An IEEE standard (802.3) for operating 10 Mbps Ethernet networks
(LANs) with twisted pair cabling and a wiring hub.
Mode A client setting that provides independent peer-to-peer
connectivity in a wireless LAN. ZoomAir Wireless LAN cards
provide an "instant" Ad-Hoc network with all the required
drivers and setup utilities. An alternative set-up is where
PCs communicate with each other through an AP. See AP and
AP (Access Point). A hardware
device, or software used in conjunction with a computer, that
serves as a communications "hub" for wireless clients and
provides a connection to a wired LAN. An AP can double the
range of wireless clients and provide enhanced security. ZoomAir's
software-based AP is an inexpensive alternative to dedicated
Application software A software program
running on top of the operating system (Windows, UNIX, Mac)
that has been created to perform a specific task for a user.
Examples include word processing software like Word/Word Perfect,
spreadsheets like Excel or Lotus 123, home finance packages
like Quicken, etc.
Client Any computer connected
to a network that requests services (files, print capability)
from another member of the network.
Sense Multiple Access/Collision Avoidance): CSMA/CA is the
principle medium access method employed by IEEE 802.11 WLANs.
It is a "listen before talk" method of minimizing (but not
eliminating) collisions caused by simultaneous transmission
by multiple radios. IEEE 802.11 states collision avoidance
method rather than collision detection must be used, because
the standard employs half duplex radios - radios capable of
transmission or reception, but not both simultaneously.
conventional wired Ethernet nodes, a WLAN station cannot detect
a collision while transmitting. If a collision occurs, the
transmitting station will not receive an ACKnowledge packet
from the intended receive station. For this reason, ACK packets
have a higher priority than all other network traffic. After
completion of a data transmission, the receive station will
begin transmission of the ACK packet before any other node
can begin transmitting a new data packet. All other stations
must wait a longer pseudo randomized period of time before
transmitting. If an ACK packet is not received, the transmitting
station will wait for a subsequent opportunity to retry transmission.
CSMA/CD (Carrier Sense Multiple Access/Collision Detection).
The LAN access method used in Ethernet. When a device wants
to gain access to the network, it checks to see if the network
is free. If it is not, it waits a random amount of time before
retrying. If the network is free 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 wait
a random amount of time before retrying.
Data Over Cable Service Interface Specification. The governing
body, which certifies cable modem vendors, is called CableLabs®.
The DOCSIS standard and close derivatives are also being adopted
in other countries around the world. Currently, CableLabs
is certifying DOCSIS revision 1.0 cable modems.
and FHSS Wireless LAN products are available in three
different technologies -- direct-sequencing spread-spectrum
(DSSS), frequency-hopping spread-spectrum (FHSS) and infrared.
DSSS and FHSS are spread-spectrum techniques that operate
over the radio airwaves in the unlicensed ISM band (industrial,
scientific, and medical). DSSS uses a radio transmitter to
spread data packets over a fixed range of the frequency band.
FHSS uses a technique by which the signal transmitted hops
among several frequencies at a specific rate and sequence
as a way of avoiding interference. ZoomAir incorporates DSSS.
Ethernet The most widely used LAN access method, which
is defined by the IEEE 802.3 standard. Ethernet is normally
a shared media LAN meaning all devices on the network segment
share total bandwidth. Ethernet networks operate at 10Mbps
using CSMA/CD to run over 10-BaseT cables.
Division Multiplexing). A technology that transmits multiple
signals simultaneously over a single transmission path, such
as a cable or wireless system. Each signal travels within
its own unique frequency range. HomeLAN uses this to ensure
compatibility between the different services sharing the same
telephone wire, specifically voice, xDSL and the home network.
Each service has a frequency spectrum that is different from
the others to eliminate interference.
network point that acts as an entrance to another network.
