ITD1011- Introduction to IT جـامعـــة الـجــزيــرة UNIVERSITY OF JAZEERA Dr. Mohamed Sammouda
Objectives • Define the term telecommunications and identify and describe the function of the components of a telecommunications system. • Identify and briefly describe three basic data processing strategies, including their advantages and disadvantages. • Briefly describe how the Internet works, including alternatives for connecting to it and the role of Internet service providers. • Identify and briefly describe common Internet services. • Describe the World Wide Web and the way it works, including the use of Web browsers, search engines, Java, and other Web tools. • Define the terms intranet and extranet and discuss how organizations are using them. • Identify several control and management issues associated with the use of networks.
Elements of a Telecommunications System • Telecommunications refers to the electronic transmission of signals for communications, and it has the potential to create profound changes in business because it lessens the barriers of time and distance. • Telecommunication medium: anything that carries an electronic signal and interfaces between a sending device and a receiving device. • Telecommunications technology enables business people to communicate with co-workers and clients from remote locations. • Telecommunications can help businesses solve problems and maximize opportunities.
Elements of a Telecommunications System • Transmission media • Various types of communications media are available. Each type exhibits its own characteristics, including cost, capacity, and speed. • In developing a telecommunications system, the selection of media depends on the purpose of the overall information and organizational systems, the purpose of the telecommunications subsystems, and the characteristics of the media.
Common Wiring and Cabling Types (a) Twister-pair wire (b) Coaxial cable (c) Fiber-optic cable
Carriers and Services • Common carriers: Telecommunications carries is a long-distance telephone companies that provide the telephone lines, satellites, modems, and other communication technology used to transmit data from one location to another. • Switched lines: a standard communication line that uses switching equipment to allow one transmission device to be connected to other transmission devices. • Digital subscriber lines (DSL): a communications line that uses existing phone wires going into today’s homes and businesses to provide transmission speeds exceeding 500 Kbps at a low costs (20$ or more by month). (this speed means faster Internet access and downloads compared with standard phone line. DSL is not available every where.
Costs, Advantages, and Disadvantages of Several Line and Service Types
Networks and Distributed Processing • Computer network - communications media, devices, and software needed to connect two or more computer systems. • When an organization uses two or more computer systems, it can follow one of three basic data processing strategies: • 1- Centralized processing - processing occurs in a single location or facility, providing a highest degree of control. Useful for financial institutions that require a high degree of security. • 2- Decentralized processing - processing devices are placed at various locations, so individual computer systems are isolated and do not communicate with each other. Suited for companies that have independent operating divisions.
Networks and Distributed Processing • 3- Distributed processing - computers are placed at remote locations but are connected to each other via telecommunications devices. Using this method allows all the locations to share data and programs. • Distribution of processing across the organization ensures that the right information is delivered to the right individuals, maximizing the capabilities of the overall information system by balancing the effectiveness and efficiency of each individual computer system.
Network types: A Typical LAN • Local Area Network (LAN)is a network that connects computer systems and devices within the same geographic area. • LANs are wired into office buildings and factories.
A Wide Area Network • Wide Area Networkis a network that ties together large geographic regions using microwave and satellite transmission or telephone lines. • When you make a long-distance phone call, you are using WAN. • Networks that link systems between countries are called international networks.
Communications Software and Protocols • Communications Software - provides a number of important functions in a network. (Error checking and message formatting). In case of problem, the software can indicate what is wrong and suggest possible solutions. • Network Operating System (NOS)- a system software that controls the computer systems and devices on a network and allows them to communicate with each other. • (NOS performs the same types of functions for the network as operating system software does for a computer.
Communications Software and Protocols • Network management software - a manager can monitor the use of individual computers and shared hardware (such as printers), scan for viruses, and ensure compliance with software licenses. • Communications protocol - rules and standards that make communications possible. • A number of communications protocols are used by companies and organizations of all sizes.
How the Internet Works • Internet Protocol (IP): a communication standard that enable traffic to be routed from one network to another as needed. A set of conventions used to pass packets from one host to another. • Transport Control Protocol: a protocol that includes rules that computers on a network use to establish and break connections. • Uniform Resource Locator (URL): an assigned address on the Internet for each computer.
U.S. Top-Level Domain Affiliations www.sony.com (www: host name) (sony: Domain Name) (com: Top-level Domain)
Accessing the Internet There are three ways to connect to the Internet. Which method is chosen is determined by the size and capability of the organization or individual. 1- Connect via SLIP/PPP: This approach requires a modem and the TCP/IP protocol software plus Serial Line Internet Protocol (SLIP) or Point-to-Point Protocol (PPP) software. SLIP and PPP are two communications protocols that transmit packet over telephone lines, allowing dial-up access to the Internet. 2- Connect via an On-Line Service: This approach requires a modem, standard communications software, and an On-line information service account. There is normally a fixed monthly cost for a basic services including e-mail.
Accessing the Internet 3- Connect via Internet Service Providers (ISP), is any company that provides individuals and organizations with access to the Internet. To use this type of connection, you must have an account with the service provider and software that allows a direct link via TCP/IP.
Two Approaches to Electronic Data Interchange • Electronic Data Interchange (EDI): an inter-company, application-to-application communication of data in standard format, permitting the recipient to perform the functions of a standard business transaction. • Some companies will do business only with suppliers and vendors using compatible EDI systems.
The World Wide Web WWW: An Internet service comprising tens of thousands of independently owned computers that work together as one. • Home page: a cover page for a Web site that has titles, graphics, and text. • Hypermedia: tools that connect the data on Web pages, allowing users to access topics in whatever order the wish. • Hypertext markup language (HTML): the standard page description language for Web pages.
Intranets and Extranets • Intranet – an internal corporate network built using Internet and WWW standards and products • Extranet- a network that links selected resources of the intranet of a company with its customers, suppliers, or other business partners • Virtual private network - a secure connection between two points across the Internet • Firewall - a device that sits between your internal network and the outside Internet
Privacy and Security • Cookie: a text file that an Internet company can place on the hard disk of a computer system to track the web movements of its users. • Cryptography: The process of converting a message into a secret code and changing the encoded message back to regular text. • Encryption: The conversion of a message into a secret code. • Digital Signature: an encryption technique used to verify the identity of a message sender for the processing of on-line financial transactions.
Summary • Networks - used to share hardware, programs, and databases across the organization. • Internet - transmits data from one computer (called a host) to another. • The Web - a collection of tens of thousands of independently owned computers that work together as one in an Internet service.