Garmin HN294DP/DI manual Domain name, DOS attack, Downstream, Dslam

Important Information

DNS

Short for Domain Name System (or Service), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned.

Domain name

A name that identifies one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages. Because the Internet is based on IP addresses, not domain names, every Web server requires a Domain Name System (DNS) server to translate domain names into IP addresses.

DOS attack

DOS (Denial of service) attack is a method of flooding a site with "spoofed" (artificially generated) packets. A DOS tries to generate enough traffic deny service to legitimate users. One recent method has been called "smurfing".

Downstream

The direction of a downstream signal is from the ISP/service provider to the user's computer (downloading).

DSL

Short for Digital Subscriber Line, which is a data communications technology that transmits information over the existing copper telephone lines (POTS). DSL takes existing voice cables that connect customer premises (CPE) to the phone company's central office (CO) and turns them into a high-speed digital link. There are many types of DSL and ADSL is one of them.

DSLAM

Short for Digital Subscriber Line Access Multiplexer, a mechanism at a phone company's central location that links many customer DSL connections to a single high-speed ATM line. When the phone company receives a DSL signal, an ADSL modem with a POTS splitter detects voice calls and data. Voice calls are sent to the PSTN, and data are sent to the DSLAM, where it passes through the ATM to the Internet, then back through the DSLAM and ADSL modem before returning to the customer's PC.

90 EN/LZT 108 6377 R4 - September 2003