Our Digital World Second Edition

Our Digital World Second Edition
Chapter 6 Our Digital World Second Edition Chapter 6 Communications and Network Technologies: Connecting Through Computers Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

This chapter will help you be able to:
Define computer networking and its uses. Describe a communications system and how data is exchanged. Distinguish various types of transmission media. Recognize the role of network standards and protocols. Describe various networking devices and software. Explain the importance of network security. When you finish this chapter you should be able to: Bullet 1: Define what computer networking is, and how it’s used both at work and at home. Bullet 2: You should be able to describe what makes up a communications system, and how it enables a sender and receiver to exchange data. Bullet 3: This chapter helps you distinguish among various types of transmission media that are used for both wired and wireless networks. Bullet 4: You’ll be able to identify the role of network standards and protocols, which are used in communications to ensure that a variety of systems can interact with each other. Bullet 5: You will learn about networking devices such as routers and access points, and how software can help an administrator control a network. Bullet 6: Finally, this chapter explores the role of network security, a topic you will learn more about in Chapter 8 of the textbook. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

© Paradigm Publishing, Inc.
Chapter 6 Main Topics 6.1 How Does the World Use Networking? 6.2 Exploring Communications Systems 6.3 Transmission Systems 6.4 Communications Standards and Protocols 6.5 Network Classifications 6.6 Networking Devices and Software 6.7 Securing a Network 6.8 Interesting Trends in Networking The main topics covered in Chapter 6 are: Bullet 1: How Does the World Use Networking? Bullet 2: Exploring Communications Systems Bullet 3: Transmission Systems Bullet 4: Communications Standards and Protocols Bullet 5: Network Classifications Bullet 6: Networking Devices and Software Bullet 7: Securing a Network Bullet 8: Interesting Trends in Networking Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Why Should You Care? Communications systems allow computing devices to send and receive data. Networks allow sharing of files, Internet connections, and devices. Bullet 1: If we didn’t have communications systems, your computer and mobile phone couldn’t connect with the outside world. You couldn’t send and receive s, download music, or upload a video to YouTube. Bullet 2: Whether you’re using the worldwide network called the Internet, or sharing resources across a home network, you can become more efficient and productive by using a network. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

6.1 How Does the World Use Networking?
Chapter 6 6.1 How Does the World Use Networking? Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

The Many Uses of Networks
Chapter 6 The Many Uses of Networks A way to share files and resources. Communicate with others. Intranets and extranets. Home networks. The Internet. Bullet 1: A computer network involves two or more computers which are set up to communicate with each other to share resources such as files or software. Bullet 2: Networks allow you to communicate with people, from friends and family to employees and customers. Bullet 3: Many companies have an internal network, called an intranet, that is like a private Internet within their “walls.” Some companies extend their internal network to vendors or others via an extranet. Bullet 4: Home networks allow you to share resources among family members. You might share your printer or an Internet connection, for example. Bullet 5: The Internet is a global network, made up of several networks that are linked together. By tapping into the Internet’s resources, you can find a wealth of information, services, and connections with others. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 computer network intranet extranet The section 6.1 terms to know are: computer network: Two or more computing devices connected by a communications medium, such as a wireless signal or a cable. intranet: A private network within a company’s corporate “walls.” extranet: An extension of an intranet that allows interaction with suppliers, customers, and others outside of the company. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… The Internet is a global network of microwave towers. social networks. several networks linked together. intranets. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

