ASSIGNMENT ON: INTRODUCTION TO INTERNET1) DEFINITION OF INTERNET & USES OF THE INTERNETInternet: Internet is a collection of Networks connected by internetworking devices such asrouter or gateway. The internet has its root in the ARPANET System of the US Department of Defense.Internet can be defined as a network of networks, which share a common mechanismfor addressing computers and a common set of communication protocols forcommunications between two computers on the network.Uses of the Internet: The world wide scope of the internet makes it perhaps, the single most valuable toolfor use in many significant ways by both non-profit and commercial organizations.Some important uses of the Internet are listed below: I. Online Communication: The E-mail service on the internet is extensively used today by computer users around the world to communicate with each other. II. Software Sharing: The internet provides access to a large number of shareware software development tools and utilities. The Free Software Foundations also provides a wealth of GNU software tools on the internet, that can be downloaded free of charge. III. Exchange of Views on Topics of Common Interest: The internet has a number of news groups. Each news groups allows a group of users to exchange their views on some topics of common interest. IV. Posting of Information of General Interest: It is often used as a large electronic bulletin board on which information of general interest can be posted to bring it to the attention of interested users. V. Product Promotion: Several commercial organizations are effectively using the internet services promoting their products. They mainly focused on information about corporate happenings, product announcements, recent strategy etc. VI. Customer Support: Many organizations are also using the internet to provide timely customer support.
VII. Online Journals & Magazines: The internet now has literally thousands of electronic subscriptions, which can be found both for free and low cost. VIII. World-wide Video Conferencing: World wide video conferencing is an emerging service on the internet which allows a group of users located around the globe to talk and interact with each other. IX. Online Degree & Courses: Recently internet uses as a medium of taking online degree and take part on different courses.2) SOME SHORT NOTES: WWW (World Wide Web) The World Wide Web (WWW) is the most popular and promising method of accessing the internet. WWW is a depositor of information linked together from points all over the world. Tim Burners Lee introduced it first. World first website is info.cern.ch. Hypertext: Hypertext or hyper is an information containing text that is linked to other documents through a point. An effectively designed hypertext document can help users rapidly locate the desired type of information on the internet. Webpage: Webpage is a unit of hypertext or hyper media available on the web. WebPages are created using a special language called Hypertext Markup Language. HTTP: HyperText Transfer Protocol (HTTP) is an application service for retrieving a web document. Any computer on the internet, which uses the HTTP protocol, is called a web server. File Transfer Protocol: File Transfer Protocol (FTP) is TCP/IP an application layer protocol that transfer files between two sites. DNS: Domain Name System or DNS is TCP/IP an application layer protocol that transfer file between two sites.
URL: Uniform Resource Locator (URL) is a string character that identifies a page on the WWW. It is an addressing scheme used by WWW browsers to locate sites on the internet. Protocol Host Port Path :// : / Example: http://www.wub.edu.bd/about.wub Subscriber Identity Module: Subscriber Identity Module (SIM) is a portable memory chip used in models of cellular phone. Telnet: Terminal Network that is Telnet is TCP/IP application layer protocol that transfer files between two sites.3) ELECTRONIC MAIL & ITS ADVANTAGES: Electronic mail is a system for exchanging data through a computer network. It allows an internet user to send a mail to another internet user in any part of the world in a near real time manner. All internet users have an e-mail address that identifies an individual user of an e- mail system and has a logical mailbox. When sending a mail to another user, the sender specifies the e-mail address of the receiver. Then the receiver extracts the mail from the mailbox and reads it’s at his convenient time. Advantages: With e-mail service, the internet has proved to be a rapid and productive communication tool for millions of users. As compared to paper mail, telephone or fax, e-mail is preferred by many because of its following advantages: I) It is faster than paper mail; II) Unlike the telephone, the persons communicating need not be available at the same time; III) E-mail documents can be stored in a computer memory and can be easily edited by using editing programs.
