USER FRIENDLY; 9.3.6 SESSION VARIABLES; 9.3.7 THE CONDITIONAL DOWNLOAD; 9.3.8 PROXIES AS INTERMEDIARIES; 9.3.9 THE DYNAMIC WEB; 9.3.10 THE EMAIL SYSTEM; 9.3.11 INTRODUCTION TO SMTP AND COMPONENTS OF EMAIL SYSTEM; 9.3.12 MAIL BOXES, MAIL ALIASES AND ALIAS EXPANSION; 9.3.13 THE USER AGENT; 9.3.14 INTERNET MAIL STANDARD FOR MAIL CONTENT: - RFC 2822; 9.3.15 MTA AND THE SMTP, THE MESSAGE TRANSFER STANDARD OF INTERNET; 9.3.16 IMT (INTERNET MEDIA TYPES); 9.3.17 SMTP AND HTTP, A COMPARISON; 9.3.18 BASE64 AND QUOTED PRINTABLE ENCODING; 9.3.19 THE INTERMEDIARIES USED IN MAILING; 9.3.20 THE POP3 AND IMAP; 9.3.21 THE WEB-MAIL; 9.3.22 FILTERS AND SPAM; 9.4 THE FILE TRANSFER PROTOCOL (FTP); 9.5 THE CONTROL AND DATA CONNECTIONS; 9.6 FTP PORT NUMBERS; 9.7 7 BIT NVT ASCII- THE FORMAT FOR DATA TRANSFER; 9.8 ACCESSING FTP USING MENU DRIVEN PROGRAMS AND BROWSERS; 9.9 ANONYMOUS FTP; 9.10 SECURE FTP, SSL-FTP; KEYWORDS; POINTS TO REMEMBER; EXERCISES; 10.1 INTRODUCTION; 10.2 CRYPTOGRAPHY; 10.2.1 THE CONVENTIONAL SECURITY MODEL; 10.2.2 SUBSTITUTION AND TRANSPOSITION; 10.2.3 SYMMETRIC KEY ALGORITHMS; 10.2.3.1 SUBSTITUTION CIPHER AND SBOX; 10.2.3.2 TRANSPOSITION CIPHER AND PBOX; 10.2.4 BLOCK CIPHERS; 10.2.4.1 DIGITAL ENCRYPTION STANDARD (DES); 10.2.4.2 TRIPLE DES; 10.2.4.3 ADVANCED ENCRYPTION STANDARD (AES); 10.2.5 ONETIME PADS; 10.2.6 QUANTUM CRYPTOGRAPHY; 10.2.6.1 TERMS RELATED TO QUANTUM CRYPTOGRAPHY; 10.2.6.2 THE WORKING OF BB84; 10.2.7 AVOIDING RANDOM AND REPLAY ATTACKS; 10.2.8 CIPHER MODES; 10.2.8.1 ELECTRONIC CODEBOOK MODE; 10.2.8.2 CIPHER CHAINING MODE; 10.2.8.3 CIPHER FEEDBACK MODE; 10.2.8.4 STREAM CIPHER; 10.2.8.5 COUNTER MODE; 10.3 CRYPTANALYSIS; 10.3.1 ATTACKING BLOCK CIPHERS; 10.4 PUBLIC KEY ALGORITHMS; 10.4.1.1 RSA; 10.4.1.2 WHY RSA WORKS?; 10.4.1.3 STRENGTH OF RSA; 10.4.1.4 OTHER METHODS; 10.4.1.5 THE KEY DISTRIBUTION ISSUES; 10.5 DIGITAL SIGNATURES; 10.5.1.1 SYMMETRIC KEY SIGNATURE; 10.5.1.2 PUBLIC KEY SIGNATURE; 10.5.1.3 MESSAGE DIGESTS; THE PREREQUISITE FOR THE DESIGN OF HASH FUNCTION; MD5; SHA-1; 10.5.1.4 THE BIRTHDAY ATTACK; 10.6 PUBLIC KEY MANAGEMENT; 10.6.1.1 CERTIFICATES AND X.509 STANDARD; 10.6.1.2 PUBLIC KEY INFRASTRUCTURE (PKI); DIRECTORIES; REVOCATION; 10.7 AUTHENTICATION PROTOCOLS; 10.7.1 AUTHENTICATION BASED ON SHARD SECRET KEY; 10.7.2 THE SHARED SECRET KEY USING HMAC; 10.7.3 THE DIFFIE-HELLMAN KEY EXCHANGE; 10.7.4 AUTHENTICATION USING A KEY DISTRIBUTION CENTER; 10.7.4.1 NEEDHAM-SCHROEDER PROTOCOL; 10.7.4.2 AUTHENTICATION USING KERBEROS; 10.7.5 AUTHENTICATION USING A PUBLIC KEY CRYPTOGRAPHY; 10.8 INFORMATION SECURITY; 10.8.1 VULNERABILITIES; 10.8.2 ATTACKS; KEYWORDS; POINTS TO REMEMBER; EXERCISES