Chapter 6 Communication and Networks PDF

Communications and Networks CHAPTER 6 Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Discusscom...

Communications and Networks CHAPTER 6 Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Discusscommunication systems. ▪ Describe physical and wireless communications channels. ▪ Discussconnection devices and services, including dial-up, DSL, cable, satellite, and cellular. ▪ Describe data transmission factors, including bandwidth and protocols. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Describe different types of networks, including local, personal, metropolitan, and wide area networks. ▪ Describe network architectures, including topologies and strategies. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Communications : Sending and receiving information from one point to another point. ▪ Computer communications is the process of sharing data, programs, and information between two or more computers over the network. ▪ Numerous applications depend on communication systems, including ▪ E-mail ▪ Texting ▪ Banking ▪ Video Conferencing ▪ Electronic commerce Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Connects your personal computer to other computers and resources on a network and the Internet. ▪ TheWireless Revolution ▪ Allows connectivity with anyone from almost anywhere at any time ▪ Wireless technology allows a wide variety of nearby devices to communicate with one another without any physical connection. (wireless mouse, wireless keyboard, etc.) ▪ Wireless communications allows to share high speed printer, share data files, and collaborate on working documents. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Electronic systems that transmit data from one location to another Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Four basic elements: ▪ Sending and receiving devices ▪ The computer send and receive messages in the form of data, information or instructions. ▪ Connection devices ▪ Interface between sending and receiving device and communication channel. ▪ Convert outgoing messages into packets that can travel across the communication channel. ▪ Also reverse the process for incoming messages. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Four basic elements: ▪ Data transmission specifications ▪ Rules and procedures that coordinate the sending and receiving devices. ▪ Define how the message will be sent across the communication channel. ▪ Communication channel ▪ Actual connecting or transmission medium that carries the message. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Communication channels carry the data from one computer to another ▪ Two categories of communication channels ▪ Physical Connections ▪ Wireless Connections Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Use a solid medium to connect sending and receiving devices. Examples: ▪ Twisted-pair cable ▪ Coaxial cable ▪ Fiber-optic cable Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Twisted pair cable – consists of pairs of copper wire that are twisted together ▪ Telephone lines ▪ Ethernet cables ▪ Coaxial cable – a high frequency transmission cable with a single solid copper core (80 times the transmission capacity of twisted pair). ▪ Cable TV ▪ Fiber-optic cable – transmits data as pulses of light through tiny tubes of glass ▪ Lighter, faster and more reliable at transmitting data than coaxial cable Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Wireless connections do not use a solid substance to connect; uses the air itself. Most use radio waves to communicate. Examples: ✓ Cell phones Technologies used for wireless connections: ✓ Cellular ✓ Bluetooth ✓ Infrared ✓ Wi-Fi ✓ Satellite connections Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Cellular : ▪ use multiple antennae to send and receive data within relatively small geographic area. ▪ Examples: Smart Phone Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Bluetooth : ▪ short range radio communication standard that transmits data over short distances of up to approximately 33 feet. ▪ Examples: Wireless headphone, wireless mouse, wireless keyboard, etc. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Infrared : ▪ use infrared light waves to communicate over short distances. ▪ Only can travel in a straight line. ▪ Sending and receiving devices must be in clear view of one another without any obstructions blocking that view. ▪ Examples: TV remote control. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks WIFI : ▪ Uses high frequency radio signals to transmit data. ▪ Examples: Home and business wireless network. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Satellite connection : ▪ Can amplify and relay microwave signals from one transmitter on the ground to another. ▪ Examples: GPS. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Types of signals ✓ Analog ✓ Digital ▪ Telephone line were designed to carry analogsignal. ▪ Computer –send and receive digital signals (1s and 0s). ▪ Modem device needed to convert digital signal to analog and vice versa. ▪ This speed, called Transfer rate is usually measured in Mbps. ▪ The higher the speed, the faster you can send and receive information. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Modem : modulator – demodulator ▪ Modulation is the process of converting from digital to analog ▪ Demodulation is the process of converting from analog to digital ▪ The modem enables digital personal computer to communicate across different media, includes telephone wire, cable line, and radio waves. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Types of modems: ▪ DSL(digital subscriber line) ▪ Cable modem ▪ Wireless modem Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Types of modems ▪ DSL(digital subscriber line): ✓ Use standard phone lines to create a high-speed connection. ✓ These devices are external and connect to the system using either USB or Ethernet port. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Types of modems ▪ Cable modem: ✓ Use the same coaxial cable as television. ✓ Same as DSL modem which creates high-speed connection using the system unit USB or Ethernet port. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Types of modems ▪ Wireless modem: ✓ Known as WMAN (Wireless wide area network) modem. ✓ Almost all computers today have built in wireless modems. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Cellular ServicesProvider: ✓ G stands for GPRS (General Packet Radio Service). - When you see G near your signal strength indicator, it is certain that your net connection is working at the slowest speed. ✓ E stands for EDGE (Enhanced Data Rates for GSM Evolution). - EDGE is faster than GPRS but still not good enough to browse the Internet. ✓ 3G means the third generation of mobile telephone technology. - 3G is faster than EDGE and you can easily browse websites and stream music. