Computer Technology Notes #4 Networks Computer Technology Notes #4

Network A network is two or more computers and other devices (printers or scanners) that are connected, for the purpose of sharing data and programs

Advantages of Networks Communication E-mail, chat rooms, telephone, video telephone, video conferencing Sharing hardware Printers Sharing files and data Users can access data from other computers on the network, including the server

Advantages of Networks Sharing software Users can run programs from remote computers on the network Security of data Information preservation

Network Terms File Server Host Computer A computer connected to a network that distributes resources to other users Contains the software to manage and process files for other network users Host Computer Refers to any computer that provides services to network users This term is used more commonly with computers on the Internet IBM Server Commercial

Network Terms Workstation Client Refers to a personal computer connected to a network Example Each computer in the classroom Client Refers to the software on a computer that allows the user to access the server Example: Windows

Network Interface Card (NIC) Small circuit board that converts the digital signals from a computer into signals that can travel over a network Desktop Computers have the NIC inside the case with a port on the outside for the network cable Example: Our classroom computers

Network Connection Devices Hubs (Switches) A device that connects several components of a network Routers (Gateways) A device that connects at least two networks

Firewalls This is part of a network that is designed to block unauthorized access to the network while allowing authorized access Firewalls can be implemented in software or hardware or both

Physical Infrastructure Physical infrastructure refers to cables, modems, switches, and routers. Twisted-pair – Two insulated wires twisted around each other; the same type of wire as that used for telephones

Physical Infrastructure Coaxial cable – Consists of an insulated center wire surrounded by a layer of braided wire; the same type of wire as that used for cable TV Fiber-optic cable – Type of fiber glass cable that transmits data in the form of light impulses; can carry more data for longer distances than other wire

Wireless Networks (no wires involved) Wireless communication across networks or within a network can be achieved through the following technologies: Satellite Microwaves Radio waves (cell phone systems, wireless LANs, home networks) Infrared technology-must be in a line of sight, such as a mouse

Bandwidth Bandwidth is the amount of data that can be transmitted through a communications channel. Digital bandwidth is measured in bits per second (bps), kilobits per second (Kbps), megabits per second (Mbps), or gigabits per second (Gbps).

Local Area Network (LAN) Computer network that is located within a limited geographical area, such as a school or small business Example: The network in our classroom

Wide Area Network (WAN) Interconnected group of computers and peripherals that cover a large geographical area, such as multiple buildings Examples The Jordan School District Network The Internet

Packet Switching Demonstration The Internet is a packet switching network: Outgoing messages are divided into fixed-size data units called packets. Packets are numbered and addressed to the receiving computer. Routers examine the packets and send them to their destination. Packet Switching Demonstration

IP Addresses A unique identifying number assigned to each computer connected to the internet Example – 204.127.102.001 Each computer on a network should have its own separate IP Address or conflicts will occur when there are duplicate addresses