ZyXEL Communications ZyAIR G-5100 Manual

ZyAIR G-5100 Support Notes
V3.50(HV.0) | 2005.6.30
FAQ
-ZyNOS FAQ
-Product FAQ
- Wireless FAQ
Application Notes
-Infrastructure Mode
-Wireless MAC Address Filtering
-WEP Configurations
-Roaming
-Site Survey
-Repeater mode
-AP + Bridge mode
-802.1x/WPA
CI Command List
Trouble Shooting

ZyNOS FAQ
1. What is ZyNOS?
2. How do I access the embeded web configurator?
3. What is the default username and password? Moreover, how do I
change it?
4. How do I upload the ZyNOS firmware code via embedded web
configurator?
5. How do I upgrade/backup the ZyNOS firmware by using TFTP client
program via LAN?
6. How do I upgrade/backup the ZyNOS firmware by using FTP client
program via LAN?
7. How do I upload or backup ROMFILE via web configurator?
8. How do I backup/restore configurations by using TFTP client program
via LAN?
9. How do I backup/restore configurations by using FTP client program
via LAN?
1. What is ZyNOS?
ZyNOS is ZyXEL's proprietary Network Operating System. It is the platform
on all ZyXEL device that delivers network services and applications. It is
designed in a modular fashion so it is easy for developers to add new features.
New ZyNOS software upgrades can be easily downloaded from our FTP sites
as they become available.
2. How do I access the embeded web configurator?
The Web configurator is configuration interface via user's web browser, which

can be access by typing in the IP address of the ZyAIR G-5100 in users web
browser. To access the ZyAIR G-5100's web configurator via web browser,
the configuration PC must be in the same IP segment of ZyAIR G-5100 and
ZyAIR G-5100 must be reachable to the configuration station.
3. What is the default username and password? Moreover, how do I
change it?
The default username is "admin" and can not be changed, the default password
is 1234. You can change the password once you enter the web configuration
menu under "ADVANCED"->"SYSTEM" and press the Password tab. At the
password screen type in the old password and the new password and retype to
confirm than press "Apply" button to save the change.
4. How do I upload the ZyNOS firmware code via embeded web
configurator?
The procedure for uploading ZyNOS via embeded web configurator is as
follows.
a. Log on into the web configurator
b. Press "MAINTENANCE" from the left menu.
c. Press "F/W Upload" from the left menu.
d. Press "browse" button and point to the directory where the firmware you
want to upload is kept and press "Upload" button
e. It will prompt you the firmware is upload successful and ZyAIR G-5100
will reboot.
5. How do I upgrade/backup the ZyNOS firmware by using TFTP client
program via LAN?
The ZyAIR G-5100 allows you to transfer the firmware from/to ZyAIR G-5100
by using TFTP program via LAN. The procedure for uploading ZyNOS via
TFTP, FTP is as follows.
a. Use the TELNET client program in your PC to login to your Prestige.

b. Enter CI command 'sys stdio 0' in menu 24.8 to disable console idle
timeout
c. To upgrade firmware, use TFTP client program to put firmware in file
'ras' in the ZyAIR G-5100. After data transfer is finished, the Prestige
will program the upgraded firmware into FLASH ROM and reboot itself.
d. To backup your firmware, use the TFTP client program to get file 'ras'
from the ZyAIR G-5100.
6. How do I upgrade/backup the ZyNOS firmware by using FTP client
program via LAN?
The ZyAIR G-5100 allows you to transfer the firmware from/to ZyAIR G-5100
by using FTP program via LAN. The procedure for uploading ZyNOS via FTP
is as follows.
a. Use the TELNET client program in your PC to login to your Prestige.
b. To upgrade firmware, use FTP client program to put firmware in file
'ras' in the ZyAIR G-5100. After data transfer is finished, the Prestige
will program the upgraded firmware into FLASH ROM and reboot itself.
c. To backup your firmware, use the FTP client program to get file 'ras'
from the ZyAIR G-5100.
7. How do I upload or backup ROMFILE via web configurator?
In some situations, you may need to upload the ROMFILE, restore to previous
saved configuration, or the need of resetting SMT to factory default.
The procedure for uploading ROMFILE via the web configurator is as follows.
a. Log on into the Web Configurator
b. Press "MAINTENANCE" from the left menu.
c. Press "Configuration" from the left menu.
d. Press "Restore" tab and press browse button point to the directory where
the romfile you want to upload is stored.
e. Press "Upload" button.
The procedure for backup ROMFILE via the Web Configurator is as follow

