Computer Networks Chapter 9

Chapter Nine: Communications and Networks

• Computer communications is the process where two or more computers or devices exchange data, instructions, and information.
• Sending devices, communication channels, and receiving devices are involved in this process.
• Successful communications require specific components that can successfully identify various sending and receiving devices.
• Networks offer advantages: facilitating communications, sharing hardware, sharing data and information, sharing software, and transferring funds.
• Networks are categorized into: Local Area Networks (LANs), Metropolitan Area Networks (MANs), and Wide Area Networks (WANs). LANs connect computers and devices within a limited geographical area. MANs connect multiple LANs within a metropolitan area. WANs span large geographical areas.
• Client/server networks have dedicated servers that provide resources and services to client computers. Peer-to-peer networks allow any computer to act as both a client and a server, sharing resources directly with other computers.
• Network topologies describe the layout of the network. Common network topologies include: star, bus, and ring.
• Another term is network architecture, the design of computers, devices, and media connected to a network.
• Different communication standards, such as Ethernet, Token Ring, TCP/IP, Wi-Fi, Bluetooth, UWB, IrDA, RFID, WiMAX, and WAP are used in networks to exchange data.
• Wi-Fi uses the 802.11 standard that facilitates wireless communication.
• Groupware helps groups cooperate on projects, sharing information over a network.
• Wireless message services enable users to send and receive messages wirelessly using picture messages, video messages, and text messages.
• Examples of how they work include wireless Internet access points which connect wirelessly to the Internet.
• Cybercafés provide public access to personal computers with internet access.
• GPS systems determine a GPS receiver's location using signals from satellites.
• Communications software is used to establish connections between computers and networks, manage data transmission, and assist with communication between users across the network.
• The PSTN is a worldwide telephone system using physical transmission media like twisted-pair cables, coaxial cables, and fiber-optic cables to exchange data.
• Various types of internet connections like dial-up, ISDN, DSL, FTTP and ATM can be found in the telephone network.
• Data transmission speeds vary based on the type of internet connection.
• Communications devices include modems, network cards, wireless access points, and routers. They enable data transmission between computers, devices, and networks.
• A wireless modem employs a cell phone network to link devices to the internet for wireless connection to the network.
• Network cards enable computers to access a network. Wireless network cards often use antennas for their connections.
• A wireless access point is a communications device allowing wireless data transfer.
• A router is a hardware device that connects multiple computers on a network and transmits data to its correct destination.
• Hubs or switches connect several devices within a network.

Types of Home Networks

• Wired home networks include Ethernet, powerline cable, and phoneline.
• Wireless home networks employ various wireless transmission media such as infrared, Bluetooth, or Wi-Fi.

How to Set Up a Home Network (Steps)

• Sign up for high-speed internet service.
• Connect the network card to the router/wireless access point.
• Connect the router/wireless access point to the cable/DSL modem.
• Install the wireless network card or adapter on other desktop computers.
• Insert a wireless USB network adapter, ExpressCard module, or PC Card into each notebook computer.

Communications Channel

• Bandwidth refers to the amount of information that can travel over a communication channel.
• Latency is the delay time for a signal to travel from one location to another on a network.
• Transmission media carries one or more signals for data transmission.
• Broadband media allows the simultaneous transmission of multiple signals.

Physical Transmission Media

• Examples include twisted-pair cables, coaxial cables, and fiber-optic cables.

Wireless Transmission Media

• Wireless transmission media like infrared transmissions, Bluetooth, and UWB (ultra-wideband) allow wireless communication at high speeds.
• Cellular radio uses multiple base stations to transmit data widely for mobile communication.
• Microwave uses microwave stations that transmit data quickly across distances.
• A communications satellite receives microwave signals from an Earth-based station, amplifies them, and broadcasts the amplified signal across a broad area.

Summary

• Overview of communication terminology and applications along with how networked computers combine.
• Details of the various communication devices, media, and network procedures.