4) SERVER & CLIENT Server: A server is a computer or device on a network that manages network resources. It may store application software, database and data files for the network. In this case, it is usual to have one process, which owns the resource or service and is in charge of managing it. This process accepts requests from other process, which want to use resource or service. The process that owns the resource and does this management is called server process, the computer on which the server process runs is called a server computer. Client: A server or network server is a control computer that holds collection of data and programs for many PCs, workstation and other computers which are called clients. The entire network is called Client-Server network. Types of Servers: Several types of servers are described below: I. File Server: File server provides a central storage facility to store files of several users on the network.II. Database Server: Database server manages a centralized database and enables several users on the network to have shared access to the same database.III. Print Server: Print server manages one or more printers and accepts the process the print requests from any user in the network.IV. Name Server: Name Server translates names into network address enabling different computers on the network to communicate with each other. Some other servers are:V. Application Server: Application server occupy a large chunk of computing territory between database servers and the end user, and they often connect the two.VI. Audio/Video Server: Audio-video server bring multimedia capabilities to Web sites by enabling them to broadcast streaming multimedia content.
VII. Chat Server: Chat server enables a large number of users to exchange information in an environment similar to internet news groups that offer real tome discussion capabilities.VIII. Fax Server: A fax server is an ideal solution for organizations looking to reduce incoming and outgoing telephone resources but that need to fax actual documents. IX. FTP Servers: File Transfer Protocol makes it possible to move one or more files securely between computers while providing file securely between computers while providing file security and organization as well as transfer control. X. Mail Server: Mail server move and store mail over corporate networks via LAN and WAN and across the Internet. XI. Telnet Server: A telnet server enables users to log on to a host computer and perform tasks as if they’re working on the remote computer itself. 5) DEFINITION OF ROUTER & ITS CLASSIFICATION: Router: Router are designed to transmit data from one location to another via network, the router is responsible for doing the most work to ensure the data delivered. Types of Router: A) Wireless Router: Wireless routers have become popular in recent years because they allow connecting to a network from anywhere in home or office and don’t have the large mess of cables and wire which are associated with traditional wired network. B) Broadband Router: Broadband router is responsible for taking the features of a standard network switch and combining them with a DHCP Server. C) Mobile Router: Mobile router, which doesn’t need any wireless links, one of its biggest advantages is that it can work with virtually any type of interface. It can be used Fast Ethernet and Ethernet connection.
6) DIFFERENT TYPES OF TRANSMISSION MEDIUM: I. Unguided Media II. Guided Media I. Unguided Media: A. Microwave System: Microwave System transmits voice and data through the atmosphere as high frequency radio waves. However at microwave frequencies, the electromagnetic waves cannot bend or pass obstacles like hill. Thus it is necessary to be in a line of sight. B. Satellites: Satellite system is basically a microwave relay station placed in orbit around the earth. These satellites are launched by either rockets or space shuttle. Traditionally the orbit has been 22300 miles above the earth. Solar Cells Concentrated Beam Antenna Transmission Antenna Control Antenna
Fig: Satellite Advantages: It can be used for data transmission between any two randomly chosen points in an area. The costs are independent of the distance A satellite having many transponders has enormous data communication capability. Disadvantages: The initial cost is very high. Special security measures are needed to prevent unauthorized tampering of information. II. Guided Media: A) Twisted Pair Cable: A twisted pair cable consists of two bunches of thin copper wires, each bunch enclosed separately in a plastic insulation, then twisted around each other to reduce information by adjacent wires. These cables are commonly used in local telephone communication and short distance digital data transmission. Fig: Twisted Pair Cable B) Coaxial Cable: Coaxial cable consists of conducting core, insulating material, a secondconducting sheath. This is able to transmit data at high rates. The signal is transmitted bythe inner copper wire and is electrically shielded by the outer metal sleeve. They areextensively used in long distance telephone lines as cables for cable TV. Insulator
Plastic Cover Outer Conductor Inner Conductor Fig: Coaxial Cable C) Optical Fibers: Optic fiber is a thin thread of glass or other transparent material to carry lightbeams or transmits pulsating beams of light. Light travels much faster than electricity. Itcan transmit data at much higher speed than copper wires or coaxial cables and also withno significant loss of intensity over very long distance. Sender Receiver Cladding Fig: Optical Fiber Advantages: Very high bandwidth Protection against electromagnetic interference More secured as they can not be tapped easily Light weight and no corrosion Disadvantages: It is difficult to align and join two fiber optic They can not have sharp beams. 7) DATA TRANSMISSION MODE: There are three ways or modes of transmitting data from one point to another. They are: I) Simplex; II) Half duplex; III) Full duplex.
