Wireless wp

Wireless LAN Networking
White Paper
Introduction • Roaming capability is desired; e.g., maintaining
connectivity from almost anywhere inside a
Wireless technology has helped to simplify home or business
networking by enabling multiple computer
• Network access is desired outdoors; e.g.,
users to simultaneously share resources
outside a home or office building
in a home or business without additional or
intrusive wiring. These resources might include
a broadband Internet connection, network Wireless LANs in the Office
printers, data files, and even streaming audio
and video. This kind of resource sharing has An 802.11 network is the ideal solution for a
become more prevalent as computer users network administrator in many respects. No
have changed their habits from using single, longer is it a requirement that every workstation
stand-alone computers to working on networks and conference room be wired up to hubs and
with multiple computers, each with potentially switches with cables in hard-to-reach areas.
different operating systems and varying Wireless networking allows for impromptu
peripheral hardware. U.S. Robotics wireless meetings in cafeterias, hallways, courtyards,
networking products offer a variety of solutions or wherever inspiration strikes while providing
to seamlessly integrate computers, peripherals, real-time LAN connectivity for business
and data. applications such as sending e-mail, working
on spreadsheets on shared drives, and
Wireless networking enables the same capabilities conducting market research.
and comparable speeds of a wired 10BASE-T
network without the difficulties associated with
laying wire, drilling into walls, or stringing Wireless LANs in the Home
Ethernet cables throughout an office building Wireless networking has become commonplace,
or home. Laptop users have the freedom to and with prices reduced to a fraction of what
roam anywhere in the office building or home they were, it is no wonder that wireless
without having to hunt down a connector cable networking products have transitioned from
or available jack. Every room in a wireless home the office and into the home. For the home
or office can be “connected” to the network, user, a wireless network provides freedom in
so adding more users and growing a network convenience and lifestyle to exchange words,
can be as simple as installing a new wireless data, and music or video with any computer –
network adapter. across the Internet, or around the world.
Home users can create a wireless network out
Reasons to choose wireless networking over
of an existing wired network and wirelessly
traditional wired networks include:
extend the reach of the Internet throughout
• Running additional wires or drilling new the home on multiple computers, making it
holes in a home or office could be prohibited more convenient for everyone to get online.
(because of rental regulations), impractical
(infrastructure limitations), or too expensive
• Flexibility of location and data ports is required

