User Manual

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devices access the line at exactly the same time, their signals collide. When the
collision is detected, they both back off and each wait a random amount of time
before retrying.
Database - A database is a collection of data that is organized so that its contents
can easily be accessed, managed, and updated.
Default Gateway - The routing device used to forward all traffic that is not
addressed to a station within the local subnet.
DHCP (Dynamic Host Configuration Protocol) - A protocol that lets network
administrators manage centrally 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 connection 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 distribute 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 frequently.
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.
Domain - A subnetwork comprised of a group of clients and servers under the
control of one security database. Dividing LANs into domains improves per-
formance and security.
Driver - A workstation or server software module that provides an interface
between a network interface card and the upper-layer protocol software running
in the computer; it is designed for a specific NIC, and is installed during the ini-
tial installation of a network-compatible client or server operating system.
Network PC Card
Chapter 11: Glossary
Ad-hoc Network - An ad-hoc network is a wireless network or other small net-
work in which some of the network devices are part of the network only for the
duration of a communications session while in some close proximity to the rest
of the network.
Architecture - The total design and implementation of the network. It includes
the network's topology, transmission technologies and communications proto-
cols, management and security systems, and any other attributes that give a net-
work a particular set of capabilities and functionalities.
Backbone - The part of a network that connects most of the systems and net-
works together and handles the most data.
Bandwidth - The transmission capacity of a given facility, in terms of how much
data the facility can transmit in a fixed amount of time; expressed in bits per sec-
ond (bps).
Bit - A binary digit. The value - 0 or 1-used in the binary numbering system.
Also, the smallest form of data.
BSS (Basic Service Set) - A group of Instant Wireless Network PC Card users
and an Access Point.
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 pri-
orities. 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 holding place" but exists
not so much to accelerate the speed of an activity as to support the coordination
of separate activities.
CSMA/CD (Carrier Sense Multiple Access/Collision Detection) - 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
Instant Wireless
TM
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