I. Simplex: If transmission is simplex, communication can take place in only one direction. Devices connected to such a circuit are either a send only or receive only device. One direction only Sender Receiver II. Half Duplex: A half duplex system can transmit data in both directions, but only in one direction at a time. Half duplex line can alternately send and receive data. This is the most common type of transmission for voice communication because only one person is supposed to speak at a time. Receiver -------- Sender ------------------------------ In both direction but not at the same time III. Full Duplex: Full duplex system allows information to flow simultaneously in both directions in the transmission path. Use of a full duplex line improves efficiency, because the line turn around time required in a half duplex arrangement is eliminated. Receiver -------- Sender Both directions at the same time8) ASYNCHRONOUS & SYNCHRONOUS TRANSMISSION: Data transmission on a communication line is normally carried out in two different modes - asynchronous and synchronous. Asynchronous Transmission: Here data is sent one byte at a time. Each string of bits making up the byte is bracketed or marked off, with special control bits. That is a Start bit represents the beginning of a character and stop bit represents its end. It is well suited to many keyboard type terminals. The advantage of this method is that it does not require any local storage at the terminal o the computer. 0 Character 0 1 0 Character 1 1 Receiver Sender
Fig: Asynchronous Transmission Synchronous Transmission: Synchronous using start and stops bits to send data in blocks. Start and stop bits pattern called Sync bytes, are transmitted at the beginning and the end of the blocks. The number of characters in a block may be variable, and may consist of hundreds of characters. It is well suited to remote communication between computer and such devices as buffered terminals and printers. Start Sync Characte Characte Error Stop Receiver Bytes r r Check Sync Sender Bytes bytes Fig: Synchronous Transmission9) DIFFERENT TYPES OF SWITCHING TECHNIQUES: I. Packet Switching: A packet is a maximum-fixed-length block of data for transmission. The packet also contains instructions about its destination. Electronic message are divided into packets for transmission over a Wide Area Network (WAN) to their destination, through the most expedient routes is packet switching. Advantages: Handle high volume traffic in a network. Sending message over long distance. Packets are of small and fixed size.
The method is fast enough for interactive / real time applications Uses: Telnet Data sending Tymnet AT & T’s Accunet. II. Circuit Switching: Circuit switching by which the transmitter has full use of the circuit until the data has been transmitted and the circuit is transmitted. Advantages: Once the circuit is established, data is transmitted with no delay other than the propagation delay, which is negligible. It is suitable for low-speed communication between a terminal and a computer, because the method is simple and requires no special facilities. The method is suitable for long continuous transmissions. Uses: Telephone Company Voice Networks Data and Real-time voice and video.10) MULTIPLEXING: Multiplexing is the transmission of multiple signals over a single communication line or channel. That is, it is the method of dividing a physical channel into multiple logical channels to enable a number of independent signals to be simultaneously transmitted. 3 devices of multiplexing are:
i. Multiplexers: Multiplexers is a device that manages several low speed transmissions into high speed transmission. A multiplexer takes several data communication line or signals, and converts them into one data communication line or signal at the sending location. ii. Concentrators: It is a piece of hardware that enables several devices to share a single communication line. The advantage of using a concentrator is that devices of varying speeds and types are connected to the concentrator, which in turn is connected to the host computer by high- speed lines. iii. Front-End Processor: It is a smaller computer that is connected to a large computer and assists with communication functions. First High speed line Second Multiplexer Multiplexer Mainframe Work stations Fig: Multiplexing11) NETWORK TOPOLOGIES: The physical layout or shape of a network is called network topology. It determines the data paths, which may be used between any pair of nodes in the network. The four major topologies are star topology, bus topology, ring topology and hybrid topology.
