NETWORK+ Terms D's

Question 1

In a frame, the field or section that contains the data.

Answer 1

Data field

Question 2

Layer 2 of the OSI model, which is above the physical layer. Data comes off the cable, goes
through the physical layer, and goes into the data link layer. The ___ ___ layer has two distinct sublayers: MAC and LLC.

Answer 2

data link layer

Question 3

An information grouping transmitted as a unit at the network layer.

Answer 3

datagram

Question 4

A 25-pin connector used for serial port or parallel port connection between PCs and peripheral devices.

Answer 4

DB-25

Question 5

A nine-pin connector used
for serial port or parallel port connection
between PCs and peripheral
devices.

Answer 5

DB-9

Question 6

The channel used on ISDN to communicate signaling and other related information.
Use of the ____ ____ leaves the B channels free for data communication. See also B (bearer) channel.

Answer 6

D (delta) channel

Question 7

A form of DNS that enables systems to be registered and deregistered with DNS dynamically___ ___ ___ ___ is facilitated by DHCP, which passes IP address assignments
to the DNS server for entry into the DNS server records. This is in contrast with the conventional DNS system, in which entries must be manually made.

Answer 7

DDNS (Dynamic Domain Name

Service)

Question 8

A DoS attack that utilizes more than

one computer in the attack.

Answer 8

DDoS (Distributed Denial of Service)

Question 9

A format for storing computer data on a
DAT. ___ ___ ___ -formatted tapes can be
read by either a this or a DAT drive.
The original one of these is standard specified a 4mm tape cartridge with a capacity of 1.3GB. Subsequent implementations of DDS have taken the capacity to 40GB with compression.

Answer 9

DDS (digital data storage)

Question 10

A dedicated circuit used in WANs to provide a constant connection between two points.

Answer 10

dedicated line

Question 11

Normally a router or a multihomed computer to which packets are sent when they
are destined for a host on a different
network.

Answer 11

default gateway

Question 12

The point at which communication lines enter a customer’s premises. Sometimes shortened to simply demarc.

Answer 12

demarcation point

Question 13

The network address to which data is sent

Answer 13

destination address

Question 14

A protocol that provides dynamic IP addressing to ___ ___ ___ protocol enabled workstations on the network.

Answer 14

DHCP (Dynamic Host Configuration

Protocol)

Question 15

Refers to the connection of a remote node to a network using POTS.

Answer 15

dialup networking

Question 16

A backup of only the data that has been created or changed since the previous full
backup. In a ____ ____, the state of the archive bits is not altered.

Answer 16

differential backup

Question 17

On a Linux, UNIX, or Macintosh system, you can use the ____ command to perform manual DNS lookups.

Answer 17

dig

Question 18

A system that enables network resources to be viewed as objects stored in a database.
This database can then be divided and distributed among different servers on the network. Examples of ___ ___ systems include Novell Directory Services and Microsoft Active Directory.

Answer 18

directory services

Question 19

A plan for implementing duplicate computer
services if a natural disaster, a human-made disaster, or another catastrophe occurs. A ___ ___ ___ includes offsite backups and procedures to activate information systems in alternative locations.

Answer 19

disaster recovery plan

Question 20

A fault-tolerant standard based on RAID 1 that uses disk mirroring with dual disk controllers.

Answer 20

disk duplexing

Question 21

A fault-tolerant standard that is defined as RAID 1 and mirrors data between two disks
to create an exact copy.

Answer 21

disk mirroring

Question 22

An implementation of RAID in which data is distributed across multiple disks in a stripe.
Some striping implementations provide
performance improvements (RAID 0), whereas others provide fault tolerance (RAID 5).

Answer 22

disk striping

Question 23

A type of routing in which a router uses

broadcasts to inform neighboring routers on the network of the routes it knows about. Compare with linkstate routing.

Answer 23

distance-vector routing

Question 24

The service provided by the data link layer of

the OSI model.

Answer 24

DLC (Data Link Control)

Question 25

An area for placing web and other servers
that serve the general public outside
the firewall, therefore isolating them
from internal network access.

Answer 25

DMZ (Demilitarized Zone)

Question 26

A system used to translate domain
names, such as www.quepublishing.com, into IP addresses, such as 165.193.123.44.
___ ___ ___ uses a hierarchical namespace that enables the database of hostname-to-IP address mappings to be distributed across multiple servers.

Answer 26

DNS (Domain Name Service)

Question 27

A telecommunications standard for
transmitting high-speed data over
existing cable TV systems.

Answer 27

DOCSIS (Data-Over-Cable Service

Interface Specification)

Question 28

A logical boundary of an Active Directory Structure on Windows servers. Also, a section of the DNS namespace.

Answer 28

domain

Question 29

A server that runs application software that
enables the server to perform a role
associated with this service.

Answer 29

domain name server

Question 30

A type of hacking attack in which the
target system is overwhelmed with
requests for service, which keeps it
from servicing any requests—legitimate
or otherwise.

Answer 30

DoS (denial of service) attack

Question 31

A period of time during which a computer system or network is unavailable. This may be
due to scheduled maintenance or
hardware or software failure.

Answer 31

downtime

Question 32

A public network technology that
delivers high bandwidth over conventional
copper wiring over limited
distances.

Answer 32

DSL (Digital Subscriber Line)

Question 33

A network communications device that formats and controls data for transmission
over digital lines. A DSU is used
with a CSU.

Answer 33

DSU (data service unit)

Question 34

A device used at the user end of a user
network interface that serves as a
data source, a destination, or both.
\_\_\_  \_\_\_  \_\_\_  devices include computers,
protocol translators, and
multiplexers.

Answer 34

DTE (data terminal equipment)

Question 35

A keyboard/monitor combination that enables access to a multiuser system but provides
no processing or storage at the local
level.

Answer 35

dumb terminal

Question 36

In RAID, a RAID 1 mirror set in which each drive is connected to a separate controller to
eliminate the single point of failure
that the controller created.

Answer 36

duplexing

Question 37

A form of multiplexing optical signals that replaces SONET/SDH regenerators with
erbium doped fiber amplifiers (EDFAs) and can also amplify the signal and allow it to travel a greater distance. The main components of a ___ ___ ___ ___ system include a terminal multiplexer, line repeaters, and a
terminal demultiplexer.

Answer 37

DWDM (Dense Wavelength Division

Multiplexing)

Question 38

A routing system that enables routing information to be communicated between devices 618 DLC (Data Link Control)
automatically and that can recognize
changes in the network topology
and update routing tables accordingly.
Compare with static routing.

Answer 38

dynamic routing

Question 39

A flow control mechanism that prevents the sender of data from overwhelming the
receiver. The amount of data that
can be buffered in a ___ ___
varies in size, hence its name.

Answer 39

dynamic window