1

IEEE Wireless Networking time via different frequencies, providing more
resistance to radio frequency interference. The
Specifications 802.11a specification is also known as Wi-Fi5,
The IEEE (Institute of Electrical and Electronic and though regionally deployed, it is not a
Engineers) released the 802.11 specifications global standard like 802.11b.
in June 1999. The initial specification, known
as 802.11, used the 2.4 GHz frequency and 802.11b
supported a maximum data rate of 1 to 2 Mbps. The 802.11b standard (also known as Wi-Fi)
In late 1999, two new addenda were released. operates in the 2.4 GHz range with up to
The 802.11b specification increased the 11 Mbps data rates and is backward compatible
performance to 11 Mbps in the 2.4 GHz range with the 802.11 standard. 802.11b uses a
while the 802.11a specification utilized the technology known as complementary code
5 GHz range and supported up to 54 Mbps. keying (CCK) modulation, which allows for
Unfortunately, the two new specifications higher data rates with less chance of multi-path
were incompatible because they used different propagation interference (duplicate signals
frequencies. This means that 802.11a network bouncing off walls).
interface cards (NICs) and access points
U.S. Robotics 22 Mbps 802.11b
cannot communicate with 802.11b NICs and
access points. This incompatibility forced the Recent developments to 802.11b have seen
creation of the new draft standard known as numerous improvements to this well-established
802.11g. 802.11g supports up to 54 Mbps and and widely-deployed wireless standard. New
is interoperable with 802.11b products on the U.S. Robotics 22 Mbps products are designed
market today. The concern is that the 802.11g to support Packet Binary Convolutional Coding
specification is currently in development and (PBCC) in addition to CCK modulation. This
products will not be available until a later date. not only increases performance but also
maintains complete 802.11b compatibility with
both 11 Mbps and 22 Mbps products. The
802.11 Specifications overall benefits include:
The 802.11 specifications were developed • Up to twice the data rate of conventional
specifically for Wireless Local Area Networks 11 Mbps 802.11b standard products
(WLANs) by the IEEE and include four subsets
• Greater WLAN coverage: up to 70% greater
of Ethernet-based protocol standards: 802.11,
than standard 11 Mbps 802.11b products
802.11a, 802.11b, and 802.11g.
• Full interoperability with all 802.11b products:
802.11 works with 802.11b 11 Mbps, 802.11b
22 Mbps, and upcoming 802.11g products
802.11 operated in the 2.4 GHz range and was
the original specification of the 802.11 IEEE • Improved security over standard 802.11b:
standard. This specification delivered 1 to 2 Mbps 256-bit WEP encryption and MAC address
using a technology known as phase-shift keying authentication*
(PSK) modulation. This specification is no longer
used and has largely been replaced by other 802.11g
forms of the 802.11 standard. 802.11g is the most recent IEEE 802.11 draft
standard and operates in the 2.4 GHz range
802.11a with data rates as high as 54 Mbps over a limited
802.11a operates in the 5 - 6 GHz range with distance. It is also backward compatible with
data rates commonly in the 6 Mbps, 12 Mbps, 802.11b and will work with both 11 and 22 Mbps
or 24 Mbps range. Because 802.11a uses the U.S. Robotics wireless networking products.
orthogonal frequency division multiplexing 802.11g offers the best features of both 802.11a
(OFDM) standard, data transfer rates can be and 802.11b, but as of the publication date of
as high as 54 Mbps. OFDM breaks up fast this document, this standard has not yet been
serial information signals into several slower certified, and therefore is unavailable.
sub-signals that are transferred at the same

* MAC address authentication available with U.S. Robotics 22 Mbps Wireless Access Point and
U.S. Robotics 22 Mbps Wireless Cable/DSL Router.

2

All four standards are based on the CSMA/CA Direct Sequence Spread Spectrum
(Carrier Sense Multiple Access with Collision (DSSS)
Avoidance) Ethernet protocol for path sharing.
The most significant contribution of the 802.11 Direct sequence spread spectrum (DSSS)
specification is that it allows for interoperability technology breaks down the transmitted
among different vendors’ equipment. Thanks stream of data into small pieces across a
to the Wireless Ethernet Compatibility Alliance frequency channel. A redundant bit pattern
(WECA), 802.11 standard equipment will (known as a chipping code) is generated for
work together interchangeably, regardless each bit transmitted. Generally, the longer the
of the manufacturer. chipping code, the more likely it is that the
original transmitted data will be properly
received. DSSS technology uses more bandwidth
Different WLAN Technologies than FHSS, but DSSS is considered more reliable
and resists interference. Because of the chipping
As various wireless networking technologies code, data can still be recovered without
have advanced over time, several WLAN retransmission of the signal, even in the case
technologies have emerged, including: of damaged data bits. U.S. Robotics wireless
narrowband, spread spectrum, frequency networking products utilize DSSS technology.
hopping spread spectrum, and direct
sequence spread spectrum.
Wireless LAN Frequency Usage
Narrowband The 802.11b standard defines 14 frequency
As the name suggests, narrowband technology channels for use with this technology. Depending
uses a specific radio frequency (in the range on the country a user lives in and where he or
of 50 cps to 64 Kbps) for data transmission. she will be installing a WLAN, there are certain
governmental restrictions for companies offering
Spread Spectrum these products and consumers or businesses
deploying these products.
Originally developed for military use, spread
spectrum technology allows for greater In North America, the FCC (Federal
bandwidth by continually altering the frequency Communications Commission) and IC
of the transmitted signal, thus spreading the (Industry Canada) allow manufacturers and
transmission across multiple frequencies. users to use channels 1 through 11, per ETSI
Spread spectrum uses more bandwidth than approval (European Telecommunications
narrowband, but the transmission is more Standards Institute); most of Europe can use
secure, reliable, and easier to detect. channels 1 through 13, while in Japan, users
have all 14 channels available.
Frequency Hopping Spread Spectrum
(FHSS)
Channel Freq. US Canada Europe Spain France Japan
Frequency hopping spread spectrum (FHSS) (GHz) FCC IC ETSI
technology synchronizes the changing frequency 1 2.412 √ √ √ √
of both the transmitter and receiver (using a 2 2.417 √ √ √ √
narrowband carrier) to, in effect, produce a 3 2.422 √ √ √ √
single transmission signal. This frequency 4 2.427 √ √ √ √
“hopping” can occur as often as several times 5 2.432 √ √ √ √
a second; it is constantly changing from one 6 2.437 √ √ √ √
frequency to another, transmitting data for a 7 2.442 √ √ √ √
certain period of time before changing frequency 8 2.447 √ √ √ √
again. Like spread spectrum technology, FHSS 9 2.452 √ √ √ √
technology consumes additional bandwidth, 10 2.457 √ √ √ √ √ √
however, this is over the course of multiple 11 2.462 √ √ √ √ √ √
carrier frequencies. 12 2.467 √ √ √
13 2.472 √ √ √
14 2.484 √