Star Topology: Star topology is a star network. All computers and other communication devices are connected to a control hub such as a file server or host computer, which centrally controls communication between any two other computers by establishing a logical path between them. The main advantage is if any of the local computers fails, the remaining portion of the network is unaffected. Advantages Easy to setup One cable can not crash network Disadvantages One hub crashing downs entire network Uses lots of cable Fig: A star topology. Ring Topology: Ring topology is a ring network where all computers and other communications devices are connected in a communication loop. Electronic message are passed around the ring in one direction. The only decision a node ahs to take is whether the data is for its own use. If it is addressed to it, it utilizes it. Otherwise, it merely passes it on to the next node. Advantages Time to send data is known No data collisions Disadvantages Slow Lots of cable
C E A B P C D Bus Topology: In a bus network all communication devices are connected to a common cable called a bus. Bus line Advantages: a) It helps in reducing the number of physical lines. b) The failure of a computer does not affect the communication. c) Addition of new computers to the network is easy. Disadvantages: a) All computers in the network must have good communication and decision making capability. b) If the communication line fails, the entire system breaks down. Hybrid Topology: Hybrid topology is a combination of two or more different network topologies. The exact configuration of the network depends on the needs and the overall organization structure of the company involved. R ou t e r
Fig: Hybrid Topology Mesh Topology: Another kind of topology is Mesh topology. A network configuration in which each device has a dedicated point to point link to every other device. Advantage Data will always be delivered. Disadvantages Lots of cable. Hard to setup. Fig: Mesh Topology
12) DEFINITION OF OSI MODEL & ITS DIFFERENT LAYERS: Open System Interconnection or OSI is a set of protocols that allows any two different systems to communicate regardless of their underlying architecture without changing hardware and software. There are seven layers involving with OSI Model. 7. Application Layer 6. Presentation Layer 5. Session Layer 4. Transport Layer 3. Network Layer 2. Data Link Layer 1. Physical Layer I. Physical Layer: Physical Layer is responsible for movements of individual bits from one hop to next. It also performs: Representation of bit; Data rate; Synchronization of bit; Line configuration; Physical topology; Transmission mode.
II. Data Link Layer: Data link layer to organize bits into frames and provide hop to hop delivery. It performs the following operations: Framing of bits; Physical addressing; Flow controlling; Error controlling; Access controlling. III. Network Layer: Network layer to move packets from source to destination and providing internetworking. Logical address generating; Routing. IV. Transport Layer: Transport layer to provide reliable process of message delivery and error recovery. It also performs: Service point addressing; Connection control; Flow and error control. V. Session Layer: Session layer to establish manage and terminate session. It accomplish the following job: Dialog control; Synchronization. VI. Presentation Layer: it is responsible for translation, compression and encryption. VII. Application Layer: Application Layer to allow access to network resources that responsible for providing services to the user. File transfer access and management Mail services; Directory services.13) DEFINITION & COMPONENTS OF INFORMATION SYSTEM:
Information is the data placed in meaningful and useful context for an end user. Information obtained by processing data into meaningful and useful context and form. Information System is an organized set of components for collecting, transmitting, storing and processing data in order to deliver information. Data Processing Information Fig Information System $35000 12 units Sales Persons: J. Jones $10000 15 units Processing Data States Territory: Western Region J. Jones Current Sale: 37 unit= $60000 Western Region Components of information System: End User and IS specialized Data and knowledge base Software Programs and procedure Hardware Machines and Media Communication and Network Support14) CLASSIFICATION OF INFORMATION SYSTEM: Transactions Processing System Operations Supports System Process Control System Office Automation System