a. Log on into the Web Configurator
b. Press "MAINTENANCE" from the left menu.
c. Press "Configuration" from the left menu.
d. Press "Backup" tab and press "Backup" button, a pop up windows will
ask you where to store the back up ROMFILE.
e. Press "Save file" and browse to where you want the file be save.
f. Press "Save" button.
8. How do I backup/restore configurations by using TFTP client program
via LAN?
a. Use the TELNET client program in your PC to login to your ZyAIR G-
5100.
b. Enter CI command 'sys stdio 0' in menu 24.8 to disable console idle
timeout.
c. To backup the configurations, use TFTP client program to get file 'rom-
0' from the Prestige.
d. To restore the configurations, use the TFTP client program to put your
configuration in file ROM-0 in the ZyAIR G-5100.
9. How do I backup/restore configurations by using FTP client program
via LAN?
a. Use the TELNET client program in your PC to login to your ZyAIR G-
5100.
b. To backup the configurations, use FTPclient program to get file 'rom-0'
from the Prestige.
c. To restore the configurations, use the FTP client program to put your
configuration in file ROM-0 in the ZyAIR G-5100.

Product FAQ
General FAQ
1. What is the ZyAIR G-5100 Wireless Access Point?
2. Which Applications can I use with the ZyAIR G-5100 ?
3. What is the coverage range of ZyAIR G-5100?
4. What is the range coverage of B-100/B-200/B-300/B-400?
5. What can I do if I lost the password for my ZyAIR G-5100 and can't
access it's configuration any more?
6. How do I used the reset button, more over what field of parameter will
be reset by reset button?
7. Why can't I configure B-100/B-200/B-300 with the supplied utility in
Windows XP
8. What is the default user name and password to login the ZyAIR G-5100
via the browser?
9. How can I manage the ZyAIR G-5100 ?
10. What network interface does the ZyAIR G-5100 support?
11. What is the maximum number of wireless client can associated with
ZyAIR G-5100 simultaneously?
Advanced FAQ
1. What is the default antenna type and gain on ZyAIR G-5100?
2. Can I change the antenna on ZyAIR G-5100?
3. What are the connector type required on the replacement antenna?
4. What is the RF power output of ZyAIR G-5100?
5. What wireless security mechanism are supported by ZyAIR G-5100?
6. What is the difference between Open System and Shared Key of
Authentication Type?
7. What authentication type does ZyAIR G-5100 support?

8. Why is the supplied utility for B-100/B-200/B-300 keep on prompting
"Invalid WEP key length" when I try to save my WEP configuration and
I am sure the configuration is correct?
9. I have problem associated with ZyAIR G-5100 with Symol wireless
PcMCIA card when WEP is enabled, why?
10. What are 802.1x authentication type and which authentication type does
ZyAIR G-5100 802.1x embeded server support.
11. How does the ZyAIR G-5100 support TFTP and FTP?
12. Which 802.1x authentication software client can ZyAIR G-5100 work
with?
1. What is the ZyAIR G-5100 Wireless Access Point?
The ZyAIR G-5100 is a outdoor wireless access point solution complete with
everything needed for providing high speed wireless capability to your existing
wired network. The ZyAIR G-5100 is equipped with one auto-MDI/MDIX
Ethernet LAN port and two 802.11g Wireless LAN interfaces. It is the simplest
and affordable solution for adding wireless mobile capability to your existing
wired Ethernet network. The ZyAIR G-5100 is equipped with PoE (Power over
Ethernet). This feature allows increased flexibility in the locating for your
ZyAIR G-5100.
Virtually all-popular applications over Internet, such as Web, E-Mail, FTP,
Telnet, Gopher, are supported. The ZyAIR G-5100 is designed for SOHO,
branch offices, workgroups, and educational users.
2. Which Applications can I use with the ZyAIR G-5100 ?
ZyAIR G-5100 is bridge between wired and wireless network, since bridge is a
layer 2 device it can carry all the upper layer protocol in other words it is
transparent to all applications.
You can use ZyAIR G-5100 to add wireless capability to your existing wired
network. Due to ZyAIR G-5100 is an outdoor access point, it is suitable to be