Figure 1 – 802.11b channels and frequency per region

3

Even though there are 14 channel frequencies Ad Hoc (Peer-to-Peer) Mode vs.
available for use, it should be noted that the
actual channel frequency indicates the “center Infrastructure Mode
frequency” used by the transmitter and receiver The 802.11 specification defines two types
for communication. An 802.11b radio signal of operational modes: ad hoc (peer-to-peer)
consumes approximately 30 MHz of frequency mode and infrastructure mode. In ad hoc
spectrum, leaving a 5 MHz separation between mode, the wireless network is relatively simple
center frequencies. This means that the and consists of 802.11 network interface cards
signal extends out 15 MHz of the center (NICs). The networked computers communicate
frequency spectrum. directly with one another without the use of an
access point. In infrastructure mode, the wireless
network is composed of a wireless access point(s)
Center Frequency Center Frequency Center Frequency and 802.11 network interface cards (NICs). The
access point acts as a base station in an 802.11
network and all communications from all of the
2.417 2.422 2.427 2.432 2.442 2.447 2.452 2.457 2.467 2.472 wireless clients go through the access point.
The access point also provides for increased
Channel 1 Channel 6 Channel 11
wireless range, growth of the number of
wireless users, and additional network security.
2.412 2.437 2.462
5 MHz

15 MHz Ad Hoc Mode

30 MHz

Figure 2 – Bandwidth required for each 802.11 channel (also demonstrates the
5 MHz between each frequency)

As a result, the bandwidth required for each Independent Basic Service Set (IBSS)
channel signal overlaps several adjacent (ad hoc/peer-to-peer)
frequencies. This leaves the typical U.S. user
Figure 4 – Ad hoc mode
with three channels available for use by access
points (channels 1, 6, and 11) that are within
radio range of adjacent access points.
In ad hoc mode, also known as Independent
Basic Service Set (IBSS) or peer-to-peer mode,
all of the computers and workstations connected
with a wireless NIC card can communicate with
2.417 GHz 2.427 GHz 2.437 GHz 2.447 GHz 2.457 GHz 2.467 GHz each other via radio waves without an access
Channel 5 Channel 10 point. Ad hoc mode is convenient for quickly
Channel 4 Channel 9 Channel 14 setting up a wireless network in a meeting
Channel 3 Channel 8 Channel 13 room, hotel conference center, or anywhere else
Channel 2 Channel 7 Channel 12 sufficient wired infrastructure does not exist.
Channel 1 Channel 6 Channel 11

