6. Data Communication Flashcards
Data communication
Electronic transfer of data from one location to another
Bandwidth
Amount of data that can be transferred from one point to another in a certain time period, usually a second.
Attenuation
Loss of power in a signal as it travels from the sending device to receiving device
Broadband
Multiple pieces of data are sent simultaneously to increase transmission rate
Protocols
Rules that govern aspects of data communication including error detection, message length, and transmission speed
Modem
A device that connects a user to the internet
Centralized processing
All processing is done at one central computer
Communication media
Or channels, connect sender and receiver devices. Can be conducted or radiated
Conducted media
Provides a physical path along which signals are transmitted
Radiated media
Use an antenna for transmitting data through air or water
Decentralized processing
Where each user or dept has its own computer for processing tasks
Narrowband
is a voice-grade transmission channel capable of transmitting a maximum of 56,000 bps, so only a limited amount of information can be transferred in a specific period of time.
Digital subscriber line (DSL)
a common carrier service, is a high-speed service that uses ordinary phone lines.
Distributed processing
maintains centralized control and decentralized operations. Processing power is distributed among several locations.
local area network (LAN)
A local area network (LAN) connects workstations and peripheral devices that are in close proximity.
Open Systems Interconnection (OSI) model
The Open Systems Interconnection (OSI) model is a seven-layer architecture for defining how data is transmitted from computer to computer in a network, from the physical connection to the network to the applications that users run. It also standardizes interactions between network computers exchanging information.
metropolitan area network (MAN)
A metropolitan area network (MAN) is designed to handle data communication for multiple organizations in a city and sometimes nearby cities as well.
wide area network (WAN)
A wide area network (WAN) can span several cities, states, or even countries, and is usually owned by several different parties.
network interface card (NIC)
A network interface card (NIC) is a hardware component that enables computers to communicate over a network.
network topology
A network topology represents a network’s physical layout, including the arrangement of computers and cables.
controller
A controller is a hardware and software device that controls data transfer from a computer to a peripheral device (for example, a monitor, a printer, or a keyboard) and vice versa.
star topology
The star topology usually consists of a central computer (the host computer, often a server) and a series of nodes (typically, workstations or peripheral devices).
hierarchical topology
A hierarchical topology (also called a “tree”) combines computers with different processing strengths in different organizational levels.
bus topology
The bus topology (also called “linear bus”) connects nodes along a network segment, but the ends of the cable are not connected, as they are in a ring topology.
ring topology
In a ring topology, no host computer is required because each computer manages its own connectivity.
multiplexer
A multiplexer is a hardware device that allows several nodes to share one communication channel.
mesh topology
In a mesh topology (also called “plex” or “interconnected”), every node is connected to every other node.
packet
A packet is a collection of binary digits—including message data and control characters for formatting and transmitting—sent from computer to computer over a network.
routing
is the process of deciding which path to take on a network. This is determined by the type of network and the software used to transmit data.
Transmission Control Protocol/Internet Protocol (TCP/IP)
is an industry-standard suite of communication protocols that enables interoperability.
routing table
A routing table, generated automatically by software, is used to determine the best possible route for a packet.
centralized routing
In centralized routing, one node is in charge of selecting the path for all packets. This node, considered the network routing manager, stores the routing table, and any changes to a route must be made at this node.
router
A router is a network connection device containing software that connects network systems and controls traffic flow between them.
Distributed routing
relies on each node to calculate its own best possible route. Each node contains its own routing table with current information on the status of adjacent nodes so packets can follow the best possible route.
Static routes
are manually configured and give the router information about available networks in the form of IP addresses. Static routes are ideal for smaller networks.
Dynamic routes
are learned dynamically (automatically) and added to the routing table using a dynamic routing protocol such as RIP (Routing Information Protocol) or OSPF (Open Shortest Path First); they are ideal for larger networks.
wireless network
A wireless network uses wireless instead of wired technology.
n-tier architecture
An n-tier architecture attempts to balance the workload between client and server by removing application processing from both the client and server and placing it on a middle-tier server.
client/server model
In the client/server model, software runs on the local computer (the client) and communicates with the remote server to request information or services. A server is a remote computer on the network that provides information or services in response to client requests.
two-tier architecture
In the two-tier architecture, the most common type, a client (tier one) communicates directly with the server (tier two).
mobile network
A mobile network (also called a cellular network) operates on a radio frequency (RF) and consists of radio cells, each served by a fixed transmitter known as a cell site or base station.
Worldwide Interoperability for Microwave Access (WiMAX)
is a broadband wireless technology based on the IEEE 802.16 standards. It is designed for wireless metropolitan area networks and usually has a range of about 30 miles for fixed stations and 3–10 miles for mobile stations.
Wi-Fi
is a broadband wireless technology. Information can be transmitted over short distances—typically 150 feet indoors and 300 feet outdoors—in the form of radio waves.
Bluetooth
which can be used to create a personal area network (PAN), is a wireless technology for transferring data over short distances (usually 800 feet, or 240 meters) using fixed and mobile devices.
Time Division Multiple Access (TDMA)
To improve the efficiency and quality of digital communications, Time Division Multiple Access (TDMA) divides each channel into six time slots. Each user is allocated two slots: one for transmission and one for reception. This method increases efficiency by 300 percent, as it allows carrying three calls on one channel.
Throughput
is similar to bandwidth. It is the amount of data transferred or processed in a specified time, usually one second.
Code Division Multiple Access (CDMA)
To improve the efficiency and quality of digital communications, Code Division Multiple Access (CDMA) transmits multiple encoded messages over a wide frequency and then decodes them at the receiving end.
Wireless Fidelity (Wi-Fi)
is a broadband wireless technology. Information can be transmitted over short distances—typically 150 feet indoors and 300 feet outdoors—in the form of radio waves.
convergence
In data communication, convergence refers to integrating voice, video, and data so that multimedia information can be used for decision making.
