beautypg.com

Asus SL1000 User Manual

Page 160

background image

Appendix 16. Glossary

Internet Security Router User

’s Manual

144

element of URLs, which identify a specific file at a web site, e.g.,

http://www.asus.com

.

See also 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.

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
.

filtering

To screen out selected types of data, based on filtering rules. Filtering can be applied in

one direction (upstream or downstream), or in both directions.

filtering rule

A rule that specifies what kinds of data the a routing device will accept and/or reject.

Filtering rules are defined to operate on an interface (or multiple interfaces) and in a
particular direction (upstream, downstream, or both).

firewall

Any method of protecting a computer or LAN connected to the Internet from intrusion or

attack from the outside. Some firewall protection can be provided by packet filtering
and Network Address Translation services.

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.

hop

When you send data through the Internet, it is sent first from your computer to a router,

and then from one router to another until it finally reaches a router that is directly
connected to the recipient. Each individual

“leg” of the data’s journey is called a hop.

hop count

The number of hops that data has taken on its route to its destination. Alternatively, the

maximum number of hops that a packet is allowed to take before being discarded (see
also TTL
).

host

A device (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 also web browser, web site.

ICMP

Internet Control Message Protocol

An Internet protocol used to report errors and other network-related information. The
ping command makes use of ICMP.

IGMP

Internet Group Management Protocol

An Internet protocol that enables a computer to share information about its membership in
multicast groups with adjacent routers. A multicast group of computers is one whose
members have designated as interested in receiving specific content from the others.
Multicasting to an IGMP group can be used to simultaneously update the address books
of a group of mobile computer users or to send company newsletters to a distribution list.

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