How Networks Tie Computers Together-chapter 17(1).pptx

Computer Networks

1. How Networks Tie Computers Together Chapter 17

2. Type of network   LAN : Local Area Network , is a network that covers a small geographical area WAN : Wide Area Network , is a network that covers larger geographical areas PAN : is a Personnel Area Network HAN : is a Home Area Network CAN : Campus Area Network MAN : Metropolitan Area Network

3. Network Several computers using some network tools with a small geographical area. The purpose of the network is to connect computers together, exchange data, and provide shared access to hardware, and software solutions. Where data are saved on the server. Usually Network is made of: Server : a computer that serves many connected computers Client/Node: one of the connected computer Router : a device that establishes a connection between two networks Modem : establish a connection between the Internet and the network Data Packets Cable/wire

4. Network is made of - ( cont ) Hub : Hubs connect networking devices physically together. Hubs use   twisted pair cabling  to connect devices. and act as pathways and transmit the information regardless if a data packet is destined for the device connected or not. A switch :The switch does ‘filter and forwarding’., each computer is connected through a single line. However, the switch is smarter about where it sends data that comes in through one of its ports Router : A router is a device that routes packets from one network to another. uses IP addresses to figure out where to send packets. It Connect two different network together .

5. Servers Different kinds of servers File Server: A specialized computer with multiple hard drives that connect to PCs using the network (called clients or nodes) where data are stored and retrieved by the clients. Clients: Computers connected to network connected by the server. Internet Server : Connect to World Wide Web (WWW). Print Servers : Printers connected to everyone on the network used for printing.

6. How Computers Connect to Each Other (2) Network Interface To become part of a network, a computer/device uses a network interface to communicate with the local network’s backbone: High-speed Internet or network routes. Data packets passed in the network through the backbone Many wires/Cables are used in the backbone The combination of connector, circuitry, wiring, and wave determines the network’s bandwidth.

7. . How Computers Connect to Each Other (1) Connection in network can be made through : Twisted-Pair Wiring The type most used to physically connect a computer to a modem or router. In this type of wiring, two conductors of a single circuit are twisted together for the purposes of improving electromagnetic. Coaxial Cable Coaxial cable consists of a single copper wire, which is covered by plastic and braided copper that shields the center wire from electrical disturbances. Electrical signal flows through the center conductor; like that used for cable television. Fiber optic cable : carries 1 billion bits a second, depending on light, Hair-thin fibers consist of two layers of pure silica glass covered with a reflective  cladding , like a tunnel lined with mirrors. Varying pulses carry the data bouncing off the cladding Wireless : most nodes on modern networks connect to the switch or router via  Wi-Fi  radio signals infrared light

8. Type of network and network architecture Star Configurations : this is the most common configuration of computers for a Local Area Network (LAN) in which all nodes are individually connected to a central connection point, like a router or a switch. Network has two types of relations Peer to Peer network where each PC have equal relation or a peer-to-peer to other devices. This network exists at home or in small offices with less than 10 employees. Client/server network : where there exists a server and client and the server is in control and responds to the client’s request

9. How Data Travels Between Computers(1) Analogue Data , use carrier wave or carrier signal with amplitude and frequency. It is a regular or constant waveform. Whereas the Information wave is all the time irregular. Digital data is the most common way for transferring data using a data packets. IP address : Internet protocol addresses is an identifier for a computer on a TCP/IP network protocol route message TCP/IP : transmission control protocol: a collection of methods to connect servers on the network and to transfer data to a specific IP address. It is a universal standard

10. How Wi-Fi Makes Internet Portable All Wi-Fi networks use access point ( AP) : a network node connected directly to a wired local area network or to the Internet. Wireless nodes, called stations , ea ch have a transmitter/ receiver When a device connects to the network , it broadcasts a probe request identifying itself and connect within range . Connection can be point to point or extensions points.

11. How Data Travels Between Computers(2) How Digital Data Move in Packets? The organization of data packets varies to match the type of data they contain, and they may be called frames , segments , or blocks . And data packets include: Preambl e —Synchronizes the network nodes Destination Address —A single PC or all PCs on a network, IP address Source Address —The address of the computer from which the packet originated, IP Address Data Type —Defines the format used for the data Data —The actual data CRC —Cyclical Redundancy Check, which is used to spot transmission errors or missing errors : it is an algorithm that are calculated and compared at the data delivery

12. 4 . How Bluetooth Keeps Devices Connected Bluetooth , named for the Danish King Harald Bluetooth, a Scandinavian , is a standard protocol for unifying wireless voice and data communications among different devices. It connects all the equipment through one universal short-range radio link. It is incorporated in a radio module , a microchip that can send both voice and data signals for about 30 feet/ 10 meters.

13. 4 . How Bluetooth Keeps Devices Connected Bluetooth protocol has a link manager (LM) software . The LM software identifies other Bluetooth devices , creates links with them for voice or data, and sends and receives data. After a link is established, Bluetooth sends data in packets or correction in case a packet is dropped .

14. Bluetooth modes

15. 4 . How NFC Lets Smart Devices Make Close Calls NFC (Near F ield C ommunications): I s a short-range wireless technology that allows the exchange of data between devices . It only works with short distances of about four inches at the most . NFC uses magnetic fields to communicate.

16. Cont. How NFC Lets Smart Devices Make Close Calls NFC devices can be passive or active : A passive NFC contains information that other devices can read and can’t receive any information other devices may have to offer. Examples: the nametags that unlock doors, and authorize elevators to stop on a particular floor. Active NFC devices can both send and receive information. They can decide if another device has the right to read the information they have, and the ability to grant or refuse another device to change the information they have. Examples: using smartphones to exchange business cards or playlists . With apps such as Google Wallet on Android phones, you can simply tap your device to pay at stores.

17. The data in an NFC session could be intercepted by other devices. For that reason NFC communications that involve such info as a credit card or bank account number are sent along secure channels and encrypted. Users can add antivirus software to smartphones and store sensitive data behind a password . Cont. How NFC Lets Smart Devices Make Close Calls