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Cellular ServicesProvider: ✓ 4G is the fourth generation of mobile technology. If you see 4G near the signal bar in your mobile phone, you’re lucky! It means you now have fast mobile internet connection ✓ 5G is the fifth generation of mobile technology. More luckier, you’re using the fastest mobile Internet connection available on the globe at present. improved wireless network technologies deploying improve download speeds even more and might also save the average Brit big money. meet the needs of new use-cases such as the Internet of Things Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Measurement of the width or capacity of the communication channel. ▪ Bandwidth is how much information can move across the communication channel in a given amount of time. ▪ Categories of bandwidth: ▪ Voice band (or low bandwidth) – used for standard telephone communication ▪ Medium band – used for midrange and mainframe computer (Transmit data over long distances). ▪ Broadband – widely used for DSL, cable, satellite connections (high speed data transfer). ▪ Baseband – to connect personal computers that are located close to one another (carry one signal at one time). Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Communication rules for exchanging data between computers ▪ HTTPS – Hypertext Transfer Protocol secure ✓ Widely used to protect the transfer of sensitive data. ▪ Internet standard: TCP/IP (Transmission control protocol/Internet protocol). ▪ The essential features of this protocol: (1) identifying sending and receiving devices (2) breaking information into small parts, or packets, for transmission across the Internet. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks i. Identification – Each computer is identified with unique IP (Internet Protocol) address. The user enter a URL, then a DNS converts this to an IP address before a connection can be made. DNS (Domain name server) : converts text-based address to IP address. The Internet uses IP addresses to deliver and to locate websites. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ii. Packetization : Refer to Information sent or transmitted across the Internet usually travels through numerous interconnected networks. Before the message is sent, It is broken down into small parts called packet Each packet is then sent separately over the Internet At the receiving end, the packets are reassembled into the correct order Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ A communication system that connects two or more computers. ▪ Allows exchange of information and resources. ▪ Networks can be set up in different arrangement to suit user’ needs. ▪ Network can be controlled by all nodes working together equally or by specialized nodes coordinating and supplying all resources. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Node – any device that is connected to a network ▪ Client – a node that requests and uses resources available ▪ Server – a node that shares resources with other ▪ Directory server – a specialized server that manage resources ▪ Host – any computer system connected to a network that provides access to its resources ▪ Router –node that forwards or routes data packets ▪ Switch – central node that coordinates the flow of data by sending messages directly between sender and receiver nodes ▪ Network interface cards (NIC) – expansion cards ▪ Network operating systems (NOS) – control and coordinate on a network ▪ Network administrator – responsible for network operation Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Wired or wireless allow different kinds of networks to be formed. Networks also may be citywide and even international, using both cable and wireless connections. Depends on the size of the geographic area. FOUR NETWORK TYPES: ▪ Personal area network (PAN) ▪ Local area network(LAN) ▪ Metropolitan area network (MAN) ▪ Wide area network (WAN) Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Personal Area Network (PAN) Works within a very small area—your immediate surroundings. Connect cell phones to headsets, keyboards to cell phones, and so on. The most popular PAN technology is Bluetooth, with a maximum range of around 33 feet. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Local Area Network (LAN) Networks with nodes that are in close physical proximity—within the same or two building. LANs span distances less than a mile and are owned and operated by individual organizations. widely used by colleges, universities, and other types of organizations to link personal computers and to share printers and other resources. The most common standard is known as Ethernet. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Metropolitan Area Network (MAN) Coverage is about 1km and less than 10 km. These networks are frequently used as links between office buildings that are located throughout a city. A network within large town or city. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Wide Area Network (WAN) Cover large geographic area. Countrywide and worldwide networks. These networks provide access to regional service (MAN) providers and typically span distances greater than 10 km. Use satellites to reach users over long distances—for example, from Los Angeles to Paris. Example: Internet. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Use a home network to share files, printers and to allow multiple users access to the Internet at the same time Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Network architecture describes how a network is arranged and how resources are coordinated and shared. ▪ It encompasses a variety of different network specifics, including network topologies and strategies. ▪ Network Topology: Physical arrangement of the network. A network can be arranged in several different ways. ✓ Bus Network ✓ Ring Network ✓ Star Network ✓ Tree Network ✓ Mesh Network ✓ Hybrid Network Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Network Strategies: How information and resources are shared. Every network has a strategy or ways of coordinating the sharing of information and resources. ✓ Client Server Network ✓ Peer-to-Peer Network Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Bus Network ▪ Connected to common cable called a bus or backbone. ▪ All communications travel along this bus. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Bus Network ▪ Advantages: ✓ Simplicity and low cost. ▪ Disadvantages: ✓ If the cable is damaged, the entire network will be down. