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Computer Concepts
Ch. 08 Communications and Networks
Question | Answer |
---|---|
1G (first-generation mobile telecommunications) | started in the 1980s using analog radio signals to provide analog voice transmission service. |
2G (second-generation mobile telecommunications) | started in the 1990s using digital radio signals. |
3G (third-generation mobile telecommunications) | started in the 2000s and provided services capable of effective connectivity to the Internet, marking the beginning of smartphones. |
4G (fourth-generation mobile telecommunications) | has begun to replace 3G networks in some areas with providers using LTE (Long Term Evolution) connections to provide faster transmission speeds. |
analog signal | are continuous electronic waves |
asymmetric digital subscriber line (ADSL) | is one of the most widely used types of DSL. DSL is much faster than dial-up. |
backbone or bus | all communications in a bus network travel along this bus. |
bandwidth | is a measurement of the width or capacity of the communication channel. Effectively, it means how much information can move across the communication channel in a given amount of time |
baseband | is widely used to connect individual computers that are located close to one another. Like broadband, it is able to support high-speed transmission. |
Bluetooth | is a short-range radio communication standard that transmits data over short distances of up to approximately 33 feet. |
broadband | is widely used for DSL, cable, and satellite connections to the Internet. Several users can simultaneously use a single broadband connection for high speed data transfer. |
bus network | —each device is connected to a common cable called a bus or backbone, and all communications travel along this bus. |
cable modem | uses the same coaxial cable as your television. Like a DSL modem, a cable modem creates high-speed connections using the system unit’s USB or Ethernet port. |
cable service | is provided by cable television companies using their existing television cables. These connections are usually faster than DSL. |
cellular | communication uses multiple antennae (cell towers) to send and receive data within relatively small geographic regions (cells). |
cellular service provider | , including Verizon, AT&T, Sprint, and T-Mobile, support voice and data transmission to wireless devices using cellular networks. These networks have gone through different generations. |
cell | small geographic regions |
cell tower | multiple antennaes |
client | a node that requests and uses resources available from other nodes. Typically, a client is a user’s personal computer. |
client/server network | use central servers to coordinate and supply services to other nodes on the network. The server provides access to resources such as web pages, databases, application software, and hardware. |
coaxial cable | a high-frequency transmission cable, replaces the multiple wires of telephone lines with a single solid-copper core. |
communication channel | This is the actual connecting or transmission medium that carries the message. This medium can be a physical wire or cable, or it can be wireless. |
communication system | are electronic systems that transmit data from one location to another. Whether wired or wireless, every communication system has four basic elements. |
computer network | is a communication system that connects two or more computers so that they can exchange information and share resources. |
connectivity | is a concept related to using computer networks to link people and resources. |
demodulation | is the process of converting from analog to digital. |
dial-up service | using existing telephones and telephone modems to connect to the Internet. This type of service has been replaced by higher-speed connection services including DSL, cable, satellite, and cellular services. |
digital signal | Computers send and receive |
digital subscriber line (DSL) | modem uses standard phone lines to create a high-speed connection directly to your phone company’s offices. These devices are usually external and connect to the system unit using either a USB or an Ethernet port. |
digital subscriber line (DSL) service | is provided by telephone companies using existing telephone lines to provide high-speed connections. |
directory server | a specialized server that manages resources, such as user accounts, for an entire network. |
domain name server (DNS) | converts text-based addresses to IP addresses. For example, whenever you enter a URL, say www.mhhe.com, _ converts this to an IP address before a connection can be made. |
downlink | refers to receiving data from a satellite |
Ethernet | most common standard; There are a variety of different standards or ways in which nodes can be connected to one another and ways in which their communications are controlled in a LAN. |
Ethernet cable | Use twisted pairs |
extranet | is a private network that connects more than one organization. Many organizations use Internet technologies to allow suppliers and others limited access to their networks. |
fiber-optic cable | transmits data as pulses of light through tiny tubes of glass. |
fiber-optic service (FiOS) | is showing up in some areas, but it is a new technology and not widely available. Current providers of FiOS include Google and Verizon with speeds faster than cable or DSL connections. |
firewall | consists of hardware and software that control access to a company’s intranet and other internal networks. |
global positioning system (GPS) | devices use that information to uniquely determine the geographic location of the device |
hierarchical network | 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. |
home network | allow different computers to share resources, including a common Internet connection. |
host | any computer system connected to a network that provides access to its resources. |
hotspot | Wireless access points that provide Internet access are widely available in public places such as coffee shops, libraries, bookstores, colleges, and universities. |
(hypertext transfer protocol secure) | is widely used to protect the transfer of sensitive information. |
hub | previously filled this purpose for a swicth by sending a received message to all connected nodes, rather than just the intended node. |
infrared | uses infrared light waves to communicate over short distances. Like microwave transmissions, infrared is a line-of-sight communication. |