deployed in campus, business building, village, rail stations, etc. ZyAIR G-
5100 can be used in Browse the World Wide Web (WWW), send and receive
individual e-mail, and download software where you can do task you can do
with wired network generally can also be done on wireless network via ZyAIR
G-5100 wireless access point.
3. What is the coverage range of ZyAIR G-5100?
The coverage range typically is 500m~1000m outdoor. The actual range may
very depends on environment, as to obstacles and walls, RF interference, etc
in the environment.
4. What is the range coverage of B-100/B-101/B-200/B-220/B-300/B-400/G-
100 client adapter?
The coverage range typically is 50m~80m indoor, 150m~300m outdoor. The
actual range may very depends on environment, as to obstacles and walls, RF
interference, etc in the environment.
5. What can I do if I lost the password for my ZyAIR G-5100 and can't
access it's configuration any more?
If you have lost the password there is no way to gain access to the device
except to reset the device by pressing the reset button located by the power jack.
6. How do I used the reset button? More over what field of parameter will
be reset by reset button?
You can used a sharp pointed object insert it into the little reset hole beside the
power connector.
The procedures to reset the unit is as follow
1. Used a sharp pointed object insert it into the little reset hole beside the
power connector.
2. Press down the reset button and hold down for approx 10 second, the
unit will be reset .

Note: When the reset button is pressed all parameters will be reset back to
factory default including ESSID, password, IP address, WEP Keys.
The basic default configuration after reset is as follow.
1. IP address default: 192.168.1.2
2. Password default: 1234
3. ESSID default: Wireless
4. WEP:disabled
7. Why can't I configure B-100/B-101/B-200/B-220/B-300/B-400/G-100
client adapter with the supplied utility in Windows XP?
This is because XP uses it’s default configuration for wireless adapter. You can
disable it by entering Control Panel->Network and Dialup Connections-
>Wireless network connection->Advance and uncheck the use Windows to
configure wireless configuration check box and click OK. Now you need to
exit the supplied configuration utility in the Windows task bar and restart it
again. Now you can use the supplied utility to configure your B-100.
8. What is the default user name and password to login the ZyAIR G-5100
via the browser?
To restrict only the adminstrator can configure the router, there is a login
procedure prompted for asking User Name and Password. The default User
Name is 'admin' and the default password is the default SMT password,
'1234'.
9. How can I manage the ZyAIR G-5100 ?
■Configuration via web browser to the embedded Web Configurator.
■Telnet remote management
■TFTP (Trivial File Transfer Protocol), FTP firmware upgrade and
configuration backup and restore.
10. What network interface does the ZyAIR G-5100 support?

The ZyAIR G-5100 supports 1 auto MDX/MDIX 10/100M Ethernet interface
to connect to your existing wired Ethernet network and 1 802.11g wireless
interface to connect to the wireless stations in the coverage range..
11. What is the maximum number of wireless client can associated with
ZyAIR G-5100 simultaneously?
We did not limit the number of wireless client can associated with ZyAIR G-
5100 simultaneously, the suggest number are no more than 32, a good number
is under 10 to ensure the performance of each wireless client.
Advanced FAQ
1. What is the default antenna type and gain on ZyAIR G-5100?
The ZyAIR G-5100 are equip with omni directional antenna with 2 dBi Gains.
2. Can I change the antenna on ZyAIR G-5100?
Yes, you can change the antenna on ZyAIR G-5100 to fit your implementation
needs. To change antenna you must remove it first. You can remove the
antenna by holding the outer ring of the antenna and turn it counter clock wise,
and firmly remove the antenna from the ZyAIR G-5100. To install it simply
reverse the removing procedure.
3. What are the connector type required on the replacement antenna?
ZyAIR G-5100 are equip with Reverse Polarity SMA jack, so it will work with
any 2.4Ghz wireless antenna with Reverse Polarity SMA Plug.
4. What is the RF power output of ZyAIR G-5100?
The output power of ZyAIR G-5100 is 12dBm or 16mW from the RF module.

