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    Itm 4 Itm 4 Document Transcript

    • Module 4Business Value of Telecommunication NetworksTwo companies-no geographic boundariesConnecting computers……………Businesses have become Networked Enterprises  Network means an interconnected or interrelated chain, group or systemNetworked Enterprises  Better business communication  Better distribution of data  Instant transactions  Flexible work force  Greater efficiencyEmergence of Digital Firm • Digitally enabled relationships with customers, suppliers, and employees • Core business processes accomplished using digital networks • Seamless flow of information within the firm, and with strategic partners
    • Components of an information system  People resources-People are required for the operation of all information systems  End users- are people who use an information system or the information it produces.  IS specialists –are people who develop and operate information systems
    •  System analysts-design information systems based on the information requirements of end users.  System developers-create computer programs based on the specifications of systems analysts.  System operators-monitor and operate large computer systems and networksHardware resources-include all physical devices and materials used in information processing.  Machines-physical devices (computers, peripherals, telecommunications networks, etc.)  Computer system –which consist of central processing units containing microprocessors, and a variety of interconnected peripheral devices  Computer peripherals-which are devices such as a keyboard or electronic mouse for input of data and commands, a video screen or printer for output of information, and magnetic or optical disks for storage of data resources.Software resources-include all sets of information processing instructions  System software-such as an operating system program, that controls and supports the operations of a computer system.  Application software-are programs that direct processing for a particular use of computers by end users.  Data resources-Data constitutes a valuable organizational resource  Databases - a collection of logically related records or files. A database consolidates many records previously stored in separate files so that a common pool of data records serves many applications.  Knowledge Bases - which hold knowledge in a variety of forms such as facts and rules of inference about various subjects.Network resources-  Telecommunications networks like the Internet, intranets, and extranets have become essential to the successful electronic business and commerce operations of all types of organizations and their computer-based information systems . Network resources include:  Communications media (twisted-pair wire, coaxial cable, fiber-optic cable, and microwave, and satellite wireless systems.  Network support (people, hardware, software, and data resources that directly support the operation and use of a communications network)  TELECOMMUNICATIONS NETWORK MODEL
    • Terminals  Terminals are any input/output devices that use telecommunications networks to transmit or receive data.1. Video Terminals2. Microcomputers3. Telephones4. Office Equipment5. Transaction Terminals  Telecommunications Processors Support data transmission and reception between terminals and computers.
    • They include:1. Modems2. Switches 3. Routers - Convert digital to analog, control the speed ,accuracy and efficiency of the communication flow. Modems:  These devices are the most common type of communications processor, and are probably the most widely used data communications hardware in business. Functions of modems include:  Convert digital computer signals to analog signals for transmission over telephone lines, then to receive these signals and convert them back to digital signals. This process is known as modulation and demodulation. The word "modem" is a contraction of modulate and demodulate.  Switch - is a communications processor that makes connections between telecommunications circuits in a network so a telecommunications message can reach its intended destination.  Router - is a communications processor that interconnects networks based on different rules or protocols, so a telecommunications message can be routed to its destination.  Hub - is a post switching communications processor. This allows for the sharing of the network resources such as servers, LAN workstations, printers, etc. Telecommunications Channels • Telecommunications channels are the part of a telecommunications network that connects the message source with the message receiver. • They include the physical equipment used to connect one location to another for the purpose of transmitting and receiving information. • Data are transmitted and received over channels, which use a variety of telecommunications media. Media include: 1. Twisted-pair Wire 2. Coaxial Cables 3. Fiber Optic Cables 4. Microwave Systems
    • 5. Communications SatellitesTwisted-Pair Wire Twisted-pair is ordinary telephone wire, consisting of copper wire twisted into pairs (twisted pair wire). Most widely used media for telecommunications. Used in established communications throughout the world. Used for both voice and data transmissions. Used extensively in home and office telephone systems and many LANs and WANs.Disadvantages: Susceptible to a variety of types of electrical interference (noise), which limits the practical distances Signals must be “refreshed” every one to two miles through the use of repeaters, which are very expensive.Coaxial Cable Consists of copper or aluminium wire wrapped with spacers to insulate and protect it. Insulation minimizes interference and distortion of the signals the cable carries. Can carry a large volume of data - about 100 million bits per second (1800 to 3600 voice calls at once). A 2" diameter coaxial cable can carry up to 5,500 channels. Coaxial cables can be bundled together into a much larger cable for ease of installation. Can be placed underground and laid on the floors of lakes and oceans. Allows for high-speed data transmission used in high-service metropolitan areas for cable TV systems Used extensively in office buildings and other work sites for local area networks. Disadvantages: More expensive than twisted pair.Fiber optics