6.2 Exploring Communications Systems
Chapter 6 6.2 Exploring Communications Systems Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Communications Systems Illustrated
Chapter 6 Communications Systems Illustrated Communications systems are made up of: The computer being used to browse the Internet. Transmission media over which data travels, such as a satellite or microwave towers. A set of standards and network protocols which govern how data is handled when travelling on the channel. Hardware and software to connect the sending and receiving ends to the path that data follows. A computer network is a communications system. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Types of Signals Analog and digital. Voice transmitted as analog on phone lines. Computers require a digital signal. Newer technologies don’t require the conversion. Bullet 1: Two types of signals can carry your voice across a communications system: analog and digital. Bullet 2: Traditionally, analog was used to carry your voice over a phone line. Bullet 3: Because computers can’t “speak” analog, they require that the analog signal be demodulated to a digital signal using a piece of equipment called a modem. (This slide includes a picture of a modem.) Bullet 4: Recent communications technologies use digital signals, so this conversion is unnecessary in many cases. For example, television transmissions ceased to be analog in 2009 when that industry switched to digital. Recent computer networks use only digital to transmit data over the network. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Analog and Digital Signals
Chapter 6 Analog and Digital Signals As this illustration shows, an analog signal is formed by continuous sound waves that fluctuate over a range from high to low. A digital signal has two states: high or low. High is represented by the digital bit 1, and low is represented by 0. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Transmission Speed Data moves at different speeds. Frequency and bandwidth. Network traffic. Broadband allows the transmission of a large amount of data at fast speed. Bullet 1: As you’ve experienced if you download files from the Internet, data moves at different speeds across a communications system. Various conditions affect the speed, such as the amount of traffic on that network at any point in time. Bullet 2: Two factors have a significant impact on transmission speed: frequency and bandwidth. Frequency is the speed at which a signal can change from high to low. If you have a higher frequency connection, you get faster transmissions. Bandwidth relates to how much data the channel can handle. The lower the bandwidth, the fewer bits per second can be transmitted. Bullet 3: The speed at which your data is transmitted will decrease when many others are using the same connection, just as you cannot drive as fast on a highway when there are a lot of other cards sharing the road. Bullet 4: Broadband channels can carry a lot of data at a fast speed, meaning they have a high frequency and high bandwidth. Typically, the higher the connection speed, the higher the cost. However, the benefits of 50 megabits per second with a cable connection over 56 kilobits per second using a dial up-phone line can be dramatic. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Frequency Speeds A high-frequency signal that quickly changes from high to low travels faster. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 communications system network protocol analog signal digital signal modem frequency bandwidth The section 6.2 terms to know are: communications system: In the context of a computer network, a system that includes sending and receiving hardware, transmission and relay systems, common sets of standards so all the equipment can “talk” to each other, and communications software. network protocol: A rule for how data is handled as it travels along a communications channel. analog signal: An electronic signal formed by continuous sound waves that fluctuate from high to low. Your voice is transmitted as an analog signal over traditional telephone lines at a certain frequency. digital signal: A discrete electronic signal that is either high or low. In computer terms, high represents the digital bit 1, and low represents the digital bit 0. modem: A piece of hardware that sends and receives data from a transmission source such as your telephone line or cable television connection. The word modem comes from a combination of the words modulate and demodulate. frequency: The speed at which a signal can change from high to low; a signal sent at a faster frequency provides faster transmission. bandwidth: The number of bits (pieces of data) per second that can be transmitted over a communications medium. