Networks and Communication Devices PDF

Comp 101: Introduction to Computing Chp 7: Networks and Communication Devices 1 ©2024 Mphago B. Botswana International University of Science and Technology Overview This chapter covers: – Net...

Comp 101: Introduction to Computing Chp 7: Networks and Communication Devices 1 ©2024 Mphago B. Botswana International University of Science and Technology Overview This chapter covers: – Networking concepts and terminology – What a computer network is and what it is used for – Other common networking and communications applications – Technical issues related to networks, including general characteristics of data transmission, and types of transmission media in use today – Explanation of the various communications protocols and networking standards in use today – Various types of hardware used with a computer network ©2024 Mphago B. Botswana International University of Science and Technology 2 What Is a Network? A network is a connected system of objects or people A computer network is a collection of computers and other hardware devices connected together so users can share hardware, software, and data, and electronically communicate – Converging with telephone and other communications networks – Range from small private networks to the Internet – Essential in most businesses ©2024 Mphago B. Botswana International University of Science and Technology 3 Wireless Power Powers/recharges devices via wireless signals and magnetic induction Two competing standards: Qi and PMA Requires charging surface; can use built-in or external charging receiver Charging surfaces may be built into walls, homes, cars, garage floors, etc. in the future With wireless charging, smartphones and other mobile devices can be recharged simply by placing them on a wireless charging surface. ©2024 Mphago B. Botswana International University of Science and Technology 4 Networking Applications The Internet – the largest computer network in the world Telephone service – POTS Network was one of the first networks Still provides telephone service to landline phones – Mobile phones (wireless phones) use a wireless network for communications Cellular (cell) phones must be within range of cell tower to function Dual-mode phones allow users to make telephone calls using more than one communications network – Cellular/Wi-Fi dual-mode phones Satellite phones communicate via satellite technology – Most often used by individuals such as soldiers, journalists, wilderness guides, and researchers ©2024 Mphago B. Botswana International University of Science and Technology 5 Broadcasting and GPS Applications Television and radio broadcasting – Over the air networks still used to deliver TV and radio content to the public – Also includes cable TV networks, satellite TV networks, and private closed-circuit television (CCTV) systems The global positioning system (GPS) uses 24 GPS satellites for location and navigational purposes – GPS receivers use the GPS system to determine their exact geographic location – GPS III is under development and will be more powerful and accurate than the current system ©2024 Mphago B. Botswana International University of Science and Technology 6 GPS Applications Individuals: Hiking, driving directions, maps, work data, Web searches, social media, etc. Workers: Location information, guide vehicles and equipment, emergency workers, etc. Military: To guide munitions and trucks, and to track military aircraft, ships, and submarines ©2024 Mphago B. Botswana International University of Science and Technology 7 Monitoring Systems Monitoring systems use networking technology to determine the current location or status of an object – RFID-based systems Monitor the status of objects – GPS-based monitoring systems Monitor the physical location of objects Vehicle and child monitoring systems – Electronic medical monitors Home healthcare – Sensor systems Shipping, home automation (smart thermostats), etc. ©2024 Mphago B. Botswana International University of Science and Technology 8 Multimedia Networking Multimedia networking involves distributing digital multimedia content, typically via a home network – Smart TVs, streaming media players, etc. Placeshifting - Allows individuals to view multimedia content at a more convenient location (i.e., Slingbox) ©2024 Mphago B. Botswana International University of Science and Technology 9 Videoconferencing, Collaborative Computing, and Telecommuting Videoconferencing uses computers, video cameras, microphones, and networking technologies to conduct face- to-face meetings over a network – Telepresence videoconferencing more closely mimics a real-time meeting environment Collaborative computing (workgroup computing) enables individuals to work together on documents and projects – Markup tools, collaboration software, shared documents, etc. With telecommuting, individuals work from a remote location (usually home) and communicate with their places of business and clients using networking technologies – Allows for employee flexibility – Greener computing ©2024 Mphago B. Botswana International University of Science and Technology 10 Telepresence Videoconferencing ©2024 Mphago B. Botswana International University of Science and Technology 11 Telemedicine Telemedicine uses networking technology to provide medical information and services – Remote monitoring and consultations – Remote diagnosis – Provides individuals in rural locations access to medical care – Necessary for long-term space exploration – Telesurgery involves robot-assisted surgery where doctor’s physical location is different from that of the patient and robot ©2024 Mphago B. Botswana International