Information System Management Information System Management Support System Decision Support System Executive Information System15) LAN, MAN & WAN: LAN: A Local Area Network is usually privately owned and links the devices in a single office, building or campus. Depending on the needs of an organization and the type of technology used, a LAN can be as simple as two PCs and a printer in someone’s home office or it can extend throughout a company and include audio and video peripherals. Currently LAN size is limited to a few kilometers. HUB C C C C C C C C C C C C Fig: An isolated LAN connecting 12 computers to a HUB in a closet
LAN is designed to allow resources to be shared between personal computers and workstations. The resources to be shared can include hardware, software or data. WAN: A Wide Area Network (WAN) provides long distance transmission of data, image, audio and video information over large geographic areas that may comprise a country, a continent or even the whole world. We normally refer to the first as a switched WAN and to the second as a point to point WAN. The switched WAN connects the end systems, which usually comprise a router. The point to point WAN is normally a WAN leased from a telephone or cable TV provider that connects a home computer or a small LAN to an Internet Service Provider. MAN: A Metropolitan Area Network (MAN) is a network with a size between a LAN and a WAN. It normally covers the area inside a town or a city. It is designed for customers who need high speed connectivity, normally to the internet and have end points spread over a city or part of a city.16) Definition of Network Address, Internet Protocol & IP Address : Network Address: Network Address refers to the designation used in routing to send packets to a remote network. Ex: 172.16.0.0 Internet Protocol: Internet Protocol is a set of standard communications and routing mechanisms that allow network users to upload files send e-mail and download WebPages. IP Address: IP Address is a numeric identifier assigned to each machine on an IP network. An IP address is software address not hardware address. The Network ID identifies the TCP/IP hosts that are located on the same physical network. All hosts on the same physical network must be assigned the same network ID to communicate with each other. 32 bits Network ID Host ID The Host ID identifies a host within a network. The Network ID is the software ID.
Range of ClassNetwork ID0 – 127 A 0128 – 191 B 10192 – 223 C 110224 – 239 D 1110240 - 255 E 1111 32 Bits 8 Bits 8 Bits 8 Bits 8 Bits Network ID Host ID Host ID Host ID Network ID Network ID Host ID Host ID Network ID Network ID Network ID Host ID Multicast Address Reserve For Future Use 17) Definition of E-Commerce & Its Advantages: The face of doing business both within our country and overseas is rapidly changing. The internet, Electronic Funds Transfer (EFT), e-commerce and the like have brought with them both opportunities and threats.
Business competitors may no longer just the business down the street, butrather a business located in any number of places around the world. The flip side ofcourse is that the potential market is now not just in local area but cashed upconsumers across the world. E-commerce won’t go away. Online and internet commerce is currentlyexperiencing dramatic growth. According to experienced organizations, theintroduction of e-commerce can potentially: Lower transaction cost; Reduce inventory holdings; Provide a competitive business advantages; Expand one’s market; Increase speed to market; Streamline supply chain management.E-commerce includes electronic trading, electronic messaging, Electronic DataInterchange (EDI), Electronic Mail, electronic catalogues, internet, intranet andextranet services.Additional e-commerce resources: Test to find out if your business is e-commerce ready. Access a copy of the government’s e-commerce guide. This will provide the e-business information and resources. Common type of e-commerce that one’s business may engage. The four webolution steps 10 safe online shopping tips.18) Definition of Contracts & Its Basics Contracts: Law of Contracts; Issues for e-commerce.
