Internet & Communications Technology SECTION 4 APPLICATIONS & IMPLICATIONS OF INFORMATION TECHNOLOGY & COMMUNICATIONS TECHNOLOGY Internet & Communications Technology

Internet & Communications Technology On completing Section 4, you should be able to: Use terms associated with data communications & networks Distinguish among Internet, Intranet & Extranet Explain concepts associated with the internet Describe measures to secure data & maintain data integrity

Internet & Communications Technology Today’s class will cover the following objectives: Use terms associated with data communications & networks Distinguish among Internet, Intranet & Extranet

Internet & Communications Technology Definitions: Data Communication: Transmission of data from one location to another to enable interaction between locations. Network: Group of computers & peripheral devices that are connected to each other by cables or wireless electronics. Bandwidth: Volume of data that can be transmitted through the channel each second

Internet & Communications Technology Definitions: (continued) Modem (Modulator/Demodulator) Device that converts digital signals into analog signals and vice versa. It is measured in bits per second (bps). Upload Process by which the host computer sends a file to a remote computer via communication channels Download Process by which a host computer obtains a file from a remote computer via communication channels.

Internet & Communications Technology Definitions: (continued) Point-to-Point transmission Process by which data is sent from one location to another. Broadcast transmission Process by which data is transmitted in such a way that any person with the proper equipment can receive it. With this transmission, it is difficult to control who receives the data. Hotspot Any location where network access (usually Internet access) is publicly available.

Internet & Communications Technology Definitions: (continued) Protocol Set of rules and procedures controlling the transmission and receipt of data so that different devices can communicate with each other File Server Computer with large storage capacity that is used to store and manage files which are used by other computers on the network.

Internet & Communications Technology Data Communication There are 3 categories of data communication channels: Narrowband: Data is transmitted at a slow speed (just over 10 characters/second), e.g., telegraphed transmission Voiceband: Data is transmitted at rates of up to 8000 characters/second via telephone lines. Broadband: Data is transmitted very quickly (hundreds of thousands of characters/second) via the use of fibre-optic cables, microwave and satellite transmissions.

Internet & Communications Technology Types of Communication Modes Simplex: Data is transmitted in only one direction Half Duplex: Data can be transmitted in both directions, but not at the same time. Duplex or Full-Duplex: Communication is allowed in both directions and it can occur simultaneously. What are examples of each type?

Internet & Communications Technology Networks There are 3 types of networks that we will look at: Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN)

Internet & Communications Technology Local Area Networks (LANs) Two or more computers connected to each other within the same geographical area (not necessarily in the same building – home, office, small group of buildings (school, airport)) Used by small and medium-sized businesses. Connected using twisted pair cables or coaxial cables. Wireless technology is being used within LANs. Radio & microwave signals are used to transmit data instead of cables

Internet & Communications Technology Wide Area Networks (WANs) Covers a wide geographical area. Not linked by coaxial or twisted pair cables Communication is possible via the use of fibre-optic cables and telephone lines, satellite and microwave technology. Large volumes of data can be transmitted across a WAN

Internet & Communications Technology Metropolitan Area Networks (MANs) Large network spanning a city area or campus Usually interconnects a number of LANs The geographic scope falls in between a LAN and a WAN – ranges from several blocks of buildings to entire cities Depends on communication channels of moderate to high data rates

Internet & Communications Technology Types of Network Layouts There are 3 main types of layout of computer networks: Star Network Each computer is connected to a central hub. It has its own connection to the network A break in a cable will not affect the other computers Most expensive to install, but the quickest.

Internet & Communications Technology Types of Network Layouts Bus Network All computers are in a line. Cheap and reliable If the cable breaks, the network is split. Slower than star networks

Internet & Communications Technology Types of Network Layouts Ring Network The last computer is connected to the first computer forming a ring or loop. Slower than star networks

Internet & Communications Technology Transmission Media From the previous section, we noted that there are several types of media used to transmit data across networks There are two major categories: Cabled/Wired Media: Twisted Pair, Coaxial, Fiber-Optic Wireless Media Satellite, Microwave, Infra-red

Internet & Communications Technology Cabled/Wired Media Twisted Pair: Type of wiring where two conductors are twisted together to cancel out any electromagnetic interference from external sources. Cheap to acquire Relatively slow; transmits small volumes of data

Internet & Communications Technology Cabled/Wired Media (continued) Coaxial: electrical cable surrounded by conductive and insulating layers Faster, but more expensive than twisted pair cables. Used when voice and video transmissions are needed Also used when large amounts of data needs to be transmitted.

Internet & Communications Technology Cabled/Wired Media (continued) Fiber-Optic: Thin cables through which light passes. Data is transmitted via the light Allows fast and accurate transmission of large volumes of data Popular in telecommunication industry

Internet & Communications Technology Wireless Media Satellite: A station on the ground sends and receives signals from the satellite Bandwidth is traditionally approximately 100 GHz Microwave: Used in broadcasting and telecommunication transmissions Short wavelength More bandwidth in microwave spectrum

Internet & Communications Technology Wireless Media (continued) Infra-red: Used in short range communication among computer peripherals Data is transmitted via an infrared beam which is switched on and off to encode data.

Internet & Communications Technology Wireless Network Technology The popular wireless technologies that we use today are: Bluetooth Open wireless protocol used to exchange data over a short distance Uses a radio communication system, hence they don’t have to be in line of sight of each other to transmit data. Wi-Fi Used with certified products that belong to a class of wireless LAN devices Used as a synonym for IEEE 802.11 Installed in many PCs, video game consoles, smartphones, printers

Internet & Communications Technology Largest computer network system in the world. Consists of smaller networks connected together by a global public network. Often called the information superhighway or cyberspace Intranet: Private network that belongs to an organization, and is designed to be accessible only by the organization’s members, employees and authorized persons.

Internet & Communications Technology Extranet: When part of the intranet is made accessible to customers, partners, suppliers, or others outside the company.