2.412 GHz 2.422 GHz 2.432 GHz 2.442 GHz 2.452 GHz 2.462 GHz 2.472 GHz 2.484 GHz

Figure 3 – Shows an example of overlapping frequencies —
802.11b bandwidth allocation

4

LAN

Access Point Access Point

Infrastructure Mode
(Basic Service Set [BSS])

Multiple Infrastructure Setups
(Extended Service Set [ESS])

Figure 5 – Basic Service Set (BSS) and Extended Service Set (ESS)

Infrastructure Mode
In infrastructure mode, all mobile and wireless client workstation networking loads can be
client devices and computers communicate with better balanced. A wireless LAN NIC may decide
the access point, which provides the connection to “reassociate” itself with another access point
from the wireless radio frequency world to within range because the load on its current
the hard-wired LAN world. The access point access point is too high for optimal performance.
performs the conversion of 802.11 packets These capabilities can have a positive impact on
to 802.3 Ethernet LAN packets. Data packets overall network performance.
traveling from the LAN to a wireless client are
converted by the access point into radio signals
and transmitted out into the environment. All
wireless clients and devices within range can
receive the packets, but only those clients with
the appropriate destination address will receive
and process the packets.

A basic wireless infrastructure with a single
access point is called a Basic Service Set (BSS).
When more than one access point is connected
to a network to form a single sub-network, it
is called an Extended Service Set (ESS).

The 802.11 specification includes roaming
capabilities that allow a client computer to
roam among multiple access points on different
channels. Thus, roaming client computers with
weak signals can associate themselves with
other access points with stronger signals.
Alternately, by setting up multiple access points
to cover the same geographic area and by Figure 6 – Roaming among access points with non-overlapping frequencies
using different non-overlapping frequencies, allows for virtually unlimited coverage range

5

Wireless Network Components Router
Much like a traditional wired LAN, a WLAN A router is a device used for sharing a single
is a grouping of computers and peripheral Internet connection across multiple computers.
devices that share a common communications This is ideal in the home or office where
backbone. As is implied by the name, a WLAN multiple computers and devices can be online
allows users to connect to the LAN wirelessly at the same time with only a single Internet
via radio transmission. The following are the connection. The U.S. Robotics 22 Mbps
most common components of a WLAN. Wireless Cable/DSL Router includes built-in
wireless access point capabilities.
Access Point Wireless networking users should keep the
The access point is a device that links a following in mind:
wireless network to a wired LAN. It increases • One wireless PC card (U.S. Robotics 22 Mbps
the effective range of a wireless network and Wireless PC Card, model 2210) is needed
provides additional network management and for each laptop and one wireless PCI adapter
security features. Wireless networks of three or (U.S. Robotics 22 Mbps Wireless PCI Adapter,
fewer PCs do not require an access point for model 2215 or 2216) is needed for each
ad hoc networking. Access points are useful desktop computer to be wirelessly networked.
for larger networks, and they are particularly
well-suited for adding wireless capability to an • An ad hoc network of up to three computers
existing wired network. can be created with wireless PC cards or PCI
adapters. To connect more than three com-
The U.S. Robotics 22 Mbps Wireless Access puters, include an access point or router
Point connects via an RJ-45 cable to a LAN (U.S. Robotics 22 Mbps Wireless Access
and can support up to 20 wireless users at Point, model 2249, or U.S. Robotics 22 Mbps
an effective range of up to 1500 feet in open Wireless Cable/DSL Router, model 8022) in
spaces. It also enables additional security the network design.
features such as MAC address authentication. • Ad hoc wireless networks using U.S. Robotics
22 Mbps wireless networking products have
PC Card an effective range of up to 300 feet in any
A wireless PC card enables laptop users to direction, indoors or out, and even on different
connect wirelessly to the LAN. U.S. Robotics levels of a building. As with any wireless
22 Mbps Wireless PC Cards allow for ad product, ad hoc networks work best when
hoc networking of up to three computers closer together and in an open environment.
at an effective range of up to 1000 feet in • Wireless networks that use either a
open spaces U.S. Robotics 22 Mbps Wireless Access
Point or a U.S. Robotics 22 Mbps Wireless
PCI Adapter Cable/DSL Router have an effective
range of up to 1500 feet, with the same
Just as a wireless access PC card allows portable
considerations as ad hoc networks.
and laptop computers access to the LAN, a
wireless access PCI adapter allows desktop PC • Sharing Internet access among multiple
users access to the LAN. U.S. Robotics 22 Mbps computers or laptops requires a router. The
Wireless PCI Adapters allow for ad hoc U.S. Robotics 22 Mbps Wireless Cable/DSL
networking of up to three computers at an Router is capable of supporting up to 253
effective range of up to 1000 feet in open spaces. clients (with additional hardware) for wired
and wireless Internet sharing.