intranet | is a private network within an organization that resembles the Internet. Like the public Internet, intranets use browsers, websites, and web pages. |
intrusion detection system (IDS) | work with firewalls to protect an organization’s network. |
IP address (Internet protocol address) | Every computer on the Internet has a unique numeric address |
local area network (LAN) | Networks with nodes that are in close physical proximity—within the same building |
LTE (Long Term Evolution) | connections to provide faster transmission speeds |
medium band | is used in special leased lines to connect midrange computers and mainframes as well as to transmit data over long distances. |
megabits per second (Mbps) | millions of bits |
mesh network | this topology is the newest type and does not use a specific physical layout (such as a star or a tree). Rather, the mesh network requires that each node have more than one connection to the other nodes. |
metropolitan area network (MAN) | span distances up to 100 miles. These networks are frequently used as links between office buildings that are located throughout a city. |
microwave | communication uses high-frequency radio waves. It is sometimes referred to as line-of-sight communication because microwaves can only travel in a straight line. |
modem | is short for modulator-demodulator. |
modulation | is the name of the process of converting from digital to analog |
network administrator | a computer specialist responsible for efficient network operations and implementation of new networks. |
network architecture | describes how a network is arranged and how resources are coordinated and shared. |
network gateway | is a device that allows one LAN to be linked to other LANs or to larger networks. For example, the LAN of one office group may be connected to the LAN of another office group. |
network interface card (NIC) | these are expansion cards located within the system unit that connect the computer to a network. Sometimes referred to as a LAN adapter. |
network operating system (NOS) | control and coordinate the activities of all computers and other devices on a network. These activities include electronic communication and the sharing of information and resources. |
node | any device that is connected to a network. It could be a computer, printer, or data storage device. |
optical carrier (OC) | T1 lines and T3 line have been mostly replaced by |
packet | Before the message is sent, it is reformatted or broken down into small parts |
peer-to-peer (P2P) network | nodes have equal authority and can act as both clients and servers. The most common way to share games, movies, and music |
personal area network (PAN) | is a type of wireless network that works within a very small area—your immediate surroundings. |
protocol | rules for exchanging data between computers are known as |
proxy server | All communications between the company’s internal networks and the outside world pass through this server. |
ring network | each device is connected to two other devices, forming a ring. |
router | a node that forwards or routes data packets from one network to their destination in another network. |
satellite | communication uses satellites orbiting about 22,000 miles above the earth as microwave relay stations |
satellite connection service | use satellites to provide wireless connections. While slower than DSL and cable modem, satellite connections are available almost anywhere using a satellite-receiving disk. |
server | a node that shares resources with other nodes. Dedicated servers specialize in performing specific tasks. Depending on the task may be called an application server, communication server, database server, file server, printer server, or web server. |
star network | each device is connected directly to a central network switch. |
strategy | way of coordinating the sharing of information and resources. Two of the most common network strategies are client/server and peer-to-peer. |
switch | central node that coordinates the flow of data by sending messages directly between sender and receiver nodes. |
T1 | large corporations have been leasing special high-speed lines from telephone companies. Originally, these were copper lines |
T3 | large corporations have been leasing special high-speed lines from telephone companies. Originally, these were copper lines, known as T1 lines, that could be combined to form higher-capacity options, also known as DS3 |
telephone line | Use twisted pairs |
topology | A network can be arranged or configured in several different ways |
transfer rate | The speed with which modems transmit data varies. This speed is typically measured in millions of bits (megabits) per second (Mbps). |
transmission control protocol/Internet protocol (TCP/IP) | like is another widely used Internet protocol |
tree network | each device is connected to a central node, either directly or through one or more other devices. |
twisted-pair cable | consists of pairs of copper wire that are twisted together. Both standard telephone lines and Ethernet cables use |
uplink | is a term relating to sending data to a satellite. |
virtual private network (VPN) | create a secure private connection between a remote user and an organization’s internal network. |
voiceband | also known as low bandwidth, is used for standard telephone communication. Personal computers with telephone modems and dial-up service use this bandwidth, also known as low bandwidth. |
wide area network (WAN) | are countrywide and worldwide networks. These networks provide access to regional service (MAN) providers and typically span distances greater than 100 miles. They use microwave relays and satellites to reach users over long distances |
Wi-Fi (wireless fidelity) | uses high-frequency radio signals to transmit data. |
WiMax (Worldwide Interoperability for Microwave Access) | is a new standard that extends the range of Wi-Fi networks using microwave connections. |
wireless access point | All communications in a wireless LAN passes through the network’s centrally located, also known as base station. |
wireless LAN (WLAN) | uses radio frequencies to connect computers and other devices. |
wireless modem | also known as a WWAN (wireless wide area network) modem. Almost all computers today have built-in wireless modems. For those that do not, wireless adapter cards are available that plug into USB or special card ports. |