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server looks up the requested domain name to find its
corresponding IP address. If the DNS server cannot find the IP
address, it communicates with higher-level DNS servers to
determine the IP address. See
domain name.
domain name
A domain name is a user-friendly name used in place of its
associated IP address. Domain names must be unique; their
assignment is controlled by the Internet Corporation for Assigned
Names and Numbers (ICANN). Domain names are a key
element of URLs, which identify a specific file at a web site. See
DNS.
download
To transfer data in the downstream direction, i.e., from the
Internet to the user.
DSL
Digital Subscriber Line
A technology that allows both digital data and analog voice
signals to travel over existing copper telephone lines.
encryption keys
See
network keys
Ethernet
The most commonly installed computer network technology,
usually using twisted pair wiring. Ethernet data rates are 10
Mbps and 100 Mbps.
See also 10BASE-T, 100BASE-T, twisted
pair
.
FTP
File Transfer Protocol
A program used to transfer files between computers connected
to the Internet. Common uses include uploading new or updated
files to a web server, and downloading files from a web server.
Gbps
Abbreviation of Gigabits per second, or one billion bits per
second. Internet data rates are often expressed in Gbps.
host
A system (usually a computer) connected to a network.
HTTP
Hyper-Text Transfer Protocol
HTTP is the main protocol used to transfer data from web sites
so that it can be displayed by web browsers. See
web browser,
web site
.
Hub
A hub is a place of convergence where data arrives from one or
more directions and is forwarded out in one or more directions. It
connects an Ethernet bridge/router to a group of PCs on a LAN
and allows communication to pass between the networked
devices.
ICMP
Internet Control Message Protocol
An Internet protocol used to report errors and other network-
related information. The ping command makes use of ICMP.
IEEE
The Institute of Electrical and Electronics Engineers is a
technical professional society that fosters the development of
standards that often become national and international
standards.
Internet
The global collection of interconnected networks used for both
private and business communications.
intranet
A private, company-internal network that looks like part of the
Internet (users access information using web browsers), but is
accessible only by employees.
IP
See TCP/IP
.
IP address
Internet Protocol address
The address of a host (computer) on the Internet, consisting of
four numbers, each from 0 to 255, separated by periods, e.g.,
209.191.4.240. An IP address consists of a
network ID
that
identifies the particular network the host belongs to, and a
host
ID
uniquely identifying the host itself on that network. A network
mask is used to define the network ID and the host ID. Because
IP addresses are difficult to remember, they usually have an
