ZyXEL Communications Prestige 964 User Manual page 45

log on. DHCP centralizes IP address management on central computers that run the DHCP server
program. DHCP leases addresses for a period of time which means that addresses are made
available to assign to other systems.
Digital Signature Digital code that authenticates whomever signed the document or software. Software, messages,
Email, and other electronic documents can be signed electronically so that they cannot be altered
by anyone else. If someone alters a signed document, the signature is no longer valid. Digital
signatures are created when someone generates a hash from a message, then encrypts and sends
both the hash and the message to the intended recipient. The recipient decrypts the hash and
original message, makes a new hash on the message itself, and compares the new hash with the
old one. If the hashes are the same, the recipient knows that the message has not been changed.
Also see Public-key encryption.
DNS Domain Name System. A database of domain names and their IP addresses. DNS is the primary
naming system for many distributed networks, including the Internet.
Data over Cable Service Interface Specification. It is the dominating cable modem standard,
DOCSIS
which defines technical specifications for both cable modem and CMTS.
Domain Name The unique name that identifies an Internet site. Domain Names always have 2 or more parts,
separated by dots. The part on the left is the most specific, and the part on the right is the most
general.
The data flowing from the CMTS to the cable modem.
Downstream
The frequency used for transmitting data from the CMTS to the cable modem. Normally in the
Downstream
42/65-850 MHz range depending on the actual cable plant capabilities.
Frequency
DRAM Dynamic RAM that stores information in capacitors that must be refreshed periodically.
DTE Originally, the DTE (data terminal equipment) meant 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.
Encryption The act of substituting numbers and characters in a file so that the file is unreadable until it is
decrypted. Encryption is usually done using a mathematical formula that determines how the file
is decrypted.
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.
Events These are network activities. Some activities are direct attacks on your system, while others
might be depending on the circumstances. Therefore, any activity, regardless of severity is called
an event. An event may or may not be a direct attack on your system.
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.
Firewall A hardware or software "wall" that restricts access in and out of a network. Firewalls are most
often used to separate an internal LAN or WAN from the Internet.
Glossary
Prestige 964 Cable Router
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