HomePNA (Home Phoneline Networking Alliance). An association
of industry-leading companies working together to help ensure
adoption of a single, unified phoneline networking industry
standard and rapidly bring to market a range of interoperable
home networking solutions. HomeLAN complies with the HomePNA
standards and is a member of the organization.
(Hertz). The international unit for measuring frequency, equivalent
to the older unit of cycles per second. One megahertz (MHz)
is one million hertz. One gigahertz (GHz) is one billion hertz.
The standard US electrical power frequency is 60 Hz, the AM
broadcast radio frequency band is 0.551.6 MHz, the FM broadcast
radio frequency band is 88108 MHz, and wireless 802.11 LANs
operate at 2.4 GHz.
IEEE (Institute of Electrical
and Electronics Engineers, New York, www.ieee.org). A membership
organization that includes engineers, scientists and students
in electronics and allied fields. It has more than 300,000
members and is involved with setting standards for computers
and communications. HomePNA uses the IEEE standard (802.3
CSMA/CD) to enable the sharing of the telephone wiring with
other devices on the home network. ZoomAir wireless network
cards support IEEE 802.11.
IEEE 802.11 IEEE 802.xx
is a set of specifications for LANs from The Institute of
Electrical and Electronic Engineers (IEEE). Most wired networks
conform to 802.3, the specification for CSMA/CD based Ethernet
networks or 802.5, the specification for token ring networks.
802.11 defines the standard for wireless LANs encompassing
three incompatible (non-interoperable) technologies: Frequency
Hopping Spread Spectrum (FHSS), Direct Sequence Spread Spectrum
(DSSS), and Infrared.
IEEE 802.11b High Rate A revision
of 802.11 standard that provides much higher data rates up
to 11Mbps, while maintaining the 802.11 protocol.
Mode A client setting providing connectivity to an AP.
As compared to Ad-Hoc Mode where PCs communicate directly
with each other, clients set in Infrastructure Mode all pass
data through a central AP. The AP not only mediates wireless
network traffic in the immediate neighborhood, but also provides
communication with the wired network. See AD-Hoc and AP.
The Internet Protocol (IP) is a method or protocol by which
data is sent from one computer to another on a network, i.e.
the Internet. Each computer on the Internet has at least one
address that uniquely identifies it from all other computers
on the Internet. When you send or receive data (for example,
an e-mail note or a Web page), the message gets divided into
little chunks called packets. Each of these packets contains
both the sender's Internet address and the receiver's address.
Any packet is sent first to a gateway computer that understands
a small part of the Internet. The gateway computer reads the
destination address and forwards the packet to an adjacent
gateway that in turn reads the destination address and so
forth across the Internet until one gateway recognizes the
packet as belonging to a computer within its immediate neighborhood
or domain. That gateway then forwards the packet directly
to the computer whose address is specified. Because the data
is divided into a number of packets, each packet can, if necessary,
be sent by a different route across the Internet. A packet
is treated as an independent unit of data so packets can arrive
at their destination in a different order than they were sent
in. Another protocol, the Transmission Control Protocol, (TCP)
then reassembles the packets in the right order.
Address An IP address is a 32-bit number that identifies
each sender or receiver of information that is sent across
the Internet. An IP address has two parts: the identifier
of a particular network on the Internet and an identifier
of the particular device (which can be a server or a workstation)
within that network.
ISO Network Model: The International
Standards Organization (ISO) has developed a network model
that consists of seven different levels, or layers. By standardizing
these layers, and the interfaces in between, different portions
of a given protocol can be modified or changed as technologies
advance, or systems requirements are altered. The seven layers
- Data Link
The IEEE 802.11 Standard encompasses the physical layer (PHY)
and the lower portion of the data link layer. The lower portion
of the data link layer is often referred to as the Medium
Access Controller (MAC) sublayer.
