Wireless Network Access Point
43
Instant Wireless
®
Series
42
Infrastructure Network - An infrastructure network is a group of computers
or other devices, each with a wireless adapter, connected as an 802.11 wireless
LAN. In infrastructure mode, the wireless devices communicate with each
other and to a wired network by first going through an access point. An infra-
structure wireless network connected to a wired network is referred to as a
Basic Service Set (BSS). A set of two or more BSS in a single network is
referred to as an Extended Service Set (ESS). Infrastructure mode is useful at
a corporation scale, or when it is necessary to connect the wired and wireless
networks.
IP Address - In the most widely installed level of the Internet Protocol
(Internet Protocol) today, an IP address is a 32-binary digit number that identi-
fies each sender or receiver of information that is sent in packet across the
Internet. When you request an HTML page or send e-mail, the Internet
Protocol part of TCP/IP includes your IP address in the message (actually, in
each of the packets if more than one is required) and sends it to the IP address
that is obtained by looking up the domain name in the Uniform Resource
Locator you requested or in the e-mail address you're sending a note to. At the
other end, the recipient can see the IP address of the Web page requestor or the
e-mail sender and can respond by sending another message using the IP address
it received.
ISM band - The FCC and their counterparts outside of the U.S. have set aside
bandwidth for unlicensed use in the ISM (Industrial, Scientific and Medical)
band. Spectrum in the vicinity of 2.4 GHz, in particular, is being made avail-
able worldwide. This presents a truly revolutionary opportunity to place con-
venient high-speed wireless capabilities in the hands of users around the globe.
LAN - A local area network (LAN) is a group of computers and associated
devices that share a common communications line and typically share the
resources of a single processor or server within a small geographic area (for
example, within an office building).
MAC (Media Access Control) Address - A unique number assigned by the
manufacturer to any Ethernet networking device, such as a network adapter,
that allows the network to identify it at the hardware level.
Mbps (MegaBits Per Second) - One million bits per second; unit of measure-
ment for data transmission.
Multicasting - Sending data to a group of nodes instead of a single destination.
10 Mbps. Forms the underlying transport vehicle used by several upper-level
protocols, including TCP/IP and XNS.
FHSS (Frequency Hopping Spread Spectrum) - FHSS continuously changes
the center frequency of a conventional carrier several times per second accord-
ing to a pseudo-random set of channels, while chirp spread spectrum changes
the carrier frequency. Because a fixed frequency is not used, illegal monitoring
of spread spectrum signals is extremely difficult, if not downright impossible
depending on the particular method.
Firmware - Code that is written onto read-only memory (ROM) or program-
mable read-only memory (PROM). Once firmware has been written onto the
ROM or PROM, it is retained even when the device is turned off.
Fragmentation - Breaking a packet into smaller units when transmitting over
a network medium that cannot support the original size of the packet.
Gateway - A device that interconnects networks with different, incompatible
communications protocols.
Hardware - Hardware is the physical aspect of computers, telecommunica-
tions, and other information technology devices. The term arose as a way to dis-
tinguish the “box” and the electronic circuitry and components of a computer
from the program you put in it to make it do things. The program came to be
known as the software.
Hub - The device that serves as the central location for attaching wires from
workstations. Can be passive, where there is no amplification of the signals; or
active, where the hubs are used like repeaters to provide an extension of the
cable that connects to a workstation.
IEEE (The Institute of Electrical and Electronics Engineers) - The IEEE
describes itself as “the world's largest technical professional society, promoting
the development and application of electrotechnology and allied sciences for
the benefit of humanity, the advancement of the profession, and the well-being
of our members.”
The IEEE fosters the development of standards that often become national and
international standards. The organization publishes a number of journals, has
many local chapters, and several large societies in special areas, such as the
IEEE Computer Society.
