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 Questions
Section One - Wireless Networking
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What is wireless networking?
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What is a wireless network made up of?
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What is IEEE 802.11?
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Can I mix wireless equipment from different vendors?
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If my computer is connected to a wireless LAN, can it communicate with
computers on a wired LAN as well?
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What is the range of a wireless network?
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How many wireless networked computers can use a single access point?
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Can I have more than one access point?
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What is Roaming?
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How can I use a wireless network to interconnect two LANs?
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Is it true that wireless networking is only good for laptop computers?
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What about security?
Section Two - Wireless Networking and the Internet
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How can I use a wireless network to share an Internet connection?
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If I have more than one hardware access point, how can I share a
single Internet connection?
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If I use a wireless network to connect to the Internet does my ISP
need a wireless network too?
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Can networking software identify a wireless computer in the same way
it can identify an ethernet computer on the network?
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Answers
Section One - Wireless Networking
1. What
is wireless networking?
The term wireless networking refers to
technology that enables two or more computers to communicate using
standard network protocols, but without network cabling. Strictly
speaking, any technology that does this could be called wireless
networking. The current buzzword however generally refers to wireless
LANs. This technology, fuelled by the emergence of cross-vendor industry
standards such as IEEE 802.11, has produced a number of affordable
wireless solutions that are growing in popularity with business and
schools as well as sophisticated applications where network wiring is
impossible, such as in warehousing or point-of-sale handheld equipment.
2.
What
is a wireless network made up of?
There are two kinds of wireless networks:
a.
An ad-hoc, or peer-to-peer wireless network
consists of a number of computers each equipped with a wireless networking
interface card. Each computer can communicate directly with all of the
other wireless enabled computers. They can share files and printers this
way, but may not be able to access wired LAN resources, unless one of the
computers acts as a bridge to the wired LAN using special software. (This
is called "bridging")
Figure
1: Ad-Hoc or Peer-to Peer Networking.
Each computer with a wireless interface can
communicate directly with all of the others.
b.
A
wireless network can also use an access point, or base station. In this
type of network the access point acts like a hub, providing connectivity
for the wireless computers. It can connect (or "bridge") the wireless LAN
to a wired LAN, allowing wireless computer access to LAN resources, such
as file servers or existing Internet Connectivity.
There are two types of
access points:
i.
Dedicated hardware access points (HAP) such as Lucent's WaveLAN, Apple's
Airport Base Station or WebGear's AviatorPRO. (See
Figure 2). Hardware access points offer comprehensive support of most
wireless features, but check your requirements carefully.
ii.
Software Access Points which run on a computer equipped with a wireless
network interface card as used in an ad-hoc or peer-to-peer wireless
network. (See
Figure 3) The Vicomsoft InterGate suites are software routers that can
be used as a basic Software Access Point, and include features not
commonly found in hardware solutions, such as Direct PPPoE support and
extensive configuration flexibility, but may not offer the full range of
wireless features defined in the 802.11 standard.
With appropriate networking
software support, users on the wireless LAN can share files and printers
located on the wired LAN and vice versa. Vicomsoft's solutions support
file sharing using TCP/IP.
Figure 2: Hardware
Access Point.
Wireless connected computers using a
Hardware Access Point.
Figure 3: Software Access
Point.
Wireless connected computers using a
Software Access Point.
3.
What is IEEE
802.11?
Wireless networking hardware requires the
use of underlying technology that deals with radio frequencies as well as
data transmission. The most widely used standard is 802.11 produced by the
Institute of Electrical and Electronic Engineers (IEEE). This is a
standard defining all aspects of Radio Frequency Wireless networking.
4.
Can I mix
wireless equipment from different vendors?
Because most wireless networking hardware
vendors support the 802.11 standard they can inter operate. However, we
recommend verification as the standard is a fairly recent one, and does
specify two different methods for wireless communications; Frequency
Hopping (FH) and Direct Sequence Spread Spectrum (DSSS or DS), which are
not interoperable.
When purchasing wireless networking hardware from separate vendors be sure
to obtain guarantees from the vendors that the hardware will interoperate
and follows the standards.
Within a short time we expect all new wireless cards, like ethernet cards,
to become inexpensive, ubiquitous and totally interoperable.
Also of note is that the latest version of the standard defines 11mbps and
5.5mbps networking, with support for the older standard 1mbps and 2mbps
speeds. This provides some compatibility with different or older
equipment. Note that this new standard covers DS-type Networks, not FH
types.