5. What wireless security mechanism are supported by ZyAIR G-5100?
ZyAIR G-5100 supports below security mechanisms.
1. MAC address filtering.
2. 64bit/128bit WEP (Wired Equivalent Privacy).
3. 802.1x/WPA authentication support.
6. What is the difference between Open System and Shared Key of
Authentication Type?
Open System:
The default authentication service that simply announces the desire to associate
with another station or access point. A station can authenticate with any other
station or access point using open system authentication if the receiving station
designates open system authentication.
Share Key:
The optional authentication that involves a more rigorous exchange of frames,
ensuring that the requesting station is authentic. For a station to use shared key
authentication, it must implement WEP.
7. What authentication type does ZyAIR G-5100 support?
ZyAIR G-5100 support null authentication when WEP is disabled as specified
by IEEE 802.11b/802.11g standard, and when WEP is enabled it is using
shared key authentication and data are encrypted at the same time.
8. Why is the supplied utility for B-100/B-101/B-200/B-220/B-300/G-100
keep on prompting "Invalid WEP key length" when I try to save my
WEP configuration and I am sure the configuration is correct?
Please make sure all 4 set of keys are with correct and WEP key length are also
correct. Do not leave any key field blank.
Note: Please make sure all 4 set of keys are consistent with the 4 set of keys
configured in AP.

9. I have problem associated with ZyAIR G-5100 with Symbol wireless
PCMCIA card when WEP is enabled, why?
This is because when WEP is enabled in ZyAIR G-5100 it is authenticating
using Shared key authentication. Symbol PcMCIA client do not support Shared
key Authentication. When configuring WEP encryption please ensure open
system is selected for authentication method. If you have several wireless NIC
card in your network and all are from different vendor please configure the
authentication method to 'Auto'. The system will auto detect the authentication
method of the station.
10. What are 802.1x authentication type and which authentication type
does ZyAIR G-5100 802.1x embedded server support.
802.1x specify the following authentication type, and the ZyAIR G-5100's
embedded 802.1x server only support MD5/CHAP authentication.
1. MD5/CHAP
2. One time password
3. Generic Token Card
4. TLS
5. TTLS
6. LEAP
7. PEAP
11. How does the ZyAIR G-5100 support TFTP and FTP?
In addition to the direct console port connection, the Prestige supports the
uploading/download of the firmware and configuration file using TFTP
(Trivial File Transfer Protocol) or FTP over LAN.
12. Which 802.1x authentication software client can ZyAIR G-5100 work
with?
ZyAIR G-5100 can work with the below test 802.1x authentication software.
For embedded MD5/CHAP authentication server

1. Windows XP embedded 802.1x client (Before SP1 patch).
2. Meetinghouse AEGIS client.
3. Funk Software Odyssey client.
For external TLS authentication server (Odyssey server).
1. Windows XP embedded 802.1x client
2. Funk Software Odyssey client
For external TTLS authentication server (Odyssey server)
1. Funk Software Odyssey client.
Note: 1. XP only support MD5/CHAP and TLS before SP1 patch, after upgrade
SP1, XP support only PEAT authentication.
2. When using external server ZyAIR G-5100 only act as a pass-through
thus no extra setting are required.

Wireless FAQ
General FAQ
1. What is a Wireless LAN ?
2. What are the main advantages of Wireless LANs ?
3. What are the disadvantages of Wireless LANs ?
4. Where can you find wireless 802.11 networks ?
5. What is an Access Point ?
6. What is IEEE 802.11 ?
7. What is IEEE 802.11b ?
8. How fast is 802.11b ?
9. What is IEEE 802.11a ?
10. What is IEEE 802.11g ?
11. Is it possible to use products from a variety of vendors ?
12. What is Wi-Fi ?
13. What types of devices use the 2.4GHz Band ?
14. Does Bluetooth interfer with wireless 802.11 LAN ?
15. Can radio signals pass through walls ?
16. What are potential factors that may cause interference among WLAN
products ?
17. What's the difference between a WLAN and a WWAN ?
Advanced FAQ
1. What is Ad Hoc mode ?
2. What is Infrastructure mode ?
3. How many Access Points are required in a given area ?
4. What is Direct-Sequence Spread Spectrum Technology – (DSSS) ?