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Ring Network ▪ Connected to two other devices, forming a ring. ▪ When message is sent, it is passed around the ring until it reaches the intended destination. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Ring Network ▪ Advantages: ✓ Efficiency, as it allows for fast data transfer. ▪ Disadvantages: ✓ If one cable fails, the entire network will be down. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Each device connected directly to a central network switch. ▪ Whenever a node sends a message, it is routed to the switch, which then passes the message along to the intended recipient. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Advantages: ✓ If one cable fails, the other devices will still be operational. ▪ Disadvantages: ✓ Its cost, as it requires more cabling and a central device. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Each device connected to a central node either directly or through subordinate nodes. ▪ The central node is connected to two or more subordinate nodes that in turn are connected to other subordinate nodes, and so forth, forming a treelike structure. ▪ Also called hierarchical network. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Advantages: ✓ Its scalability, as it can support a large number of devices. ▪ Disadvantages: ✓ Its complexity, as it requires more cabling and a central device. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Does not usea specific physical layout, but requires that each node have more than one connection to other nodes. ▪ If a path between two nodes is somehow disrupted, data can be automatically rerouted around the failure using another path. ▪ Wireless technologies are frequently used. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Advantages: ✓ Allows for multiple paths for data transfer. ▪ Disadvantages: ✓ Its cost, as it requires more cabling and more devices. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Hybrid Network Combination of two or more networks. The network type could be star, ring, bus, or mesh. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Hybrid Network ▪ Advantages: ✓ Its flexibility, as it can be customized to suit the specific requirements of a network. ▪ Disadvantages: ✓ Its complexity, as it requires more cabling and more devices. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Central computers coordinate and supply services to other nodes on the network ▪ Server provides access to Web pages, databases, application software, and hardware ▪ Server nodes coordinate and supply specialized services, and client nodes request the services. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ The computer (client) sends out a request for a specific web page. Then, this server locates and sends the requested material back to your computer. ▪ Advantages: ✓ Ability to handle very large networks efficiently. ✓ The availability of powerful network management software to monitor and control network activities. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Nodes have equal authority and can act as both clients and servers. ▪ To share information with others around the world. ▪ Examples: ✓ to share games, movies, and music over the Internet. ✓ File sharing software suchas BitTorrent used to share files with other microcomputers Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Advantages:Easyand inexpensive to set up Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Internet technologies support effective communication within and between organizations using Intranet and Extranet. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Intranet ▪ Private network within an organization that resembles the internet. ▪ Works like the Internet, where employees use browsers to access Web sites and Web pages. ▪ Use internet for information gathering and distributions within an organization, ▪ Examples: email address, internal job openings, employee benefit information, etc. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Extranet ▪ Private network that connects more than one organizations. ▪ It is for outside authorized users using the same internet technology. ▪ Works like the Internet, but provides suppliers and other trusted partners with limited access to the organization’s networks. ▪ Enable outsiders to work together with company’s employees. ▪ Purpose: To increase efficiency and reduce costs. ▪ Example: The automobile manufacturer has hundreds of suppliers for car parts. The supplier can access to the car production schedules and deliver parts as they are needed. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Commonly used technologies to ensure network security using Firewall, Intrusion detection system (IDS), and Virtual private network (VPN). ▪ Firewall : ▪ Hardware and software controls accessto network ▪ Proxy server provides pass-through access ▪ All communications between the company’s internal networks and the outside world pass through this server. ▪ the proxy server decides whether it is safe to let a particular message or file pass into or out of the organization’s network. ▪ Protects against external threats Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Restricted unknown traffic or access denied Traffic allowed Traffic allowed Filter communication between your network and outside networks Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Intrusion detection system (IDS): ▪ Works with firewall to protect organization's network ▪ Analyzes all incoming and outgoing network traffic. ▪ An IDS can recognize signs of a network attack and disable access before an intruder can do damage. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Virtual private network (VPN): ▪ Creates a secure private network connection between a remote computer and the organization’s internal network. ▪ Special VPN protocols create the equivalent of a dedicated line between a user’s home or laptop computer and a company server. ▪ The connection is heavily encrypted, and, from the perspective of the user, it appears that the workstation is actually located on the corporate network. Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks ▪ Virtual private network (VPN): Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.  Communications and Networks TOPIC REFLECTION 1) What is FOUR (4) basic elements for communication system? 2) Explain FOUR (4) network types. 3) Draw network topologies. 4) Describe each characteristics as well as advantages and disadvantages. 5) Differentiate between network topologies and network strategies. 6) Explain TWO (2) types of network strategies. THANK YOU Computing Essentials 2013 © 2013 TheMcGraw-Hill Companies, Inc. All rights reserved.