    •  This media consists of one or more hair-thin filaments of glass fiber wrapped in a protective jacket. Signals are converted to light form and fired by laser in bursts. Relatively low cost Offers high transmission volume. A 2" diameter fiber optic cable can carry up to 50,000 channels. Provides substantial size and weight reductions. Provides increased speed and greater carrying capacity than coaxial cable and twisted-pair lines. Is not susceptible to electronic noise and so has much lower error rates than twisted-pair and coaxial cable. Message security of fiber optic communications is very resistant to illegal data theft; taps can be easily detected.TYPES OF TELECOMMUNICATIONS NETWORKSLocal Area Networks(LAN) Metropolitan Area Networks(MAN) Wide Area Networks(WAN) Virtual Private Networks(VPN) Client/server networksLocal Area Network (LAN)
    •  Are telecommunications networks that connect information-processing devices within a limited physical area. These networks cover areas such as: · Offices · Classrooms · Buildings · Manufacturing plantCharacteristics of LANs:• LANs use a variety of telecommunications media, such as ordinary telephone wiring, coaxial cable, or wireless radio systems to interconnect microcomputer workstations and computer peripherals.• To communicate over the network, a PC usually has a circuit board called a network interface card.• Most LANs use a powerful microcomputer with a large disk capacity as a file server or network server that contains a network operating system program (e.g., Novell NetWare) that controls telecommunications and the use of network resources.• LANs allow end users in a workgroup to communicate electronically; share hardware, software, and data resources; and pool their efforts when working on group projects.Metropolitan Area Networks(MAN) Links multiple LANs with in a large city Covers a distance of 50kmsWide Area Network (WAN) are telecommunications networks that cover large geographic areas. These networks cover areas such as: · Large city or metropolitan area · Whole country · Many countries and continents Ex: used by many MNCs to transmit and receive information among their stake holders
    • Virtual Private Network(VPN)• Establish secure Intranets and extranets• is a secure network that uses the Internet as its main backbone network, but relies on the firewalls and other security features of the Internet and Intranet connections and those of participating organizationsClient/Server NetworksCharacteristics of a client/server network: End user PC or NC workstations are the clients. Clients are interconnected by local area networks and share application processing with network servers, which also manage the networks.• Downsizing of larger computer systems by replacing them with client/server networks. For example, a client/server network of several interconnected local area networks may replace a large mainframe-based network with many end user terminals.Network Topology is the layout pattern of interconnections of the various elements of a computer Network topologies may be physical or logical. Physical topology refers to the physical design of a network including the devices, location and cable installation. Logical topology refers to how data is actually transferred in a networkThree basic topologies used in wide area and local area telecommunications networks are the: Star network Ring network Bus network
    • Advantages of the star network:  Several users can use the central unit at the same time  Easy to detect faults and to remove parts.  No disruptions to the network when connecting or removing devices.  Benefits from centralization: As the central hub is the bottleneck, increasing its capacity, or connecting additional devices to it, increases the size of the network very easily. Centralization also allows the inspection of traffic through the network. This facilitates analysis of the traffic and detection of suspicious behavior. Disadvantages of the star network:  The whole network is affected if the main unit “goes down,” and all communications stop.  Considered less reliable than a ring network, since the other computers in the star are heavily dependent on the central host computer. If it fails, there is no backup processing and communications capability and the local computers will be cut off from the corporate headquarters and from each other.  Cost of cabling the central system and the points of the star together are very high.
    • Advantages: Ring networks do not require a central computer to control activity nor does it need a file server. Each computer connected to the network can communicate directly with the other computers in the network by using the common communications channels, and each computer does its own independent applications processing. When one computer needs data from another computer, the data is passed along the ring. The ring network is not as susceptible to breakdowns as the star network, because when one computer in the ring fails, it does not necessarily affect the processing or communications capabilities of the other computers in the ring. Performs better than a bus topology under heavy network loadDisadvantages: One malfunctioning workstation can create problems for the entire network Moves, adds and changes of devices can affect the network Communication delay is directly proportional to number of nodes in the network Bandwidth is shared on all links between devices
    • Advantages: Easy to implement and extend. Well-suited for temporary or small networks not requiring high speeds (quick setup), resulting in faster networks. less expensive than other topologies Cost effective; only a single cable is used. Easy identification of cable faults.Disadvantages: Limited cable length and number of stations. If there is a problem with the cable, the entire network breaks down. Performance degrades as additional computers are added or on heavy traffic (shared bandwidth). It works best with limited number of nodes. Commonly has a slower data transfer rate than other topologies.