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 broadband kilobit per second (Kbps) megabit per second (Mpbs) gigabit per second (Gbps) terabit per second (Tbps) petabit per second (Pbps) (Continued) broadband: Any communications medium that can carry a large amount of data at a fast speed. kilobit per second: A transmission at a rate of one thousand bits per second. megabit per second: A transmission at a rate of 1 million bits per second. gigabit per second: A transmission at a rate of 1 billion bits per second. terabit per second: A transmission at a rate of 1 trillion bits per second. petabit per second: A transmission at a rate of 1 quadrillion bits per second. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… The number of pieces of data that can be transmitted over a communications medium is called frequency. bandwidth. broadband. wavelength. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 6.3 Transmission Systems Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Wired Transmissions Wired networks still in use. Various types of cables: Coaxial Twisted-pair Fiber-optic Bullet 1: Wires connected all the hardware in older networks. Today wireless technologies are quickly taking over, but wired networks still exist. Bullet 2: Several types of cable might be part of a wired network, including coaxial, twisted-pair, and fiber-optic. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Wired Transmissions Coaxial Twisted-pair Fiber-optic Bullet 1: Coaxial cable is used for transmitting cable television signals at very fast speeds. Bullet 2: Twisted-pair cable consists of insulated wires wrapped around each other. They are found in wired telephone connections. For example, Cat 5 is a twisted-pair cable used in Ethernet networks. Bullet 3: Fiber-optic cable involves a string of glass that transmits beams of light. These transmissions are very fast and can transmit billions of bits per second. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Wireless Transmissions
Chapter 6 Wireless Transmissions Cellular, microwave, and satellite. Radio waves. Signal strength and frequency. Bullet 1: Currently, three kinds of wireless transmission systems are in use: cellular, microwave, and satellite. Bullet 2: All use radio waves for transmitting data. Bullet 3: Each system transmits data in different ways, and the systems vary in signal strength and frequency. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Cellular Technology Networks like those used by cell phones send transmissions via cell towers. Each tower has a range called a cell. The towers can transmit both voice and data in any direction. The current generation of cellular is 4G (fourth generation) which transmits digital signals at speeds up to 15 Mbps. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Microwave Technology Microwaves move high-frequency radio signals from one microwave tower to another. Because the signal can’t bend around objects, towers must be in sight of each other. Microwave signals can also bounce off a satellite. You might see a microwave system used on a college or business campus, for example. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Satellite Communications
Chapter 6 Satellite Communications To solve the problem of signals that can’t travel around obstructions, satellite communications send microwave signals up into the air. The signals bounce off a satellite and then return to an Earth-based station. Satellite is typically used in rural areas where microwave or cellular towers aren’t available. Video conferences and air navigation control also use satellite communication. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 twisted-pair cable coaxial cable fiber-optic cable cellular network cellular transmission microwave satellite communication The section 6.3 terms to know are: twisted-pair cable: A type of cable consisting of two independently insulated wires twisted around each other. This type of cable is used to transmit signals over short distances, such as connecting a home’s hardware telephone system or an Ethernet network. coaxial cable: A cable used to transmit cable television signals over an insulated wire at a fast speed (millions of bits per second). fiber-optic cable: A transmission medium that uses a protected string of glass which transmits beams of light. Fiber-optic transmission is very fast, sending billions of bits per second. cellular network: A transmission system that sends signals through a cell tower. Every cell tower has its own range or cell of coverage. This system is used to transmit both voice and data in any direction. cellular transmissions: Signals sent using a cell tower. microwave: A high-frequency radio signal sent from one microwave tower to another. Because the signal cannot bend around obstacles, towers must be positioned in line of sight of each other. satellite communication: Space-based equipment that receives microwave signals from an earth-based station and then broadcasts the signals back to another earth-based station. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… A cellular network sends transmissions using microwave towers. T-lines. fiber-optic cable. cell towers. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