6

WLAN Performance Depending on environmental specifics, automatic
downshifting by the access point or client
Much the same way a cordless phone works allows compatibility adjustment to prevailing
better when it is close to its base, wirelessly radio frequency conditions. At any one
networked computers function best when moment, an 802.11b network can be running
located relatively close together and in open at 11 Mbps, 5.5 Mbps, 2 Mbps, or 1 Mbps
sight of each other. The level of performance 22 Mbps wireless networking products). And
of an 802.11 WLAN is dependent on a number depending on where each wireless device is
of important environmental and product-specific in a home or office, each of those devices can
factors. Access points will automatically negotiate be transmitting at any one of these speeds.
the appropriate signaling rate based upon Typically, the software applications that ship
environmental conditions, such as: with an 802.11 NIC adapter are capable of
• Distance between WLAN devices reporting current connection speeds and also
(AP and NICs) allow users to perform site surveys for the
• Transmission power levels best location of an access point.
• Building and home materials
The diagram below shows how distance and
• Radio frequency interference building materials can impact the performance
• Signal propagation of an 802.11 network.
• Antenna type and location
Distance Between WLAN Devices

Pool
Outside
Kitchen
Family
Room Home
Office
1
2
1 5.5 11
2
5.5
11 22 WLAN

Master
Bedroom

Living
Room Bedroom

= Standard 11 Mbps 802.11b product

= U.S. Robotics’ 22 Mbps 802.11b product

Figure 7 – Effects of distance on the 802.11 signal

7

(Access Points and NICs) The wood, metal, and other building materials
have a direct impact on signal propagation
Typically, published wireless range claims are and absorption. Other factors include:
for line-of-sight or open area environments • Multi-path interference: This occurs when
such as cafeterias, auditoriums, or other areas signal strength and timing are altered due to
that lack interference-causing obstacles. The the signal reflecting off walls, filing cabinets,
following chart provides a quick comparison beams, and other objects. This results in a
of conventional 802.11b wireless products against device receiving two or more identical signals.
U.S. Robotics 22 Mbps wireless products in • Fading: Fading is the reduced amplitude of
a real-world application with typical levels a signal as a result of passing through radio-
of interference and common obstructions, transparent objects such as walls and ceilings.
such as walls and other physical barriers. • Dead zones: Locations where radio signals
U.S. Robotics 22 Mbps maximum sustainable never reach due to reflections, obstructions,
throughput is clearly superior to that of or other environmental conditions.
standard 11 Mbps 802.11b.
The new 22 Mbps line of U.S. Robotics
wireless networking products are specifically
11 Mbps Products U.S. Robotics 22 Mbps Products
designed for optimal use in the home with
~8 Mbps @ 200 ft ~13.5 Mbps @ 200 ft
minimal degradation in signal quality due
~4.5 Mbps @ 250 ft ~8 Mbps @ 250 ft to environmental conditions; U.S. Robotics
~2 Mbps @ 300 ft ~6 Mbps @ 300 ft wireless products are designed to work
~1 Mbps @ 325 ft ~4.25 Mbps @ 325 ft through walls instead of around them.
N/A ~4 Mbps @ 350 ft