University of Science and Technology 12 Examples ©2024 Mphago B. Botswana International University of Science and Technology 13 Network Characteristics A wired network is a network in which computers and other devices are physically connected to the network with cables – Found in schools, businesses, and government facilities A wireless network is a network in which computers and other devices are connected to the network without physical cables – Data is typically sent via radio waves – Found in homes, schools, and businesses – A public wireless hotspot is a location that provides wireless Internet access to the public ©2024 Mphago B. Botswana International University of Science and Technology 14 Network Topologies The physical topology of a network indicates how the devices in the network are arranged – Star network: All network devices connect to a central device If the central device fails, the network cannot work – Bus network: All network devices connect to a central cable – Mesh network: Network devices are interconnected so that messages can take any of several possible paths ©2024 Mphago B. Botswana International University of Science and Technology 15 Basic Network Topologies ©2024 Mphago B. Botswana International University of Science and Technology 16 Client-Server Networks Client-server networks – Client: A computer or other device on the network that requests and utilizes network resources – Server: The computer dedicated to processing client requests ©2024 Mphago B. Botswana International University of Science and Technology 17 Peer-to-Peer (P2P) Networks P2P networks – All computers work at the same functional level – Users have direct access to the computers and devices attached to the network – Internet P2P networks Content is exchanged over the Internet directly between users ©2024 Mphago B. Botswana International University of Science and Technology 18 Network Size and Coverage Area Personal area networks (PANs) connect an individual’s personal devices – Devices must be physically located close together Local area networks (LANs) connect devices located in a small geographic area Metropolitan area networks (MANs) cover a metropolitan area such as a city or county – A metropolitan area network (MAN) is a computer network that is larger than a single building local area network (LAN) but is located in a single geographic area that is smaller than a wide area network (WAN).... It may also refer to public use networking infrastructure in a municipality or region Wide area networks (WANs) cover a large geographic area – The Internet ©2024 Mphago B. Botswana International University of Science and Technology 19 Intranets, Extranets, and VPNs An intranet is a private network designed to be used by an organizations’ employees – Set up like the Internet An extranet is a company network accessible by authorized outsiders A virtual private network (VPN) provides a private, secure path over the Internet – Provides authorized secure access to a private network via the Internet – Uses tunneling and special encryption technology – Without a VPN, passwords, credit card numbers, etc. sent via a hotspot can be intercepted ©2024 Mphago B. Botswana International University of Science and Technology 20 Data Transmission Characteristics Bandwidth is the amount of data that can be transferred in a given period of time – Measured in bits per second (bps), Kbps (thousands), Mbps (millions ), or GFbps (billions) Analog signals vs. digital signals – Analog: Data is represented by continuous waves Modulating a continuous beam of electromagnetic particles Conventional telephones – Digital: Data is represented by two discrete states (0s and 1s) ©2024 Mphago B. Botswana International University of Science and Technology 21 Transmission Type and Timing Serial transmission: Data is sent one bit at a time, one after another, along a single path – Typically used with networking media Parallel transmission: Data is sent in a group of bits with each bit taking a different path – Most often used within computer components ©2024 Mphago B. Botswana International University of Science and Technology 22 Ways of Timing Serial Transmissions Synchronous transmission – Blocks of data are transferred at regular, specified intervals – Most data transmissions within a computer and over a network are synchronous Asynchronous transmission – Data is sent when ready without being synchronized – Start bits and stop bits used to identify the bits that belong in each byte Isochronous transmission – Data is sent in time to be delivered at the time it is needed ©2024 Mphago B. Botswana International University of Science and Technology 23 Examples of Transmission Timing ©2024 Mphago B. Botswana International University of Science and Technology 24 Transmitted Data Direction Simplex transmission – Data travels in a single direction only – Relatively uncommon Half-duplex transmission – Data travels in either direction but only one way at a time – Used with some network transmissions Full-duplex transmission – Data travels in both directions at the same time – Most often used with network transmissions ©2024 Mphago B. Botswana International University of Science and Technology 25 Delivery Methods Circuit switching – Dedicated path over a network is established between sender and receiver; all data follows that path Packet switching – Messages are separated into small units called packets and travel along the network separately; packets are reassembled once destination is reached Broadcasting – Data is sent out to all other nodes on the network and retrieved only by the intended recipient; primarily used with LANs ©2024 Mphago