6.4 Communications Standards and Protocols
Chapter 6 6.4 Communications Standards and Protocols Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

What Are Standards and Protocols?
Chapter 6 What Are Standards and Protocols? Addressing issues of compatibility. Standards organizations. Communications standards called protocols. Bullet 1: The computer and telecommunications industries have established standards to enable the many types of computing devices to communicate with each other. These standards allow your mobile phone or your digital camera to communicate with your computer, for example. Bullet 2: Organizations such as the American National Standards Institute (abbreviated ANSI) or the Institute of Electrical and Electronics Engineers (abbreviated IEEE, which is pronounced eye-triple-E) develop and approve these standards. They specify how computers access transmission media, the speeds used on networks, and the design of networking hardware such as cables. Bullet 3: A standard that addresses how two devices communicate is called a protocol. A protocol is a set of rules that govern the transmission of data. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

The Changing World of Voice Communications
Chapter 6 The Changing World of Voice Communications According to Silverman, why are people starting to reject electronic voice communication? Why might telephone numbers disappear? Do advances in “Internet telephony” signal a renaissance in voice communications? Will video calling, like that offered by Apple FaceTime, become the norm? What might be the “next big thing” in the way people use technology to network with each other? Technology journalist Dwight Silverman discusses how technology is changing the dynamics of person-to-person communication. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Network Transport Standards
Chapter 6 Network Transport Standards Ethernet. Token ring. TCP/IP. Bullet 1: Three primary standards address the way data is transported in a network. The first is Ethernet, a wired media standard. The Ethernet standard specifies that no central device controls the timing of transmission. Instead, each device attempts to send data when it senses that the network is available. Bullet 2: The token ring standard allows devices to share a signal. The signal, called a token, is passed from one device to another. Only the device that holds the token at any point in time is allowed to transmit data. Bullet 3: TCP/IP is a standard that specifies the order in which data is sent. With the TCP/IP standard, data is divided into small packets. Breaking data into packets, sending, and then reassembling the data is called packet switching. The Internet is based on the TCP/IP standard. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Wireless Networking Standards
Chapter 6 Wireless Networking Standards Wi-Fi. WiMAX. Bluetooth. Radio Frequency Identification (RFID). Wireless Application Protocol (WAP). Bullet 1: Wireless transmissions use a variety of networking standards. One is Wi-Fi, which stands for wireless fidelity. Wi-Fi is based on the standard in its many versions, and it is often used to set up home networks. Many public hotspots offer Wi-Fi connections for free or for a fee. Your computer may be able to automatically detect a hotspot and connect to it. Bullet 2: WiMAX is the term for Worldwide Interoperability for Microwave Access which uses the 4G standard. This is the fourth generation broadband wireless standard. Compared to Wi-Fi, it is faster and operates over a longer range. Bullet 3: Bluetooth offers short range connections, from 3 to 300 feet, depending on the power class of your device. You can make hands-free calls while driving if your car can connect to your mobile device via Bluetooth, for example. Many devices contain Bluetooth chips, such as smartphones, laptops, keyboards, and digital cameras. Bullet 4: If you wander down a grocery store aisle, you may see someone checking inventory by scanning items with a RFID reader. This wireless technology is used to track inventory via radio signals. Items contain transponders or tags, which are read by the transceiver in the RFID reader. Bullet 5: Wireless application protocol is used for mobile devices. This standard controls how mobile phones display online information such as maps and . Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Mobile Internet Usage According to ComScore.com, social networking is the fastest growing category for U.S. mobile subscribers. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Public networks likely to be unsecured. Don’t access financial accounts. Secure your home wireless network. Bullet 1: Have you used a public hotspot to go online? Did you know that the connection is not secure? Bullet 2: Avoid performing financial transactions over a public network, such as checking your bank account balance. Bullet 3: Be sure to secure your home wireless network so that people in the vicinity can’t pick up your transmissions or piggyback on your connection. Next slide Playing It Safe © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 standards American National Standards Institute (ANSI) Institute of Electrical & Electronics Engineers (IEEE) protocol Ethernet The section 6.4 terms to know are: standards: Allow different devices to talk to one another. To ensure compatibility among devices, they specify how computers access transmission media, speeds used on networks, the design of networking hardware such as cables, and so on. American National Standards Institute (ANSI): One of several organizations that establishes network communications standards. Institute of Electrical and Electronics Engineers (IEEE): One of several organizations that establishes network communications standards. protocol: A standard that specifies how two devices will communicate by providing rules such as how data should be formatted and coded for transmission. The Internet transmission protocol is indicated in the first part of a website’s universal resource locator (URL). Ethernet: A standard that specifies that no central device controls the timing of data transmission. With this standard, each device tries to send data when it senses that the network is available. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 token ring token TCP/IP packet packet switching Wi-Fi standard hotspot (Continued) token ring: A standard that allows computers and other devices accessing a network to share a signal. This signal, called a token, is passed from device to device. Only the device that holds the token can transmit data at that time. token: A signal passed from device to device in a token ring network. TCP/IP: Short for Transmission Control Protocol/Internet Protocol. A protocol that breaks transmissions into small packets of data that are sent on the network. Each packet specifies the order in which the data is to be reassembled. This is the protocol for the Internet. packet: A small unit of data that is passed along a packet-switched network, such as the Internet. packet switching: The process of breaking data into packets, sending, and then reassembling the original data. Wi-Fi: Short for wireless fidelity. A wireless technology, based on the standard in its various versions such as a, g, or n, that is used to connect to the Internet via hotspots and radio waves. standard: A communications standard used in Wi-Fi networks that tells wireless devices how to connect with each other using a series of access points and radio frequencies to transmit data. hotspot: A location where Wi-Fi access is available. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 WiMAX Bluetooth tethering Radio Frequency Identification (RFID) Wireless Application Protocol (WAP) server webmail (Continued) WiMAX: The abbreviation for Worldwide Interoperability for Microwave Access. Also known as , this standard uses radio waves to connect with other devices using a WiMAX tower. It is faster and can work over a longer range than Wi-Fi. Bluetooth: A network protocol that offers short-range connectivity, from 3 to 300 feet, depending on a device’s power class, via radio waves between devices such as a cell phone and car. Bluetooth-enabled devices can communicate directly with each other. tethering: Cell phone users who can share Internet connection of their device via cable, Bluetooth, or Wi-Fi with another device such as a tablet or laptop. Radio Frequency Identification (RFID): A wireless technology primarily used to track and identify items using radio signals. An RFID tag placed in an item contains a transponder which is read by a transceiver or RFID reader. Wireless Application Protocol (WAP): Specifies how mobile devices such as cell phones display online information like maps and . server: A computer dedicated to managing the sending, receiving, and storing of messages. webmail: A web-based service such as Hotmail or Gmail that can be accessed from any computer connected to the Internet using a web browser. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… Computer standards allow different devices to talk to each other. data files to be decrypted. you to create messages. manufacturers to design computing devices. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