    • InternetDefinition  A network made up of millions of smaller private networks each with the ability to operate independent of, or in harmony with, all the other millions of networks connected to the InternetNetwork of network is a group of two or more networks that are,  Interconnected physically  Capable of communicating and sharing data with each other  Able to connect together as a single network
    •  At the end of December, 121 million Indians will be accessing the Internet at least once a week to check emails, chat or log on to a social network  India is adding Internet users at the rate of almost 5-7 million a month  Internet is changing the business landscape forever in favour of India. "Now startups look to India when planning to start a business... earlier they would flock to the US,“  About 2 billion people worldwide access the Internet and 25% of them are from China. India contributes about 6% to the worlds Net population and the US 12.5%Cheapest and fastest means to get, provide and compile information  Getting Information-World wide Web  Providing Information- Publishing, Blogging and teaching  Compiling- conduct surveysInternet Working-  Modem- enables two computers to communicate through phone lines  Computer  Software- Communication software & client software
    •  Browser softwareInternet Access-  Dialing ISPs – users Modems are connected to ISPs modem  Direct connection to an ISPInternet Addressing-  IP address is an identifier for a particular machine on a particular network  Scheme to identify computers on the internet.  IP address consists of 4 sections representing the machine, host and the network the host belongs to.Domain Name-  Way to identify and locate computers connected to the internet  Contains two or more components separated by periods (dots)  Last portion of the name describes the type of organizationEg: .biz-business, .com-commercial entities etc
    • E-Learning  E-Learning is using the Internet to enable learning (eliminates time and distance barriers).  Include:  Computer-based training.  Distance learning.  Online learning.  On-demand learning.Logs and Blogs  Online journals that link together into a large network of information sharing.  Blogs discuss topics from poetry to political opinions.  Can take on different forms:
    •  Moblogging  Vlogging  Make every individual a virtual publisher.E-Tutoring  Fluent in any subject  Tutoring experience-online tutoringBusiness Use of the Internet  Collaboration among business partners  Providing customer and vendor support  Electronic commerce
    •  Marketing and sales  Customer relationship management applications  Cross-functional business applications  Applications in engineering, manufacturing, human resources, and accounting  Enterprise communications and collaboration  Strategic business alliances  Substantial cost savings can arise because applications that use the Internet and Internet- based technologies  Attracting new customers with innovative marketing and product offerings.  Retaining present customers with improved customer service and support.  Generating revenue through electronic commerce applications.Doing Business over InternetEvolution of E-Business  Now, the term e-business refers to business conducted over the Internet  EDI (Electronic Data Interchange) is one of the oldest forms of e-business  EDI is the direct computer to computer transfer of business information, using a standard format.  Software programs on different systems can exchange information without human intervention.  Quote requests, order forms, etc.  With the growth of the Internet more businesses are using it to transact business between partners-B2B, B2C, B2E  India to be ranked 3rd largest Internet market after China and the US
    • Six major business values by doing business on WWW–  Generate new revenue from online sales.  Reduce costs through online sales and customer support.  Attract new customers via Web marketing and advertising and online sales.  Increase the loyalty of existing customers via improved Web customer service and support.  Develop new web-based markets and distribution channels for existing products.IntranetA network inside an organization that uses Internet technologies to provide an Internet-likeenvironment within the enterprise for information sharing, communications, collaboration, and thesupport of business processesThe first intranet websites and home pages began to appear in organizations in 1996-1997  An intranet is protected by security measures such as passwords, encryption, and fire walls, and thus can only be accessed by authorized users through the Internet.  A company’s intranet can also be accessed through the intranets of customers, suppliers, and other business partners via extranet links.
    •  Since intranets are Internet-like networks within organizations, they depend on all of the information technologies that make the Internet possibleCommunications and Collaboration  Intranets can significantly improve communications and collaboration within an enterprise.Examples include:  Using an intranet browser and PC or NC workstation to send and receive E-mail, voicemail, paging, and faxes to communicate with others within your organization, and externally through the Internet and extranets.  intranet groupware features improves team and project collaboration with services such as discussion groups, chat rooms, and audio and videoconferencing.Web Publishing:  ease, attractiveness, and lower cost of publishing and accessing business information internally via intranet websites has been one of the primary reasons for the explosive growth in the use of intranets in business.Examples include:  Company newsletters, technical drawings, and product catalogs can be published in a variety of ways including Web pages, E-mailBusiness Operations and Management:  Employees within the company, or external business partners can access and run such applications using Web browsers from anywhere on the network whenever needed. Examples include:  Many companies are developing customer applications like order processing, inventory control, sales management, and executive information systems that can be implemented on intranets, extranets, and the Internet.
    • Extranet  Network links that use Internet technologies to interconnect the intranet of a business with the intranets of its customers, suppliers, or other business partnersCompanies can:  Establish direct private network links between themselves, or create private secure Internet links between them called virtual private networks.  Use the unsecured Internet as the extranet link between its intranet ,consumers and others, but rely on encryption of sensitive data and its own firewall systems to provide adequate security.
    • Business Value of Extranets:The business value of extranets is derived from several factors: The Web browser technology of extranets makes customer and supplier access of intranetresources a lot easier and faster Extranets enable a company to offer new kinds of interactive Web-enabled services to theirbusiness partners. Thus, extranets are another way that a business can build and strengthen strategicrelationships with its customers and suppliers. Extranets enable and improve collaboration by a business with its customers and otherbusiness partners. Extranets facilitate an online, interactive product development, marketing, and customer-focused process that can bring better designed products to market faster.