Dual-Band Wireless A+B Broadband Router
CSMA/CD
(
C
arrier
S
ense
M
ultiple
A
ccess/
C
ollision
D
etection) - The LAN
access method used in Ethernet. When a device wants to gain access to the net-
work, it checks to see if the network is quiet (senses the carrier). If it is not, it
waits a random amount of time before retrying. If the network is quiet and two
devices access the line at exactly the same time, their signals collide. When the
collision is detected, they both back off and each waits a random amount of
time before retrying.
CTS
(
C
lear
T
o
S
end) - An RS-232 signal sent from the receiving station to the
transmitting station that indicates it is ready to accept data.
Database
- A database is a collection of data that is organized so that its con-
tents can easily be accessed, managed, and updated.
Data Packet
- One frame in a packet-switched message. Most data communi-
cations is based on dividing the transmitted message into packets. For example,
an Ethernet packet can be from 64 to 1518 bytes in length.
Default Gateway
- The routing device used to forward all traffic that is not
addressed to a station within the local subnet.
DHCP
(
D
ynamic
H
ost
C
onfiguration
P
rotocol) - A protocol that lets network
administrators centrally manage and automate the assignment of Internet
Protocol (IP) addresses in an organization's network. Using the Internet’s set of
protocol (TCP/IP), each machine that can connect to the Internet needs a
unique IP address. When an organization sets up its computer users with a con-
nection to the Internet, an IP address must be assigned to each machine.
Without DHCP, the IP address must be entered manually at each computer and,
if computers move to another location in another part of the network, a new IP
address must be entered. DHCP lets a network administrator supervise and dis-
tribute IP addresses from a central point and automatically sends a new IP
address when a computer is plugged into a different place in the network.
DHCP uses the concept of a “lease” or amount of time that a given IP address
will be valid for a computer. The lease time can vary depending on how long a
user is likely to require the Internet connection at a particular location. It’s espe-
cially useful in education and other environments where users change fre-
quently. Using very short leases, DHCP can dynamically reconfigure networks
in which there are more computers than there are available IP addresses.
DHCP supports static addresses for computers containing Web servers that
need a permanent IP address.
111
Instant Wireless
®
Series
110
on startup. These instructions search for the operating system, load it, and pass
control to it.
Bottleneck
– A traffic slowdown that results when too many network nodes try
to access a single node, often a server node, at once.
Bridge
- A device that interconnects different networks together.
Broadband
- A data-transmission scheme in which multiple signals share the
bandwidth of a medium. This allows the transmission of voice, data, and video
signals over a single medium. Cable television uses broadband techniques to
deliver dozens of channels over one cable.
Browser
- A browser is an application program that provides a way to look at
and interact with all the information on the World Wide Web or PC. The word
“browser” seems to have originated prior to the Web as a generic term for user
interfaces that let you browse text files online.
Buffer
- A buffer is a shared or assigned memory area used by hardware
devices or program processes that operate at different speeds or with different
sets of priorities. The buffer allows each device or process to operate without
being held up by the other. In order for a buffer to be effective, the size of the
buffer and the algorithms for moving data into and out of the buffer need to be
considered by the buffer designer. Like a cache, a buffer is a “midpoint hold-
ing place” but exists not so much to accelerate the speed of an activity as to
support the coordination of separate activities.
Cable Modem
- A device that connects a computer to the cable television net-
work, which in turn connects to the Internet. Once connected, cable modem
users have a continuous connection to the Internet. Cable modems feature
asymmetric transfer rates: around 36 Mbps downstream (from the Internet to
the computer), and from 200 Kbps to 2 Mbps upstream (from the computer to
the Internet).
CAT 5
- ANSI/EIA (American National Standards Institute/Electronic
Industries Association) Standard 568 is one of several standards that specify
“categories” (the singular is commonly referred to as “CAT”) of twisted pair
cabling systems (wires, junctions, and connectors) in terms of the data rates
that they can sustain. CAT 5 cable has a maximum throughput of 100 Mbps and
is usually utilized for 100BaseTX networks.
CPU
(
C
entral
P
rocessing
U
nit) - The computing part of the computer. Also
called the “processor,” it is made up of the control unit and ALU.
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