6.5 Network Classifications
Chapter 6 6.5 Network Classifications Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Types of Networks Local Area Networks (LAN). Metropolitan Area Networks (MAN). Wide Area Networks (WAN). The three main types of networks are categorized by the geographic area they cover. Bullet 1: The first is a local area network or LAN (shown in the bottom-left figure). You would use a LAN to connect devices in the same room, building, or in a few nearby buildings. One computer in a LAN is the server, and it contains the networking software and coordinates the data exchange among the network devices. In addition, shared files are stored on that server. You might also have a print server to manage printing tasks. A wireless LAN is called a WLAN. Bullet 2: Several LANs within a city or similar high-population area connected together in a higher-speed network is called a metropolitan area network, or MAN. Bullet 3: A wide area network, or WAN, serves even larger geographic areas (shown in the bottom-right figure). WANs allow data to be shared among networks worldwide. The Internet, for example, is an enormous wide area network. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Network Architecture Sharing network resources. Client/server. Peer-to-peer (P2P). Internet peer-to-peer (P2P). Bullet 1: Network architecture involves how computers in a network share resources. In a network, a computer could be the client making a request. Or, a computer might be a server responding to a request. Bullet 2: One type of architecture, client/server, has one server and many clients. This is called distributed application architecture because tasks are distributed among client and server computers. Bullet 3: Peer-to-peer architecture enables every computer on the network to work as either a client or a server. This type of network is simple to set up. However, it doesn’t work well if a network has heavy user demand because data becomes gridlocked. Bullet 4: A modification of peer-to-peer is Internet peer-to-peer. In this architecture, all connected devices share and access files. Users logged onto a peer-to-peer connection act as a server when they upload files on their computer, for example. They act as a client when they download files on their computer. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Client/Server Architecture
Chapter 6 Client/Server Architecture In a client-server network, any client connected to the server can access the programs and files that are stored there. While the client can make requests of the server, the server never makes requests from the client. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Peer-to-Peer Architecture
Chapter 6 Peer-to-Peer Architecture In a peer-to-peer network, every computer in the network can act as both client and server. Because any computer on the network can request services of any other computer, it’s difficult to support lots of traffic on the network. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Network Topologies Arrangement of devices in a network. Three kinds: Bus topology Ring topology Star topology Bullet 1: Network topology refers to how computers, servers, and other devices are arranged in a network. This is the physical layout of the devices, not a reflection of how data moves around the network. Bullet 2: The three most commonly used topologies are bus, ring, and star. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Bus Topology In a network using bus topology, all the devices are connected by one cable. The cable, called the bus, transmits data and the instructions required to deliver that data among all the computers in the network. If one device malfunctions, it has no effect on other devices on the bus cable. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ring Topology A network using ring topology connects devices, one after the other, in a closed loop. Data travels from one device to another until it gets to its destination. However, if one device on the ring fails, all the devices after it on the circuit can’t receive data. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Star Topology In a star topology all the devices on the network connect to a central device, typically a hub or a switch. Data can be passed to any other device on the network. If one device on the network fails, no other devices are affected. However, if the hub or switch fails, the entire network crashes. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 local area network (LAN) server wireless LAN (WLAN) metropolitan area network (MAN) wide area network (WAN) network architecture client/server network client The section 6.6 terms to know are: local area network (LAN): A type of network in which connected devices are located within the same room or building, or in a few nearby buildings. server: Any combination of hardware and software that provides a service, such as storing data, to a client, such as a computer. wireless LAN (WLAN): A local area network that uses wireless technology. metropolitan area network (MAN): A type of network that connects networks within a city or other populous area to a larger high-speed network; typically made up of several LANs that are managed by a network provider. wide area network (WAN): A type of network that serves larger geographic areas. WANs, such as the Internet, are used to share data between networks worldwide. WANs might use leased T1/T3 lines, satellite connections, radio waves, or a combination of communications media. network architecture: The design and layout of the communications system; how computers in a network share resources. client/server network: A network architecture in which a computer (called the server) stores programs and files that any connected device (called a client) can access. client: A computer or other device capable of sending data to and receiving data from a server on a network. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 distributed application architecture peer-to-peer (P2P) network Internet peer-to-peer (P2P) network topology bus topology ring topology star topology (Continued) distributed application architecture: A network architecture that distributes tasks between client computers and server computers. peer-to-peer (P2P) network: A network architecture in which each computer in the network can act as both server and client. Internet peer-to-peer (P2P) network: A modification of peer-to-peer used on the Internet to share files. topology: How devices in a network are physically arranged and connected to each other. bus topology: An arrangement where all the computers and other devices on a network, such as printers, are connected by a single cable. ring topology: An arrangement that has computers and other devices connected, one after the other, in a closed loop. Data transmitted on a ring network travels from one computer to the other until it reaches its destination. star topology: An arrangement in which all the devices on the network connect to a central device. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… Which type of network server is shown here? LAN. MAN. WLAN. WAN. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