Basics of Contract: o Offer; o Acceptance; o Intentions to enter legal relations; o Consideration; o Legal Capacity; o Genuine Consent. Offer: Clear statement of terms; Person who makes it prepared to be bound; Not just an invitation to treat. Acceptance: Unqualified agreement to terms of offer; Express or inferred by conduct; Can’t be forced on unwilling person. Time of creation of contract Contract formed at time and place the acceptance is communicated to offeror. Termination or Revocation of contract Can be revoked prior to acceptance; Revocation must be communicated to offeror. Certainty Essential parts of contract must be clear and complete; Courts may imply a meaning; Uncertain term can be “severed”. Consideration Valuable Consideration;
Passing between parties to contract; Can’t be unlawful or immoral. Intention Express; Inferred from the circumstances; Must be genuine consent – not obtained under duress. Capacity Age; Intellectual capacity. Terms & Conditions Express; Implied. Formalities Oral or written; Writing required under statute, for example – sale of land.19) Practical Concerns For E-commerce Deals Identity and capacity of seller or buyer; Authenticity of offer and acceptance; When and where contract formed; Governing Law; Terms and Conditions; Agreement on electronic payment system; Security of information exchanges; Consequences on breach; Storing electronic data to prevent alteration.20) Electronic Transactions Act
I. Electronic Transactions Act Federal law with mirror state laws (NSW, VIC, WA); To remove obstacles to electronic transactions, communications, signatures and record keeping; 1 July 2001 applies to all federal laws unless exempted.II. Electronic Transactions Act Validates electronic transactions; Given in writing met electrically now Government can specify technology requirements Business requirement valid only with consent Signature – parties free to agree on method; Production and retention of documents; o Method must ensure integrity and accessibility. Time and place of dispatch and receipt of communication.III. Electronic Transactions Act Time of dispatch is when it enters the first information system outside control of sender; Time or receipt is when it enters an information system designated by the addressee for receiving it; Place of dispatch and receipt taken to be respective places of business.IV. Electronic Transactions Act Record keeping OK electronically if law says o Information to be recorded in writing; o A written document to be kept; o An electronic communication to be kept. Record must be kept identifying origin, destination, and time of sending and receipt of electronic communication.
21) Making of A Contract • What terms do you want to include? • What risks are you trying to avoid? • How will disputes about contract be dealt with? • What is the Governing Law? • Who will sign it?22) Setting Up A Business Entity • Sole Trader • Partnership • Company • Trust A. Sole Trader All profits All losses All liabilities Own name or choose separate business name Register business name B. Partnership Basics Carrying on a business; With a view to profit. Established by written agreement, oral agreement or conduct. Law Partnership Act 1892 (NSW); Corporations Law: Not more than 20 partners (except doctors, solicitors and accountants).
Features: Profit Sharing; Joint and several liability; Fiduciary duties to partners. C. Companies Law Corporations Act; Artificially legal entity; Liability of a member can be limited. Features: Constitution; Directors Duties; Limits on raising money from the public. A Company Can Form By: Registering name; Lodge application with ASIC; Registered office; Names of directors and members.23) Choosing of the Structure • Where is an entrepreneur getting his money from? • What kind of risk involved? • Who will be in control? • What are the ongoing costs?
24) Definition of Domain Name: Human friendly form of an Internet address. Actual address is an Internet Protocol (IP) number System globally administered by ICANN Generic top level domains (gTLDs) .com, .org, .net, .edu, .gov, .biz Country code top level domains (ccTLDs)25) Domain Name Registration in Australia: Open and closed domains Open - .com, .org, .net, .info, .biz Closed - .gov, .edu, .mil auDA administers .com. au space To register in.au space must be commercial entity registered and trading in Australia. Licensed on a first come first serve basis Domain names never meant to confer property rights Clash with trade marks auDA has a dispute resolution scheme which applies to all domain names registered or renewed from 1 August 2002. ICANN has the UDRP for .com etc domains.26) Domain Names & Other Business Identifiers: Trade Marks Personality Rights Place names
Tension with domain names o Reverse domain name hijacking o Cybersquatting