Chapter 8

Learning Objectives

• Explain connectivity, the wireless revolution, and communication systems
• Describe physical and wireless communications channels
• Differentiate between connection devices and services
• Describe data transmission factors, including bandwidth and protocols
• Define networks and key network terminology
• Describe different types of networks
• Describe network architectures, including topologies and strategies
• Explain organization issues related to Internet technologies and network security

Introduction

• We live in a truly connected society
• Increased connectivity potentially means increased productivity, especially in business
• Students will learn about connectivity and the impact of the wireless revolution

Communication

• Computer communications is the process of sharing data, programs, and information between two or more computers
• Numerous applications depend on communication systems, including texting, email, videoconferencing, and electronic commerce

Connectivity

• Connectivity uses computer networks to link people and resources
• Connects personal computers to other computers and resources on a network and the Internet
• Wireless revolution is the single most dramatic change in connectivity in the past decade
• Allows individuals to connect to the Internet and share information from almost anywhere in the world

Communication Systems

• Communication systems are electronic systems that transmit data from one location to another
• Wired or wireless, every communication system has four basic elements: sending device, message, connection device, communication channel, connection device, message, receiving device, and packets

Basic Elements of Communication

• Sending and receiving devices (computer or specialized communication device)
• Connection devices (interface between sending and receiving device)
• Data transmission specifications (rules and procedures that coordinate the devices)
• Communication channel (carries the message)

Communication Channels

• Physical connections using wire or cable
• Wireless connections

Wireless Connections

• Wireless connections do not use a solid substance to connect, primarily using radio waves
• Primary wireless technologies are cellular, Bluetooth, Wi-Fi, microwave, WiMax, and satellite connections
• Key Wi-Fi alliance and IEEE standards and their maximum data rates are provided in table format

Physical Connections

• Physical connection uses solid medium to connect between sending and receiving devices
• Twisted pair cable: two pairs of copper wire twisted together (telephone lines, Ethernet cables)
• Coaxial cable: single solid copper core (Cable TV)
• Fiber-optic cable: tiny glass tubes

Primary Wireless Technology

• Bluetooth (short-range) – radio communication standard
• Wi-Fi (wireless fidelity) – uses high-frequency radio waves
• Microwave – uses high-frequency radio waves
• WiMax (extends Wi-Fi) – new standard that extends Wi-Fi range using microwave
• Cellular – use multiple antennae for communication
• Satellite – uses satellites as microwave relay stations
• Infrared - Uses infrared light for communication over short distances
• GPS – determines geographic location of devices

Connection Device Signals

• Types of signals (analog, digital)
• Transfer rates (Mbps – million bits per second, Gbps – billion bits per second, Tbps – trillion bits per second)

Connection Devices

• Modem – modulator-demodulator
• Modulation – converting digital to analog
• Demodulation – converting analog to digital
• Transfer rate – speed of data transfer, usually measured in megabits per second (Mbps)

Types of Modems

• Digital Subscriber Line (DSL) – high-speed telephone lines
• Cable – uses coaxial cable
• Wireless – also known as WWAN

Connection Services

• Leased lines (T1 combined to form T3 and DS3, replaced by OC lines, faster optical carrier lines, higher capacity, not affordable for individuals)
• DSL (uses phone lines, increasingly ADSL most commonly used)
• Cable (uses existing TV cable, faster than DSL)
• Other Connection Services

Network Types

• LAN (Local Area Network) - located within close proximity
• Home - Local area network for home use, usually wireless (WLAN)
• Wireless Local Area Network (WLAN) - wireless local area network, communication passes through an access point
• Personal Area Network (PAN) - connects digital devices
• Metropolitan Area Network (MAN) - typically spans cities, coverage up to 100 miles
• Wide Area Network (WAN) - countrywide or worldwide coverage

Network Architecture

• How the network is arranged and resources are shared
• Network Topology – physical arrangement of the network
• Network Strategy – How the information and resources are shared
• Key network topologies including ring, star, tree, and mesh

Network Strategies

• Client/Server Network – Central computers coordinate and supply services, server provides access, client requests services, typical server OS ex. Windows Server, macOS X Server, Linux, and Solaris
• Peer-to-Peer (P2P) Network – All nodes have equal authority, can act both as client and server

Organizational Networks

• Intranet – private network within an organization, works like the internet
• Extranet – private network that connects more than one organization, works like internet with limited access for trusted partners

Network Security

• Firewall – hardware/software controls access to a network
• Proxy server – provides pass-through access, protects against external threats
• Intrusion Detection System (IDS) – Works with firewall to protect organization's network, analyzes incoming/outgoing network traffic
• Virtual Private Network (VPN) – creates secure private network between user computer and the organization

Network Security Graphic

• Diagram of intranet, extranet, and proxy servers

Careers in IT

• Network Administrator – manages company's LAN and WAN networks, responsible for design, implementation, and maintenance; maintains networking hardware/software, must diagnose and repair problems, candidates typically have Bachelor's/Associate's degree in computer science, computing technology, or information systems, experience with network security is preferred, certification and good communication skills are preferred

A Look to the Future

• Telepresence – seeks to create the illusion of being at a remote location, early implementations focus on an extension of video-conferencing, will allow to touch things in a remote location through robotics

Open-Ended Questions

• Define communications (connectivity, wireless revolution, communication systems)
• Discuss communication channels (physical and wireless connections)
• Discuss connection devices (modems, etc) and connection services
• Discuss data transmission (bandwidths, protocols, IP addresses, etc)
• Discuss networks (terms, types)
• Define network architecture (topologies, strategies)
• Discuss organization networks (intranets, extranets, security)

This quiz explores key concepts of connectivity and communication systems in our increasingly connected world. Students will delve into physical and wireless communication channels, network architectures, and the factors influencing data transmission. Test your understanding of network terminology and security issues related to Internet technologies.