6.6 Networking Devices and Software
Chapter 6 6.6 Networking Devices and Software Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Network Devices Network devices include: Modems. Network adapters. Wireless access points and routers. Repeaters. Hubs and switches. Gateways and bridges. Bullet 1: Anything that connects to a network is called a node. This includes scanners, printers, computers, as well as hardware that enables exchange of data among devices over a transmission medium, such as: Modems, which send and receive signals. A dial-up modem works with phone transmissions. A DSL modem works with phone transmissions, accepts digital signals, and filters out incoming voice signals. This means you can use your phone while your computer sends or receives transmissions. Cable modems connect via a high-speed cable network. A wireless modem is a PC card that you insert into a laptop or other device to pick up an Internet connection. Network adapters allow your computer to connect to a network. Two types of network adapters are network interface cards (abbreviated NIC) and wireless interface cards. In the most recent computers, NICs take the form of a circuit board built into the computer motherboard. Wireless access points and routers help devices on a network communicate with one another. A repeater is a device that takes a signal and retransmits it at a higher power level to boost the transmission strength. Hubs and switches have similar roles. They coordinate message traffic on a network. Compared to hubs, switches are a little more reliable in delivering messages to the correct destination. Finally, gateways and bridges help separate networks to communicate with each other. A gateway connects networks using different topologies. A bridge connects networks that use the same topology. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Network Devices These are examples of hardware that is needed by networks to connect and send data. A router is shown at the top left. The top right image is a switch. The bottom right image is a gateway. The bottom left image is a hub. © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Wireless Network Access Point
Chapter 6 Wireless Network Access Point A wireless access point contains a high-quality antenna. The antenna allows computers and mobile devices to transmit data or exchange data with a wired network, as you can see in this illustration. Each device must be equipped with a wireless adapter. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Networking Operating Systems
Chapter 6 Networking Operating Systems Used for managing networks. Installed on the central server. Bullet 1: A network needs special software to help it function. A network operating system (abbreviated NOS) adds features that help the administrator manage the network. Some popular network operating systems are Novell Netware and Microsoft Windows Server. Bullet 2: An NOS is installed on the central server along with other types of software that enable the network to run. The NOS includes programs that control the flow of data among client devices, control access to resources, and manage user accounts. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 node dial-up modem DSL modem cable modem wireless modem mobile broadband stick network adapter network interface card (NIC) wireless interface card The section 6.6 terms to know are: node: A device connected to a network. dial-up modem: A piece of hardware that works with telephone transmissions and changes or manipulates an analog signal so that it can be understood by a computer or fax machine which only understand digital signals. DSL modem: A piece of hardware that allows you to connect to your existing telephone system, but separates voice from data traffic so that you don’t lose the use of your telephone while your computer is transmitting or receiving data. DSL stands for digital subscriber line. cable modem: A piece of hardware that enables you to send and receive digital data using a high-speed cable network based on the cable television infrastructure found in many homes. mobile broadband stick: A USB device that acts as a modem to give users computer access to the Internet. wireless modem: A piece of hardware that typically takes the form of a PC card that you slot into a device to provide it with an antenna that can pick up a connection to the Internet. network adapter: A device that provides a computer with the ability to connect to a network. network interface card (or NIC): A type of network adapter card. In most current computers, NICs take the form of a circuit board built into the motherboard of a computer. It enables a client computer on a LAN to connect to a network by managing the transmission of data and instructions received from the server. wireless interface card: A network interface card that uses wireless technology. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 wireless access point router wireless router repeater hub switch gateway bridge network operating system (NOS) (Continued) wireless access point: A hardware device containing a high-quality antenna that allows computers and mobile devices to transmit data to each other or to exchange data with a wired network. router: A hardware device that connects two or more networks. wireless router: A hardware device that allows you to connect multiple networks using wireless communication signals. repeater: An electronic device that takes a signal and retransmits it at a higher power level to boost the transmission strength. A repeater can also transmit a signal to move past an obstruction, so that the signal can be sent further without degradation. hub: A device used on older LAN networks to coordinate the message traffic among nodes connected to a network. switch: A hardware device that joins several computers together to coordinate message traffic in one LAN network. Although a switch performs a role similar to a hub, a switch checks the data in the packets it receives and sends the packet to the correct destination using the fastest route. gateway: A device that helps separate but dissimilar networks to communicate with each other. bridge: A device that helps separate but similar networks to communicate with each other. network operating system (NOS): Programs that control the flow of data among clients, restrict access to resources, and manage individual user accounts. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… Each device connected to a network is called a(n) modem. node. interface card. access point. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Network Security Security on home or work networks is of great concern today. Attackers can steal information, change security settings, or disrupt operations. Network security can involve several techniques and technologies. Chapter 8 covers computer security in more detail. One technique shown in this illustration is a firewall. These software and hardware systems stop people outside of a network from sending information into the network or taking information out of it. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Computers in Your Career
Chapter 6 Computer security is a hot career. Growth is due to increases in cyber attacks and Internet-based applications. Bullet 1: Computer security is a hot field due to a constant barrage of security threats. Companies know that protecting their information and the records of their customers is vital to their success. Bullet 2: The Bureau of Labor Statistics Occupational Outlook Handbook for 2009 states that career opportunities in computer security are growing due to increases in Internet-based applications and cyber attacks. Next slide Computers in Your Career © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 firewall The section 6.7 term to know is: firewall: Software and hardware systems that stop people outside of a network from sending information into the network or taking information out of it. Next slide Terms to Know © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… A combination of hardware and software that stops people outside a network from sending information into it is called a network administrator. network security. a firewall. a firebreak. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

