Definitions Flashcards
DHCP
The Dynamic Host Configuration Protocol is a network management protocol used on Internet Protocol networks for automatically assigning IP addresses and other communication parameters to devices connected to the network using a client–server architecture.
67 68
DNS
Domain Name System (DNS) An Application-layer protocol that resolves computer and domain names to their IP addresses; it uses UDP port 53.
WAP
access point (AP) A wireless device that serves as the central connection point of a wireless LAN and mediates communication between wireless computers.
ad hoc mode
ad hoc mode Sometimes called “peer-to-peer mode,” it’s a wireless mode of operation typically used only in small or temporary installations. There’s no central device, and data travels from one device to another to reach the destination device.
Address Resolution Protocol (ARP)
An Internetwork-layer protocol used to resolve a host’s IP address to its MAC address. ARP uses a broadcast frame containing the target host’s IP address, and the host that’s assigned the address responds with its MAC address.
Authentication
The process of identifying who has access to the network. The most common form of authentication is a logon with a username and password.
Authorization
The process of granting or denying an authenticated user’s access to network resources.
Baseband
A type of signaling used in networks in which each bit of data is represented by a pulse of electricity (on copper media) or light (on fiber-optic media). These signals are sent at a single fixed frequency, using the medium’s entire bandwidth. LAN technologies use baseband signaling.
Basic input/output system (BIOS)
The firmware found on many PCs that is executed when the computer is powered on. Its primary task is to tell the CPU to perform certain tasks when power is
first applied to the computer, including initializing motherboard hardware, performing a power-on self-test (POST), and beginning the boot procedure.
Broadband
A type of signaling that uses analog techniques to encode binary 1s and 0s across a continuous range of values. Broadband signals move across the medium in the form of continuous electromagnetic or optical waves rather than discrete pulses. Signals flow at a particular frequency, and each frequency represents a channel of data, allowing multiple streams of data on a single wire. TV and cable Internet use broadband signaling.
Broadcast domain
The scope of devices to which broadcast frames are forwarded. Router interfaces delimit broadcast domains because they don’t forward broadcasts, whereas switches and hubs do.
Bus
A collection of wires that carry data from one place to another on a computer’s motherboard.
Byte
A collection of 8 bits that might represent a number or a printable character.
Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
A media access method in which a device must first listen (carrier sense) to the medium to be sure no other device is transmitting. If two devices transmit at the same time (multiple access), a collision occurs and is detected (collision detection). In this case, all devices involved in the collision wait for a random period of time before transmitting again.
Clear to send (CTS)
A signal an AP generates in response to a request-to-send signal. A CTS signal indicates that the computer that sent an RTS can transmit data. See also access point (AP) and request to send (RTS).
Client
The term used to describe an OS designed mainly to access network resources, a computer’s primary role in a network (running user applications and accessing network resources), and software that requests network resources from servers.
Client-to-site VPN
mode A VPN mode that establishes a VPN connection between a single client computer and a VPN device.
Cloud computing
A networking model in which data, applications, and processing power are managed by servers on the Internet, and users of these resources pay for what they use rather than the equipment and software needed to provide resources.
Cloud storage
A data storage method in which some or all of an organization’s data is stored on servers located offsite and maintained by a storage hosting company.
Collision
The result of two or more devices on the same medium transmitting simultaneously when CSMA/CD is the media access method in use. See also Carrier Sense Multiple Access with Collision Detection (CSMA/CD).
Collision domain
The extent to which signals in an Ethernet bus topology network are propagated. All devices connected to a logical bus topology network are in the same collision domain. Switch and router ports delimit collision domains.
Data Link layer
Layer 2 in the OSI model is responsible for managing access to the network medium and delivery of data frames from sender to receiver or from sender to an intermediate device, such as a router. See also Open Systems Interconnection (OSI) reference model.
Dedicated bandwidth
A property of switches in which each port’s bandwidth is dedicated to the devices connected to the port.
Datagram
The unit of information used by UDP in the Transport layer. A datagram is passed up to the Application layer as data and passed down to the Internetwork layer, where it becomes a packet.