ZyXEL Communications Prestige 642 User Manual page 59

Prestige 642 ADSL Internet Access Router
subsequent communications.
Domain
The unique name that identifies an Internet site. Domain Names always have 2 or more parts,
Name
separated by dots. The part on the left is the most specific, and the part on the right is the
most general.
DRAM Dynamic RAM that stores information in capacitors that must be refreshed periodically.
DSL Digital Subscriber Line technologies enhances the data capacity of the existing twisted-pair
wire that runs between the local telephone company switching offices and most homes and
offices. There are actually seven types of DSL service, ranging in speeds from 16 Kbits/sec to
52 Mbits/sec. The services are either symmetrical (traffic flows at the same speed in both
directions), or asymmetrical (the downstream capacity is higher than the upstream capacity).
DSL connections are point-to-point dedicated circuits, meaning that they are always
connected. There is no dial-up. There is also no switching, which means that the line is a
direct connection into the carrier's frame relay, ATM (Asynchronous Transfer Mode), or
Internet-connect system.
DSLAM
A Digital Subscriber Line Access Multiplexer (DSLAM) is a network device, usually at a
telephone company central office, that receives signals from multiple customer Digital
Subscriber Line connections and puts the signals on a high-speed backbone line using
multiplexing techniques. Depending on the product, DSLAM multiplexers connect DSL lines
with some combination of asynchronous transfer mode ATM, frame relay, or IP networks.
DTE Originally, the DTE (data terminal equipment) was a dumb terminal or printer, but today it is a
computer, or a bridge or router that interconnects local area networks.
EMI
ElectroMagnetic Interference. The interference by electromagnetic signals that can cause
reduced data integrity and increased error rates on transmission channels.
Ethernet
A very common method of networking computers in a LAN. There are a number of
adaptations to the IEEE 802.3 Ethernet standard, including adaptations with data rates of 10
Mbits/sec and 100 Mbits/sec over coaxial cable, twisted-pair cable, and fiber-optic cable. The
latest version of Ethernet, Gigabit Ethernet, has a data rate of 1 Gbit/sec.
FAQ
(Frequently Asked Questions) -- FAQs are documents that list and answer the most common
questions on a particular subject.
FCC
The FCC (Federal Communications Commission) is in charge of allocating the
electromagnetic spectrum and thus the bandwidth of various communication systems.
Flash The nonvolatile storage that can be electrically erased and reprogrammed so that data can be
memory stored, booted, and rewritten as necessary.
Gateway
A gateway is a computer system or other device that acts as a translator between two
systems that do not use the same communication protocols, data formatting structures,
languages, and/or architecture.
Host
Any computer on a network that is a repository for services available to other computers on
the network. It is quite common to have one host machine provide several services, such as
WWW and USENET.
IANA Internet Assigned Number Authority acts as the clearinghouse to assign and coordinate the
use of numerous Internet protocol parameters such as Internet addresses, domain names,
protocol numbers, and more. The IANA Web site is at http://www.isi.edu/iana.
ICMP
Internet Control Message Protocol is a message control and error-reporting protocol between
a host server and a gateway to the Internet. ICMP uses Internet Protocol (IP) datagrams, but
the messages are processed by the TCP/IP software and are not directly apparent to the
application user.
internet (Lower case i) Any time you connect 2 or more networks together, you have an internet.
B Glossary