Radio Frequency Interference
Products designed to work with the 802.11a
standard have a faster data rate, but the signal Varying amounts of radio interference exist all
is limited in distance and susceptible to around us. A savvy wireless user can minimize
environmental conditions like rain and fog. this interference to maximize the performance
Because of these limitations, 802.11a products of his or her WLAN. But before a user can
are more practical for indoor applications, will begin to minimize these points of interference,
most likely require additional access points for he or she must begin to recognize the more
proper area coverage, and will achieve lower common causes.
data rates than the maximum allowed. The 802.11b standard uses the unlicensed
radio spectrum that is commonly shared by
a variety of consumer devices: baby monitors
Transmit Power Levels and cameras, 2.4 GHz cordless phones,
Most WLAN devices have a power output of microwave ovens, and Bluetooth-enabled
only 30 mW, which is far less then a typical devices like cellular phones or personal digital
cellular phone or walkie-talkie. assistants (PDAs). These devices transmit in
the 2.4 GHz range and can impact WLAN
performance. DSSS technology, as used in
Power Consumption Levels U.S. Robotics 22 Mbps wireless networking
Most 802.11b NICs allow the user to customize products, is very effective at minimizing
the power modes in the software drivers in these types of interference.
order to optimize WLAN performance versus
battery life for a notebook system. A quick scan around a user’s home or
business will tell if there are any potential
problems. Using products designed to work
Building and Home in the 900 MHz frequency can help minimize
any interference and maximize the
Materials/Signal Propagation performance of any WLAN.
The contents of a home or office building can
have a dramatic impact on the quality of the
signal obtained with an 802.11 wireless network.

8

Antenna Type and Location Bluetooth vs. 802.11b
There are two general types of antennas Those unfamiliar with wireless technology
used for 802.11: directional and omnidirectional. commonly confuse 802.11b and Bluetooth
A directional antenna concentrates energy in technologies. Both technologies use the
a narrow conic path when sending and rejects 2.4 GHz radio frequency for wireless
signals outside a single direction when receiving. communications; however, the goal, focus,
An omnidirectional antenna transmits in a 360
o and concept of Bluetooth is different from
arc and is capable of receiving signals from 802.11b wireless networking.
any direction. Most 802.11b devices implement
Bluetooth technology is focused on replacing
an omnidirectional antenna. The antenna type
the short cables used to connect consumer
and location are important factors when
electronic devices such as keyboards, mouse
setting up a wireless network. Users should
devices, personal digital assistants (PDAs),
experiment with several locations for their
computers, printers, and cellular phones. This
access point and antenna in order to determine
type of close proximity connectivity is often
the optimal location for maximum performance.
referred to as a Wireless Personal Area
Network (WPAN).
Aggregating Bandwidth Bluetooth devices differ from 802.11b in a
For businesses looking to increase performance number of ways. Bluetooth is not a “true
and for supporting dozens of devices in close networking” standard in the manner that
proximity, it is possible to overlap access Wi-Fi is, and its range is limited to approxi-
points to provide an aggregate bandwidth to mately 10 to 30 feet (3 m to 9.1 m) with a
all of the wireless clients. This can be achieved raw data rate of 1 Mbps/723 Kbps available.
by setting the access points to non-overlapping Bluetooth also limits the maximum number
frequencies for the covered area. of separate 1 MHz simultaneous connections
(devices) to seven at a single time.

Since Wi-Fi was designed for higher through-
put and a multi-user environment, the two
technologies have their own unique places
in home and office environments. Technical
details about Bluetooth are beyond the scope
of this document, and additional information
can be found at http://www.bluetooth.com.