5. What is Frequency-hopping Spread Spectrum Technology – (FHSS) ?
6. Do I need the same kind of antenna on both sides of a link ?
7. Why the 2.4 Ghz Frequency range ?
8. What is Server Set ID (SSID) ?
9. What is an ESSID ?
Security FAQ
1. How do I secure the data across an Access Point's radio link?
2. What is WEP ?
3. What is the difference between 40-bit and 64-bit WEP ?
4. What is a WEP key ?
5. Will 128-bit WEP communicate with 64-bit WEP ?
6. Can the SSID be encrypted ?
7. By turning off the broadcast of SSID, can someone still sniff the SSID ?
8. What are Insertion Attacks?
9. What is Wireless Sniffer ?
10. What is the difference between Open System and Shared Key of
Authentication Type ?
11. What is 802.1x ?
12. What is the difference between force-authorized, force-unauthorized and
auto?
13. What is AAA ?
14. What is RADIUS ?
Basic FAQ
1. What is a Wireless LAN ?
Wireless LANs provide all the functionality of wired LANs, without the need
for physical connections (wires). Data is modulated onto a radio frequency
carrier and transmitted through the ether. Typical bit-rates are 11Mbps and

54Mbps, although in practice data throughput is half of this. Wireless LANs
can be formed simply by equipping PC's with wireless NICs. If connectivity to
a wired LAN is required an Access Point (AP) is used as a bridging device.
AP's are typically located close to the centre of the wireless client population.
2. What are the advantages of Wireless LANs ?
a. Mobility:
Wireless LAN systems can provide LAN users with access to real-time
information anywhere in their organization. This mobility supports productivity
and service opportunities not possible with wired networks.
b. Installation Speed and Simplicity:
Installing a wireless LAN system can be fast and easy and can eliminate the
need to pull cable through walls and ceilings.
c. Installation Flexibility:
Wireless technology allows the network to go where wire cannot go.
d. Reduced Cost-of-Ownership:
While the initial investment required for wireless LAN hardware can be higher
than the cost of wired LAN hardware, overall installation expenses and life-
cycle costs can be significantly lower. Long-term cost benefits are greatest in
dynamic environments requiring frequent moves and changes.
e. Scalability:
Wireless LAN systems can be configured in a variety of topologies to meet the
needs of specific applications and installations. Configurations are easily
changed and range from peer-to-peer networks suitable for a small number of
users to full infrastructure networks of thousands of users that enable roaming
over a broad area.
3. What are the disadvantages of Wireless LANs ?
The speed of Wireless LAN is still relative slower than wired LAN. The most
popular wired LAN is operated in 100Mbps, which is almost 10 times of that of
Wireless LAN (10Mbps). A faster wired LAN standard (1000Mbps), which is
100 times faster, becomes popular as well. The setup cost of Wireless LAN is
relative high because the equipment cost including access point and PCMCIA

Wireless LAN card is higher than hubs and CAT 5 cables.
4. Where can you find wireless 802.11 networks ?
Airports, hotels, and even coffee shops like Starbucks are deploying 802.11
networks so people can wirelessly browse the Internet with their laptops. As
these types of networks increase, this will create additional security risk for the
remote user if not properly protected.
5. What is an Access Point ?
The AP (access point also known as a base station) is the wireless server that
with an antenna and a wired Ethernet connection that broadcasts information
using radio signals. AP typically act as a bridge for the clients. It can pass
information to wireless LAN cards that have been installed in computers or
laptops allowing those computers to connect to the campus network and the
Internet without wires.
6. What is IEEE 802.11 ?
The IEEE 802.11 is a wireless LAN industry standard, and the objective of
IEEE 802.11 is to make sure that different manufactures' wireless LAN devices
can communicate to each other.802.11 provides 1 or 2 Mbps transmission in
the 2.4 GHz ISM band using either FHSS or DSSS.
7. What is 802.11b ?
802.11b is the first revision of 802.11 standard allowing data rates up to
11Mbps in the 2.4GHz ISM band. Also known as 802.11 High-Rate and Wi-Fi.
802.11b only uses DSSS, the maximum speed of 11Mbps has fallbacks to 5.5,
2 and 1Mbps.
8. How fast is 802.11b ?
The IEEE 802.11b standard has a nominal speed of 11 megabits per second
(Mbps). However, depending on signal quality and how many other people are
using the wireless ethernet through a particular Access Point, usable speed will
be much less (on the order of 4 or 5 Mbps, which is still substantially faster
than most dialup, cable and DSL modems).
9. What is 802.11a ?
802.11a the second revision of 802.11 that operates in the unlicensed 5 GHz

