B

B

Glossary

This glossary defines some of the terms and acronyms used in this document.

TERM

DEFINITION

 

 

Authentication

A process where the CMTS verifies that access is authorized, using a

 

password, trusted IP address, or serial number.

 

 

cable modem

A device installed at a subscriber location to provide data

 

communications over an HFC network. Unless otherwise specified,

 

all references to “cable modem” in this documentation refer to

 

DOCSIS cable modems only.

 

 

coaxial cable

A type of cable consisting of a center wire surrounded by insulation

 

and a grounded shield of braided (coax) wire. The shield minimizes

 

electrical and radio frequency interference. Coaxial cable has high

 

bandwidth and can support transmission over long distances.

 

 

DHCP

Dynamic Host Configuration Protocol server — dynamically assigns

 

IP addresses to client hosts on an IP network. DHCP eliminates

 

manually assigning 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.

 

 

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.

 

 

downstream

In a cable data network, this is the direction of the data received by

 

the computer from the Internet.

 

 

firewall

A security software system on the SBG901 that enforces an access

 

control policy between the Internet and the SBG901 LAN.

 

 

B • Glossary

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