Wireless Security
annel 11 Security is an obvious concern with any network,
wired or wireless. Because communication over
Channel 6 a traditionally wired network is, by its very
nature, over physical wires, security is often
built into the physical environment itself. WLANs
Channel 1
operate over radio signals, so the same security
measures cannot be assumed. For many wireless
users, the enabling of the built-in security
known as Wireless Equivalent Privacy (WEP) is
sufficient for their home or small to medium
office WLAN. WEP uses 64- and 128-bit
encryption and is the cipher scheme designated
Figure 8 – Aggregating access points to provide more for use in 802.11b networking. U.S. Robotics
available bandwidth 22 Mbps wireless products include enhanced
256-bit WEP encryption that is not commonly

9

Internet

U.S. Robotics Wireless
Access Point

with DHCP enabled on a WLAN, and without
Router
proper security measures enabled, a user can
Access Point
connect automatically to the network.

Ethernet
Firewall
Change Subnet Default: Some access points
Switches default to the IP subnet of 192.168.x.x. When
Access Point
disabling DHCP and using static IP addresses,
users should also change their default IP
subnet value.

Move Access Point in Front of Firewalls or
DMZs: The best solution for keeping prying
eyes away from a corporate network is to
move the access point off of the corporate
Figure 9 – Locating an access point off of a corporate LAN LAN and in front of a firewall or on a DMZ
(demilitarized zone) port. With the access
available in the 802.11b standard. WEP encrypts
point in front of a firewall, intruders will
the data transmitted over a WLAN, protecting
not have access to the corporate LAN. All
the once vulnerable communication between
corporate wireless users will require the
the client and access point. When combined
installation and use of a virtual private network
with traditional security measures (password
(VPN) client to create a secure tunnel into the
protection, authentication, encryption, virtual
corporate LAN. This may require additional
private networks), WEP can be very effective.
administrative support from IT personnel, but
For business and enterprise users, network the extra security is well worth the effort.
and data security is of the utmost concern. To
In addition to offering standard 64- and 128-bit
address this, there are a number of common
WEP encryption, the U.S. Robotics family of
precautions that a WLAN user can take to limit
22 Mbps wireless products also offers the added
a network to hacker attacks, vandalism, and
security of 256-bit encryption for improved
corporate espionage.
security over conventional 11 Mbps wireless
Change Common Passwords Frequently: products to protect against hackers while
Most of the top manufacturers have default maintaining maximum performance. The
passwords for all of their equipment. Users U.S. Robotics 22 Mbps Wireless Access Point
should be diligent in changing any default and 22 Mbps Wireless Cable/DSL Router also
passwords and to change them on a regular include the added security of built-in MAC
basis in order to avoid detection. address authentication for even more local
network protection.
Limit MAC Addresses: Some access points
allow users to specify exactly which Media
Access Control (MAC) addresses can communi-
Internet
cate with the network. A MAC address is a
hardware address that uniquely identifies each
node of a network. Every network adapter in
the world has a unique MAC address. By
strictly specifying only those MAC addresses
that can attach to a network, unauthorized
users can be denied access.
Model-2210
22 Mbps Wireless Model-2215
Disable DHCP: By default, some access PC Card 22 Mbps Wireless
PCI Adapter
points respond directly to Dynamic Host
Configuration Protocol (DHCP) requests or
allow the forwarding of DHCP requests from
Router
clients. DHCP is a protocol for assigning IP Cable/DSL Modem Model-2210
Model-2249 22 Mbps Wireless
addresses dynamically on a network. However, 22 Mbps Wireless PC Card
Access Point