Software access points such as InterGate which uses the wireless interface
of the host computer should have no compatibility issues with third party
wireless hardware, as long as standards are followed. Typically wireless
hardware is identified to the software as a network interface, and
therefore can be used in the same way as any other network card.
5.
If my computer is
connected to a wireless LAN, can it communicate with computers on a wired
LAN as well?
To do this you will need some sort of
bridge between the wireless and wired network. This can be accomplished
either with a hardware access point or a software access point. Hardware
access points are available with various types of network interfaces, such
as Ethernet or Token Ring, but typically require extra hardware to be
purchased if your networking requirements change.
If networking requirements go beyond just interconnecting a wired network
network to a small wireless network, a software access point may be the
best solution.
A software access point does not limit the type or number of network
interfaces you use. It may also allow considerable flexibility in
providing access to different network types, such as different types of
Ethernet, Wireless and Token Ring networks. Such connections are only
limited by the number of slots or interfaces in the computer used for this
task.
Further to this the software access point may include significant
additional features such as shared Internet access, web caching or content
filtering, providing significant benefits to users and administrators.
6.
What is the range
of a wireless network?
Each access point has a finite range within
which a wireless connection can be maintained between the client computer
and the access point. The actual distance varies depending upon the
environment; manufacturers typically state both indoor and outdoor ranges
to give a reasonable indication of reliable performance. Also it should be
noted that when operating at the limits of range the performance may drop,
as the quality of connection deteriorates and the system compensates.
Typical indoor ranges are 150-300 feet, but can be shorter if the building
construction interferes with radio transmissions. Longer ranges are
possible, but performance will degrade with distance.
Outdoor ranges are quoted up to 1000 feet, but again this depends upon the
environment.
There are ways to extend the basic operating range of Wireless
communications, by using more than a single access point or using a
wireless relay /extension point. See
Question 8 for further information.
7.
How many wireless
networked computers can use a single access point?
This depends upon the manufacturer. Some
hardware access points have a recommended limit of 10, with other more
expensive access points supporting up to 100 wireless connections. Using
more computers than recommended will cause performance and reliability to
suffer.
Software access points may also impose user limitations, but this depends
upon the specific software, and the host computer's ability to process the
required information.
8.
Can I have more
than one access point?
Yes, multiple access points can be
connected to a wired LAN, or sometimes even to a second wireless LAN if
the access point supports this.
In most cases, separate access points are interconnected via a wired LAN,
providing wireless connectivity in specific areas such as offices or
classrooms, but connected to a main wired LAN for access to network
resources, such as file servers. (See
Figure 4)
Figure 4: Multiple Access Points.
Wireless connected computers using Multiple
Access Points.
If a single area is too large to be covered
by a single access point, then multiple access points or extension points
can be used. -- Note that an "extension point" is not defined in the
wireless standard, but have been developed by some manufacturers. When
using multiple access points, each access point wireless area should
overlap its neighbors. This provides a seamless area for users to move
around in using a feature called "roaming. " (See the next question for an
explanation of Roaming)
Some manufacturers produce extension points, which act as wireless relays,
extending the range of a single access point. Multiple extension points
can be strung together to provide wireless access to far away locations
from the central access point. (See
Figure 5)
Figure 5: Extension Point.
Wireless connected computers using an Access Point with an Extension
Point.
9.
What
is Roaming?
A wireless computer can "roam" from one
access point to another, with the software and hardware maintaining a
steady network connection by monitoring the signal strength from in-range
access points and locking on to the one with the best quality. Usually
this is completely transparent to the user; they are not aware that a
different access point is being used from area to area. Some access point
configurations require security authentication when swapping access
points, usually in the form of a password dialog box.
Access points are required to have overlapping wireless areas to achieve
this as can be seen in the following diagram:
Figure 6: Roaming.
A user can move from Area 1 to Area 2
transparently. The Wireless networking hardware automatically swaps to the
Access Point with the best signal.
Not all access points are capable of being configured to support roaming.
Also of note is that any access points for a single vendor should be used
when implementing roaming, as there is no official standard for this
feature.
10.
Can I use a
wireless network to interconnect two LANs?
Yes. Wireless networking offers a
cost-effective solution to users with difficult physical installations
such as campuses, hospitals or businesses with more than one location in
immediate proximity but separated by public thoroughfare. This type of
installation requires two access points. Each access point acts as a
bridge or router connecting its own LAN to the wireless connection. The
wireless connection allows the two access points to communicate with each
other, and therefore interconnect the two LAN's.
