Computer Networks

Computer Networks is designed as a textbook for undergraduate students of computer science engineering as well as students pursuing courses MCA and IT. The book covers the fundamentals of Computer Networks and provides the tools that will help in simplifying the concepts and protocols for the students. Beginning with network fundamentals such as types of networks, network components etc, and an overview of data communications, the books moves on to provide a layer approach to building a computer network. Exhaustive description of the physical layer, data link layer, medium access sub layer, transport layer, and application layer is provided. The book also provides separate coverage of security issues. Key concepts of OSI model, its layers and their applications, TCP/IP, UDP, fiber optic communication, IEEE 802 wireless standard, various network protocols, and other advanced concepts are covered in detail. Using a simple approach with plenty of interesting analogies, the book provides a rich mix of examples and exercises to help students assimilate the theory.

Table of Contents:
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