Motorola SURFboard SBG901, Руководство пользователя

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B Glossary 109
This document is uncontrolled pending incorporation in PDM
TERM DEFINITION
demodulation An operation to restore a previously modulated wave and separate the
multiple signals that were combined and modulated on a sub carrier.
DHCP
A Dynamic Host Configuration Protocol server dynamically assigns IP
addresses to client hosts on an IP network. DHCP eliminates the need
to manually assign static IP addresses by “leasing” an IP address and
subnet mask to each client. It enables the automatic reuse of unused
IP addresses.
The SBG901 is simultaneously a DHCP client and a DHCP server.
A DHCP server at the cable system headend assigns a public IP
address to the SBG901 and optionally to clients on the SBG901 LAN.
The SBG901 contains a built-in DHCP server that assigns private IP
addresses to clients.
Distortion
An undesired change in signal waveform within a transmission
medium. A nonlinear reproduction of the input waveform.
DMZ
A “de-militarized zone” is one or more hosts logically located between
a private LAN and the Internet. A DMZ prevents direct access by
outside users to private data. (The term comes from the geographic
buffers located between some conflicting countries, such as North and
South Korea.) In a typical small DMZ configuration, the DMZ host
receives requests from private LAN users to access external web sites
and initiates sessions for these requests. The DMZ host cannot initiate
a session back to the private LAN. Internet users outside the private
LAN can access only the DMZ host. You can use a DMZ to set up a
web server or for gaming without exposing confidential data.
DNS The Domain Name System is the Internet system for converting
domain names to IP addresses. A DNS server contains a table
matching domain names, such as Internetname.com, to IP addresses,
such as 192.169.9.1. When you access the world-wide web, a DNS
server translates the URL displayed on the browser to the destination
website IP address. The DNS lookup table is a distributed Internet
database; no one DNS server lists all domain names to IP address
matches.
DOCSIS The CableLabs Data-Over-Cable Service Interface Specification defines
interface standards for cable modems, gateways, and supporting
equipment to deliver data between an HFC network and computer
systems or television sets. To emphasize its use as a cable modem
standard, DOCSIS is now called CableLabs Certified Cable Modems.
Euro-DOCSIS is DOCSIS adapted for use in Europe.