21. From Analog to Digital Analog Most phenomena in life are analog. Analog signals use wave variations, continuously changing.Sound, light, and temperature are analog forms.Traditional TV and radio use analog signals.Humans' vision operates in analog mode.
14Peer to PeerAll computers on the network are "equal" and communicate directly with one another, without relying on a server.Easy to setupLess expensiveWork effectively for up to 25 computersSlow down under heavy use
15Client-Server Clients are microcomputers that request data. Servers are central computers used to supply data.File server is a computer acts like a disk drive, storing the programs and data files.Database server is a computer that stores data but doesn’t store programs.Print server controls one or more printers and stores the print-image output.Web server contains web pages.Mail server manages .
165. IntranetIntranet is an organization’s internal private network that serves employee only.
176. ExtranetExtranet is private intranets that connect internal personnel and selected suppliers and other parties such as purchasing, production planning.
187. VPN (Virtual Private Networks) VPNs use a public network (usually the internet) plus intranets and extranets to connect an organization's various sites but on a private basis, via encryption and authentication; regular internet users do not have access to the VPNs data and information.
198. Firewall Protect Network from Intruders FIREWALL Networking Basic https://www.youtube.com/watch?v=-xnqC2aPb00Software Firewall > One computerHardware Firewall > Many computers
249.1 Host & Nodes Host computer controls the network Node is any device that is attached to a network.ComputerStorage devicesScannerPrinter
259.2 Packet A packet is a fixed-length block of data for transmission. A sending computer breaks an electronic message apart into packets, each of which typically contains bytes.https://www.youtube.com/watch?v=3_EHaM3tr98
269.3 ProtocolProtocol is a set of conventions governing the exchange of data between hardware and software components in a communication network.
29SwitchA switch is a device that connects computers to a network and facilitates communication by sending message between sender and receiver nodes.
309.4.2 BridgeA bridge is a device used to connect two similar networks, LAN and LANA bridge has a single connection point.
319.4.3 GatewayA gateway is an interface permitting communication between dissimilar network, LAN and WAN
329.4.4 RouterRouters are specialized devices for transmitting data, physical devices that join multiple networks.Router calculates the best possible transmission path of data packets between networks.
339.5 Network Interface Card Network interface card enables the computer to send and receive messages over a cable network.
36StarAll computers and other communication devices are directly connected to a switch.The switch prevents collisions between messages.If a connection is broken, the rest of the devices will continue operating.If the switch goes down, the entire network stops.
38RingAll computers and other devices are connected in a continuous loop.Messages are passed around the ring until they reach the destination.There is no central server.Messages flow in one direction. Thus, there is no collisions.If one node malfunctions, the entire network can stop working.
40Bus All nodes are connected to a single wire. The bus has two endpoints, which stop the network signal.AdvantageIf some message collide, the sending device waits and tries to transmit again.Inexpensive, easy to use, good for small networkDisadvantageNeed extra software to avoid collisionLimited to 20 devicesCannot exceed 185 meters in length
44MeshEach node has more than one connection to the other nodes so that a message can take any possible shortest, easiest route to reach its destination.If a path between two nodes is disrupted, data can be automatically rerouted along another path.
4511. Wired Communications Media Twisted-pair wireCoaxial CableFiber-optic cable
53Fiber-optic CableA fiber-optic cable consists of dozens of thin strands of glass or plastic that transmit pulsating beams of light rather than electricity.A fiber-optic cable can carry data at the rate of 2 gigabits per second.It is not affected by electromagnetic interference.It has a much lower error rate than telephone wire.It requires less power to transmit signals than co-ax cable.
5812. Wireless Communications Media 12.1 Infrared Transmission 12.2 Broadcast Radio 12.3 Cellular Radio 12.4 Microwave Radio 12.5 Communications Satellites
5912.1 Infrared Transmission Infrared wireless transmission sends data signals using infrared-light waves at a frequency too low for human eyes to receive and interpret.Infrared port can be found on TV remote-control.1-16 megabits per second
6012.2 Broadcast RadioBroadcast radio is a wireless transmission medium that send data over long distances at up to 2 megabits per second.Broadcast radio is used in AM and FM radio station.
6112.3 Cellular RadioCellular radio is used for cellphones and wireless modems, using high-frequency radio waves to transmit voice and digital messages.
6212.4 Microwave RadioMicrowave radio transmits voice and data at 45 megabits per second through the atmosphere as super high-frequency radio waves.
6312.5 Communication Satellite Communications satellites are microwave relay stations in orbit around Earth.
6513. Long-Distance Wireless One-way Communication > GPS, PagerTwo-way Communication > 4G
6614. Short-Distance Wireless Local area networks > range feet > Wi-FiPersonal area networks > range feet > BluetoothHome automation network > range feet > Insteon https://www.youtube.com/watch?v=YpuqceW3qu8