Figure 10 – Locating an Access Point off of a Home LAN

10

802.11
Committees Standard Definition
U.S. Robotics Wireless Solutions 802.11 1 to 2 Mbps using 2.4 GHz frequency
802.11a Up to 54 Mbps using 5 GHz frequency
With the world's number-one selling modem 802.11b Up to 11 Mbps using 2.4 GHz frequency with standard 802.11b
brand, U.S. Robotics has the most recognized equipment
Up to 22 Mbps with U.S. Robotics Packet Binary Convolutional Code
product line in its category within the Internet (PBCC) 22 Mbps technology
access industry. Millions of computer users 802.11c Support for wireless bridge operations
around the globe first connected to the Internet 802.11d Support for improving operations in markets currently not
with a U.S. Robotics analog modem. U.S. Robotics served by the standard
The IEEE 802.11 Committees below are still in the standard
has extended its reputation for providing quality, developmental stages.
reliability, and technically innovative products 802.11e Developing an Ethernet quality of service over wireless
to a new line of wireless networking solutions 802.11f Developing multi-vendor access point roaming features
for home and office networking applications. 802.11g Developing >20 Mbps and up to 54 Mbps wireless using 2.4 GHz
802.11h Developing a uniform standard for transmission and power usage
These new products include a complete family
802.11i Developing a new security protocol
of 22 Mbps wireless networking products 802.11h Developing spectrum managed 802.11a
that provide faster speeds, greater range, and 802.1x Developing a version of the extended authentication protocol
better area coverage than conventional (EAP) applicable to wireless networking
11 Mbps products.
For additional information on IEEE wireless activity, standards, and development, visit the
U.S. Robotics 22 Mbps wireless networking IEEE Web site at: http:// standards.ieee.org/ wireless/.
products are fully compatible with all IEEE
with built-in wireless access point can be added
802.11b 11 Mbps and 22 Mbps wireless products
easily to an existing LAN – wired or wireless.
and will automatically adjust to the fastest rate
To network more than 20 computers, include
possible: 11 Mbps or 22 Mbps. This means that
multiple U.S. Robotics 22 Mbps Wireless Access
networks can easily incorporate a combination
Points or 22 Mbps Wireless Cable/DSL Routers.
of both 11 Mbps and 22 Mbps wireless products.
These two products increase the effective range
In fact, all U.S. Robotics 22 Mbps wireless net-
of a wireless network from 1000 feet to 1500 feet
working products are forward compatible and
in any direction – even outside or on different
designed to work with the upcoming 802.11g
levels of a building.
standard when it becomes available. So, whether
a wireless client is using the latest 22 Mbps The U.S. Robotics 22 Mbps Wireless Cable/DSL
gear, a combination of 11 Mbps and 22 Mbps, Router not only includes the functionality of
or plans on adding the next standard when it a 22 Mbps Wireless Access Point, but it also
becomes available, U.S. Robotics wireless includes router capabilities for sharing high-speed
networking solutions can continue to play Internet access among multiple users spread
an integral role in any network. throughout a household or office building.
For simple ad hoc networking of up to three All U.S. Robotics 22 Mbps wireless networking
computers, a user simply installs the software, products offer numerous benefits and
plugs a U.S. Robotics 22 Mbps Wireless PCI conveniences that can be applied to SOHO
Adapter (Model 2215 or 2216) into each desktop (Small Office/Home Office) users, computing
PC or a U.S. Robotics 22 Mbps Wireless PC environments requiring flexibility, and even
Card (Model 2210) into each laptop’s available existing legacy networks. The IEEE 802 standard
PC card slot, and starts sharing Internet access, supports the same network configuration options
files, and printers at speeds up to 22 Mbps. of legacy Ethernet LANs, which allows for a
U.S. Robotics adapters can support any variety of applications and solutions.
combination of up to three 22 Mbps Wireless
PC Cards and 22 Mbps Wireless PCI Adapters U.S. Robotics continues to develop solutions to
when in ad hoc mode. Security is maintained provide data access to both business professionals
through 64-, 128-, and 256-bit Wired Equivalent and home users. U.S. Robotics wireless networking
Privacy (WEP) encryption for improved security solutions are built upon proven technology and
over 11 Mbps wireless products. backed by an organization that is committed to
the highest standards of product quality and
For larger networks (up to 20 computers for customer satisfaction. These wireless networking
an Access Point or Wireless Router) and for solutions from U.S. Robotics represent just some
enhanced security features like MAC address of the latest developments in keeping people
authentication, a U.S. Robotics 22 Mbps Wireless connected worldwide – with information,
Access Point (Model 2249) or a U.S. Robotics entertainment, and each other.
22 Mbps Wireless Cable/DSL Router (Model 8022)

11

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