Networks and the Internet Living Online Networks and the Internet Innovative Training Works Digital Literacy

Objectives Identify network fundamentals Identify the benefits and risks of network computing Identify the relationship between computer networks, other communication networks, and the Internet Living Online Back

Introduction Today, millions of people are using the Internet Conduct business, do research, or read the latest news Download software and files, “shop” on-line, play computer games, or look for employment opportunities Living Online Back

Introduction Number of users has been continuously increasing to hundreds of millions over the past few years What really is the Internet? How does it work? How did it start? How can we benefit from the Internet? Living Online Back

What is the Internet? The Internet, or simply the Net, is a collection of computer networks that link millions of different computers around the world. History of Internet Living Online Back

Why Information Superhighway? You can “travel” to any of the millions of computers that are hooked up to the Internet, computers that might be thousands of miles away. Living Online Back

How does Internet work? Data travels by being relayed from one computer on a network, to another computer in another network until it reaches its destination. Living Online Back

What is a computer network? A computer network is a group of connected computers that exchange information. Living Online Back

What are Protocols? Protocol is a standardized collection of rules and conventions so that computers can exchange information regardless of their type or brand. Living Online Back

Networks can be categorized: By Scale By Functional Relationship By Topology By Technology used Living Online Back

Types of Networks (By Scale) Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN) Living Online Back

Local Area Network (LAN) In LAN, computers are connected within a local area, such as an office, a home, or a school’s computer laboratory. Living Online Back

Metropolitan Area Network (MAN) MAN is a larger network than LAN. It usually covers several offices, buildings or schools, each with their own LAN but connected to one another in the same city or locale. Living Online Back

Wide Area Network (WAN) Computers in a WAN are much farther apart, such as in two different cities. This is used to connect Local Area Networks together over vast distances. Living Online Back

Networks (By Functional Relationship) Peer-to-Peer All computers in the network relatively have the same function. Client-Server Specially designated computers called servers are used for specialized tasks in serving the needs of other user-computers (called clients) on the network. Living Online Back

Networks (by Network Topology) Topology refers to the layout or structure of the network in relation with the flow of data. The most common types of topologies are: Star Linear Bus Ring Hybrid Living Online Back

Star Topology The most commonly applied topology. Uses a central device (hub) with cables extending in all directions. Living Online Back

Linear Bus Topology Uses one long cable (backbone) to which computers and other devices are attached. Living Online Back

Ring Topology Consists of several computers joined together to form a circle. Data moves from one computer to the next in one direction only. Living Online Back

Hybrid Topology Hybrid topology is a combination of different types of topology used in a network system to adapt to the different design of floors or rooms in a building. Living Online Back

What is Ethernet? Ethernet is a computer network technology used in a Local Area Network (LAN). It is one of the most widely implemented LAN standards. A signal on the Ethernet cables reaches every attached node in the network, a correct destination “address” is important to reach the intended recipient. Living Online Back

Network Interface Card To connect to a network, the PC must have a Network Interface Card (NIC). Wireless PC NIC Internal PC NIC (RJ45) Internal PC NIC (Coaxial) Living Online Back

Connection/Cabling Options Twisted Pair Coaxial Fiber Optics Wireless Living Online Back

Twisted Pair This is one of the most widely used communications media because it is inexpensive and widely available. Unshielded Twisted Pair (UTP) UTP with RJ45 connectors Living Online Back

Coaxial This is a cable with a center wire surrounded with insulation; usually used in cable TV. Living Online Back

Fiber optics Instead of transmitting electrical frequencies, a fiber optic cable transmits pulsating beams of light. It is made up of glass or plastic fibers. Living Online Back

Wireless More and more people now use wireless networking, also called Wi-Fi, to connect their computers at home or in the office. Living Online Back

The Hub Hubs are used to connect PCs together to form a network. Back Living Online Back

The Switch A switch works similar to a hub except that user connected to the switch has access to the full bandwidth. Living Online Back

The Router Routers examine the destination address of the information and pass it on to the appropriate segment(s) only. Living Online Back

Hub, Switch, and Router Hub Switch Router Living Online Back

Sample LAN Diagram UTP Cable Ethernet Card Hub/Switch Back Living Online Back

Benefits of Networking Reduces costs (don’t have to buy printer for each computer, etc.) More productivity (don’t have to transfer files by diskette, etc.) Increases communication Living Online Back

Disadvantages of Networking Dependency Security Risk Loss of Autonomy or Privacy Viruses Living Online Back

Roles of Network Administrator Managing the computer network Making sure network is working properly Responsible for network security Living Online Back

Getting Connected to the Net To connect your PC to the Internet, you must have the following basic requirements: Internet Service Provider Modem Telephone Line Internet Software (Web browser, e-mail, etc. Living Online Back

Types of Internet Connection Narrowband Dial-up ISDN Broadband DSL Cable Dedicated Leased Line (such as T1) Wireless (Wi-Fi) Living Online Back

The Modem Modem converts digital signals to analog signals and vice-versa in a process called modulation-demodulation. Living Online Back

Internet Service Providers ISP is a company that provides you connectivity to the Internet. Infocom ISP Bonanza MozCom Pacific Internet Sky Internet, etc. Roles & Responsibilities of ISP Living Online Back

Dial-up The most common type of connection for home users. Considered the slowest but have the reputation of being the most inexpensive. Connection rates for dial-up modems tend to fall at around 56 kbps. You cannot use the telephone for the Internet and phone calls for the same time. Living Online Back

Integrated Services Digital Network ISDN is a type of digital telephone connection that offers data transfer rates of up to 128 kbps. This can be a better than dial-up, however ISDN connections are considered still more or less outdated. Living Online Back

Digital Subscriber Line (DSL) Becoming widely available and can provide an excellent connection. Allows you to use the phone normally while connected to the Internet. DSL connections can be costlier than dial-up. DSL operates starting at 512 Kbps Living Online Back

Cable Offers very fast and reliable connections with a fixed monthly fee. It will not affect how you use your telephone. Offers data transfer rates of approximately 1 mbps to 6 mbps. Cable connections are not always available in all areas. Living Online Back

Dedicated Leased Line Directly connects your computer to your ISP’s network. Capable of transferring data at 1, 544, 000 bits-per-second, such as T1. Upload and download speeds are the same (symmetric) Much more expensive than cable or DSL connections. Living Online Back

Wireless (Wi-Fi) No cords or wires for as long as you are in a WiFi “hotzone”. Wireless broadband connections: Wi-Fi, Satellite broadband, Wireless DSL, and Wireless Digital Cable. Connection speeds ranging from as little as 256 Kbps to as much as 10+ Mbps. You have to stay within a certain radius to connect to a WiFi device. Living Online Back

Roles and Responsibilities of ISP Maintain connection Customer Support Technical Support Security Living Online Back

How did it start? In the 1960’s, there was a demand for computer networks to help scientists and researchers from widely dispersed areas. US Defense Department created ARPANET (Advanced Research Projects Agency Network) in 1969 ARPANET became the forerunner of today’s Internet. Living Online Back

Internet Services Electronic Mail (E-mail) World Wide Web (Web) Search & File Sharing (Google) Instant Messaging (IM) Internet Relay Chat (Chat, IRC) Newsgroups Living Online Back