B. Botswana International University of Science and Technology 26 Examples of Data Delivery Methods ©2024 Mphago B. Botswana International University of Science and Technology 27 Wired Networking Media Twisted-pair cable – Pairs of insulated wires twisted together – Used for telephone and network connections (LANs) Coaxial cable – Thick center wire surrounded by insulation – Used for computer networks and cable television delivery Fiber-optic cable – Utilizes hundreds of thin transparent clear glass or plastic fibers over which lasers transmit data as light – Used for high-speed communications ©2024 Mphago B. Botswana International University of Science and Technology 28 Examples ©2024 Mphago B. Botswana International University of Science and Technology 29 Wireless Networking Media With wireless networking media, data is sent through the airwaves using radio signals – The electromagnetic spectrum is the range of common electromagnetic radiation (energy) Radio frequencies are assigned by the FCC and are measured in hertz (Hz) Different parts of the spectrum have different properties, which make certain frequencies more appropriate for certain applications Wireless spectrum is the RF band (up to 300 GHz) – Unlicensed frequencies can be used for any application – Wireless networks often use frequencies in the 2.4GHz and 5 GHz bands ©2024 Mphago B. Botswana International University of Science and Technology 30 The Electromagnetic Spectrum ©2024 Mphago B. Botswana International University of Science and Technology 31 The Electromagnetic Spectrum ©2024 Mphago B. Botswana International University of Science and Technology 32 Cellular Radio Transmissions Cellular radio transmissions use cellular towers within overlapping honeycomb-shaped zones called cells – Calls are transferred from cell tower to cell tower as the individual moves – Cell tower forwards call to the MTSO – MTSO routes call to the recipient’s phone – Data sent via cell phones works in similar manner The speed of cellular radio transmissions depends on the type of cellular standard being used ©2024 Mphago B. Botswana International University of Science and Technology 33 How Cellular Phones Work ©2024 Mphago B. Botswana International University of Science and Technology 34 Microwave and Satellite Transmissions Microwaves use high-frequency radio signals that are sent and received using microwave stations or satellites – Signals are line of sight, so microwave stations are usually built on tall buildings, towers, mountaintops Microwave stations are earth-based stations that transmit signals directly to each other within a range of 30 miles – Stations designed to communicate with satellites (television and Internet services) are called satellite dishes ©2024 Mphago B. Botswana International University of Science and Technology 35 Communication Satellites Communication satellites are launched into orbit to send and receive microwave signals from earth – Traditional satellites use geosynchronous orbit 22,300 miles above the earth – A delay of less than one half-second is common when signals travel from earth to satellite and back – Low earth orbit (LEO) satellites have less delay and are used with satellite telephones – Medium earth orbit (MEO) satellites are most often used for GPS systems ©2024 Mphago B. Botswana International University of Science and Technology 36 Example of How Satellite Internet Works ©2024 Mphago B. Botswana International University of Science and Technology 37 Infrared (IR) Transmissions Infrared (IR) transmissions send data as infrared light rays – Like an infrared television remote, requires line of sight – Because of this limitation, many formerly IR devices (wireless mice, keyboards) now use RF technology IR is sometimes used to beam data between some mobile devices, game consoles, and handheld gaming devices ©2024 Mphago B. Botswana International University of Science and Technology 38 Comm Protocols and Networking Standards Protocol – A set of rules for a particular situation – Communications protocol A set of rules that determine how devices on a network communicate Standard – A set of criteria or requirements approved by a recognized standards organization – Address how networked computers connect/communicate – Needed to ensure products can work with other products ©2024 Mphago B. Botswana International University of Science and Technology 39 TCP/IP TCP/IP is the most widely used communications protocol – Consists of two protocols Transmission Control Protocol (TCP) – Responsible for delivery of data Internet Protocol (IP) – Provides addresses and routing information – Uses packet switching to transmit data – TCP/IP support is built into almost all operating systems IP addresses are used to identify computers and devices on networks ©2024 Mphago B. Botswana International University of Science and Technology 40 Other Internet Communications Protocols HTTP (Hypertext Transfer Protocol) and HTTPS (Secure Hypertext Transfer Protocol) – Used to display Web pages FTP (File Transfer Protocol) and SFTP (Secure File Transfer Protocol) – Used to transfer files over the Internet SMTP (Simple Mail Transfer Protocol and POP3 (Post Office Protocol) – Used to deliver e-mail over the Internet ©2024 Mphago B. Botswana International University of Science and Technology 41 Ethernet (802.3) Ethernet (802.3) is the most widely used standard for wired networks – Typically used with LANs that have a star topology – Works with twisted-pair, coaxial, and fiber-optic cabling – Continually evolving – Most common today are Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet – 40 Gigabit Ethernet and 100 Gigabit Ethernet standards