Figure 7: LAN to LAN Wireless Communications
A Hardware Access Point providing wireless
connectivity to local computers and a software access point. The software
access point provides Wired Ethernet network 2 computers access to Wired
Network 1.
Note that not all hardware access points
have the ability to directly interconnect to another hardware access
point, and that the subject of interconnecting LAN's over wireless
connections is a large and complex one, and is beyond the scope of this
introduction. See the
reference links at the end of this section if you require further
information.
11.
Is it true that
wireless networking is only good for laptop computers?
Although wireless networking offers obvious
benefits to users of laptops who move from location to location throughout
the day, there are benefits for users of fixed position computers as well:
Many schools and businesses have unsuitable building layouts or walls that
cannot be wired for various reasons making it difficult or impossible to
build a wired network. Wireless networking in these environments is a very
cost effective alternative also providing future flexibility.
In cases where a small number of computers are separated from a main
network a wireless link may be more cost effective than network cabling
although the latter is perfectly feasible.
Temporary wireless LANs can easily be created for exhibitions, school or
business projects, all without any trailing cabling.
12.
What
about security?
Wireless communications obviously provide
potential security issues, as an intruder does not need physical access to
the traditional wired network in order to gain access to data
communications. However, 802.11 wireless communications cannot be received
--much less decoded-- by simple scanners, short wave receivers etc. This
has led to the common misconception that wireless communications cannot be
eavesdropped at all. However, eavesdropping is possible using specialist
equipment.
To protect against any potential security issues, 802.11 wireless
communications have a function called WEP (Wired Equivalent Privacy), a
form of encryption which provides privacy comparable to that of a
traditional wired network. If the wireless network has information that
should be secure then WEP should be used, ensuring the data is protected
at traditional wired network levels.
Also it should be noted that traditional Virtual Private Networking (VPN)
techniques will work over wireless networks in the same way as traditional
wired networks.
Section Two - Wireless Networking and the Internet
13.
How
can I use a wireless network to share an Internet connection?
Once you realise that wireless cards are
analogous to ethernet cards and that empty space is analogous to ethernet
cabling, the answer to this question becomes clear. To share an Internet
connection across a LAN you need two things:
· an
Internet sharing hardware device or software program
·
a LAN
If your LAN is wireless, the same criteria
apply. You need a hardware or software access point and a wireless LAN.
Any computer equipped with a wireless network card running suitable
Internet sharing software can be used as a software access point. (See
Figure 8) A number of vendors offer hardware access points.
A hardware access point may provide Internet Sharing capabilities to Wired
LAN computers, but does not usually provide much flexibility beyond very
simple configurations. (See
Figure 9)
Figure 8: Software Access Point.
Wireless connected computers using a
Software Access Point for shared Internet access.
Figure 9: Hardware Access Point.
Wireless connected computers using a Hardware Access Point for shared
Internet access.
14.
If I have more
than one hardware access point, how can I share a single Internet
connection?
If an existing wired LAN already has an
Internet connection, then the hardware access points simply connect to
your LAN and allow wireless computers to access the existing Internet
connection in the same way as wired LAN computers.
Figure 10: Multiple Access Points.
Wireless connected computers using Multiple Access Points.
If there is no existing Internet connection, then this depends on the
access point:
Figure 11: Software Access Point sharing one Internet connection.
Wireless connected computers using Multiple Access Points. All wired and
wireless computers access the Internet through a single software access
point.
If an access point provides some form of
Internet sharing itself, then having multiple such access points connected
to a wired LAN may require some special configuration, or possibly may
require an additional Internet sharing device or software program.
15.
If I use a
wireless network to connect to the Internet does my ISP need a wireless
network too?
If you use a wireless network to connect to
the Internet, the wireless part only concerns your LAN. The communications
link from your LAN to your Internet service provider (ISP) would be
identical whether or not you had a wireless network. For example, if you
connected an Ethernet network to the Internet via a 56K modem, when you
upgraded your network to use wireless, you would still use the same 56K
modem to connect to the Internet.
16.
Can networking
software identify a wireless computer in the same way it can identify an
Ethernet computer on the network?
Wireless cards look just like Ethernet
cards to your network drivers. In fact, wireless networking cards have
unique MAC hardware addresses that are formatted like ethernet hardware
addresses allocated from the same standards organization.
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