6.8 Interesting Trends in Networking
Chapter 6 6.8 Interesting Trends in Networking Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Mobility and VoIP Building Wi-Fi and VoIP into intranets. Saving money. Bullet 1: Many companies are building two hot technologies, Wi-Fi and VoIP (Voice over Internet Protocol), into their intranets. Employees can then use cell phones without dropping a call as they move around the company’s buildings or step outside. Bullet 2: VoIP saves companies money because it makes calls over the Internet, rather than across traditional phone lines with their associated costs. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Cloud Computing Software used from a network server. Cloud services are flexible. Bullet 1: Another hot networking trend is cloud computing, which was introduced in Chapter 5. Elements of a network that are kept invisible to users are considered to be in the cloud. Web 2.0 has taken that idea online. Now software as a service is hosted on a network server. This means users no longer install software on their computers. Bullet 2: A cloud service is a flexible way to use software. It offers three features that make it different from software located on your computer or network. First, services are sold on demand and billed by the minute or hour, so you only pay for what you use. Second, people can use as many of the service features they want. Finally, users never have to install, upgrade, or troubleshoot software because the provider maintains the service. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

Chapter 6 Ask Yourself… A new networking trend is that companies are building this cost-saving feature into their internal networks VoIP. network servers. firewalls. cell towers. Next slide © Paradigm Publishing, Inc. © Paradigm Publishing, Inc.

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