Service Provider). An organization that provides access to
the Internet. Small ISPs provide service via modem and ISDN
while the larger ones also offer private line hookups (T1,
fractional T1, etc.). The major online services such as America
Online and CompuServe provide Internet access but are still
known as "online services", not ISPs. They offer the members
only content, forums and services in addition to Internet
LAN (Local Area Network). A communications
network that serves users within a defined geographical area.
The benefits include the sharing of Internet access, files
and equipment like printers and storage devices. Special network
cabling (10 BaseT) is often used to connect the PCs together.
Zoom/HomeLAN uses existing telephone wiring and ZoomAir uses
wireless communications, in a home or office, to network all
PCs together so there is no need to run an extra set of cables.
MAC (Medium Access Control): In a WLAN network card,
the MAC is radio controller protocol. It corresponds to the
ISO Network Model's level 2 Data Link layer. The IEEE 802.11
standard specifies the MAC protocol for medium sharing, packets
formats and addressing, and error detection.
(Network Address Translation) The translation of an Internet
Protocol address (IP address) used within one network to a
different IP address known within another network. One network
is designated the internal network and the other is the external.
The internal network then appears as one entity to the outside
world. In the case of HomeLAN, the NAT capability of the Internet
sharing software allows the sharing of one Internet connection
among all the PCs connected to the home network.
(Physical Layer): The PHY is the lowest layer within the OSI
Network Model. It deals primarily with transmission of the
raw bit stream over the PHYsical transport medium. In the
case of wireless LANs, the transport medium is free space.
The PHY defines parameters such as data rates, modulation
method, signaling parameters, transmitter/receiver synchronization,
etc. Within an actual radio implementation, the PHY corresponds
to the radio front end and baseband signal processing sections.
PCI A local bus standard for connecting peripherals
to a personal computer. Within a computer, the bus is the
transmission path on which signals and data transfers occur
between the CPU, system memory, and attached devices such
as a HomeLAN card, sound card, or CD-ROM drive.
Moving seamlessly from one AP coverage area to another with
no loss in connectivity is a standard feature with ZoomAir
SSID (Service Set ID). SSID is a group
name shared by every member of a ZoomAir wireless network.
Only client PCs with the same SSID are allowed to establish
TCP (Transmission Control Protocol)
A protocol used along with the Internet Protocol (IP) to send
data in the form of individual units (called packets) between
computers over the Internet. While IP takes care of handling
the actual delivery of the data, TCP takes care of keeping
track of the packets that a message is divided into for efficient
routing through the Internet. For example, when a web page
is downloaded from a web server, the TCP program layer in
that server divides the file into packets, numbers the packets,
and then forwards them individually to the IP program layer.
Although each packet has the same destination IP address,
it may get routed differently through the network. At the
other end, TCP reassembles the individual packets and waits
until they have all arrived to forward them as a single file.
WECA (Wireless Ethernet Compatibility Alliance) WECA's
mission is to certify interoperability of IEEE 802.11b High
Rate wireless networking products and to promote that standard
for the enterprise, small business, and the home. WECA will
grant a seal of interoperability to vendors upon successful
completion of prescribed test suites.
Equivalent Privacy). WEP data encryption is defined by the
802.11 standard to prevent (i) access to the network by "intruders"
using similar wireless LAN equipment and (ii) capture of wireless
LAN traffic through eavesdropping. In addition to the security
provided by SSID, ZoomAir incorporates WEP, allowing the administrator
to define a set of respective "Keys" for each wireless network
user based on a "Key String" passed through the WEP encryption
algorithm. Access is denied by anyone who does not have an
WAN (Wide Area Network). A wide area
network connects local area networks together. Typical WAN
interfaces include plain old telephone (POT) lines, digital
subscriber lines (DSL), ISDN, T1/T3, and cable.
(The Standard for Wireless Fidelity). The Wi-Fi brand
name represented in a consumer friendly logo will serve as
the awarded "seal of approval" for those WECA member products
that have successfully completed the prescribed interoperability
testing. Customers from enterprises to consumers can be assured
that products bearing this logo will work together.