ratified in 2010 – 400 Gigabit and Terabit Ethernet standards are currently being explored ©2024 Mphago B. Botswana International University of Science and Technology 42 Ethernet Standards ©2024 Mphago B. Botswana International University of Science and Technology 43 Power over Ethernet (PoE) PoE allows electrical power to be sent along the cables on an Ethernet network along with data – Devices are not plugged into an electrical outlet as long as they are connected to Ethernet ports that support PoE PoE injector can be used to send power to the device if needed – Most often used in business networks with remote devices (outdoor networking hardware, cameras, etc.) – Can also be used to place networked devices near ceilings or other locations where a nearby power outlet may not be available ©2024 Mphago B. Botswana International University of Science and Technology 44 Examples of PoE Devices ©2024 Mphago B. Botswana International University of Science and Technology 45 Wi-Fi (802.11) Wi-Fi (802.11) is a family of wireless networking standards using IEEE standard 802.11 – Current standard for wireless networks in homes and offices – Built into many everyday objects today – Designed for medium-range transmission; speed and distance depends on Wi-Fi standard, solid objects in the way, interference, etc. ©2024 Mphago B. Botswana International University of Science and Technology 46 WiMAX (802.16) WiMAX (802.16) is a set of standards for longer range wireless networking connections, typically MANs – Fixed WiMAX Designed to provide Internet access fixed locations (hotzones) Typical hotzone radius is between 2 and 6 miles Possible to provide coverage to an entire city by using multiple WiMAX towers – Mobile WiMAX (802.16e) Mobile version of the standard Being replaced with cellular standards ©2024 Mphago B. Botswana International University of Science and Technology 47 Example of WiMAX vs. Wi-Fi Coverage ©2024 Mphago B. Botswana International University of Science and Technology 48 Cellular Standards First Generation – Analog and voice only 2G – Digital, both voice and data, faster 3G – A current standard, uses packet switching – Typical speeds are between 1 and 4 Mbps – HSDPA/UMTS, EV-DO 4G – A faster current standard, uses packet switching – Typical speeds are between 3 to 15 Mbps – LTE, LTE-Advanced, LTE-Unlicensed (LTE-U) 5G – Next generation; under development ©2024 Mphago B. Botswana International University of Science and Technology 49 Bluetooth Bluetooth is a networking standard for very short- range wireless connections – Typical range is about 10 meters (33 feet) – Designed to connect devices wirelessly Keyboard/mouse to a PC, send print jobs to a printer, connect a wireless speaker to a smartphone, send photos from a smartphone to another smartphone or a PC, etc. – Can transmit through clothing or other objects – Devices form piconets when connected (8 devices max) – Bluetooth 4 (Bluetooth Smart) is energy efficient ©2024 Mphago B. Botswana International University of Science and Technology 50 Networking Hardware A network adapter is used to connect a computer to a network – Also called network interface card (NIC) when in the form of an expansion card A modem is a device that enables a computer to communicate over analog networking media – Term is often used interchangeably with network adapter Most computers and mobile devices today come with a built-in network adapter and/or modem ©2024 Mphago B. Botswana International University of Science and Technology 51 Examples of Network Adapters and Modems ©2024 Mphago B. Botswana International University of Science and Technology 52 Switches and Routers A switch is a central device that connects devices in a wired network but only sends data to the intended recipient – Contains ports to which devices are connected – Hub is similar but sends data to all recipients A router connects multiple networks: Two LANs, two WANS, LAN and the Internet, etc. – Passes data to intended recipient only – Can plan the most efficient path – Are used to route traffic over the Internet ©2024 Mphago B. Botswana International University of Science and Technology 53 Wireless Access Points, Wireless Routers, and Bridges A wireless access point allows devices to connect to a network A wireless router is a router with a built-in wireless access point and, typically, a switch – If so, it can connect both wireless and wired devices to a network and connect that network to the Internet – Travel and mobile broadband routers are available A bridge is used to connect two LANs together – In a home network, often used to wirelessly connect a group of wired devices (TV, Blu-ray player, etc.) to a home network ©2024 Mphago B. Botswana International University of Science and Technology 54 Examples of Wireless Routers ©2024 Mphago B. Botswana International University of Science and Technology 55 Other Networking Hardware Repeaters amplify signals along a network Range extenders are repeaters for a wireless network Antennas are devices used for receiving or sending radio signals – Some network adapters and routers can use an external antenna – Can be directional or omnidirectional – Strength measured in decibels (dB) Multiplexers combine transmissions from several different devices to send them as one message – Frequently used with fiber-optic cables and other high-capacity media to increase data throughput ©2024 Mphago B. Botswana International University of Science and Technology 56 Examples of Networking Hardware ©2024 Mphago B. Botswana International University of Science and Technology 57  Any Questions? ©2024 Mphago B. Botswana International University of Science and Technology 58