band and allows transmission rates of up to 54Mbps. 802.11a uses OFDM
(orthogonal frequency division multiplexing) as opposed to FHSS or DSSS.
Higher data rates are possible by combining channels. Due to higher frequency,
range is less than lower frequency systems (i.e., 802.11b and 802.11g) and can
increase the cost of the overall solution because a greater number of access
points may be required. 802.11a is not directly compatible with 802.11b or
802.11g networks. In other words, a user equipped with an 802.11b or 802.11g
radio card will not be able to interface directly to an 802.11a access point.
Multi-mode NICs will solve this problem.
10. What is 802.11g ?
802.11g is an extension to 802.11b. 802.11g increases 802.11b's data rates to
54 Mbps and still utilize the the 2.4 GHz ISM. Modulation is based upon
OFDM (orthogonal frequency division multiplexing) technology. An 802.11b
radio card will interface directly with an 802.11g access point (and vice versa)
at 11 Mbps or lower depending on range. The range at 54 Mbps is less than for
802.11b operating at 11 Mbps.
11. Is it possible to use products from a variety of vendors ?
Yes. As long as the products comply to the same IEEE 802.11 standard. The
Wi-Fi logo is used to define 802.11b compatible products. Wi-Fi5 is a
compatibility standard for 802.11a products running in the 5GHz band.
12. What is Wi-Fi ?
The Wi-Fi logo signifies that a product is interoperable with wireless
networking equipment from other vendors. A Wi-Fi logo product has been
tested and certified by the Wireless Ethernet Compatibility Alliance (WECA).
The Socket Wireless LAN Card is Wi-Fi certified, and that means that it will
work (interoperate) with any brand of Access Point that is also Wi-Fi certified.
13. What types of devices use the 2.4GHz Band ?
Various spread spectrum radio communication applications use the 2.4 GHz
band. This includes WLAN systems (not necessarily of the type IEEE
802.11b), cordless phones, wireless medical telemetry equipment and
Bluetooth™ short-range wireless applications, which include connecting
printers to computers and connecting modems or hands-free kits to mobile
phones.

14. Does the 802.11 interfere with Bluetooth devices ?
Any time devices are operated in the same frequency band, there is the
potential for interference.
Both the 802.11b and Bluetooth devices occupy the same2.4-to-2.483-GHz
unlicensed frequency range-the same band. But a Bluetooth device would not
interfere with other 802.11 devices much more than another 802.11 device
would interefere. While more collisions are possible with the introduction of a
Bluetooth device, they are also possible with the introduction of another 802.11
device, or a new 2.4 GHz cordless phone for that matter. But, BlueTooth
devices are usually low-power, so the effects that a Bluetooth device may have
on an 802.11 network, if any, aren't far-reaching.
15. Can radio signals pass through walls ?
Transmitting through a wall is possible depending upon the material used in its
construction. In general, metals and substances with a high water content do
not allow radio waves to pass through. Metals reflect radio waves and concrete
attenuates radio waves. The amount of attenuation suffered in passing through
concrete will be a function of its thickness and amount of metal re-enforcement
used.
16. What are potential factors that may causes interference among WLAN
products ?
Factors of interference:
1. Obstacles: walls, ceilings, furniture… etc.
2. Building Materials: metal door, aluminum studs.
3. Electrical devices: microwaves, monitors, electric motors.
Solution :
1.Minimizing the number of walls and ceilings
2.Antenna is positioned for best reception
3.Keep WLAN products away from electrical devices, eg: microwaves,
monitors, electric motors,…, etc.
4. Add additional APs if necessary.
17. What's the difference between a WLAN and a WWAN ?
WLANs are generally privately owned, wireless systems that are deployed in a
corporation, warehouse, hospital, or educational campus setting. Data rates are
high and there are no per-packet charges for data transmission.
WWANs are generally publicly shared data networks designed to provide

coverage in metropolitan areas and along traffic corridors. WWANs are owned
by a service provider or carrier. Data rates are low and charges are based on
usage. Specialized applications are characteristically designed around short,
burst messaging.
Advanced FAQ
1. What is Ad Hoc mode ?
A wireless network consists of a number of stations without access points.
Without using an access point or any connection to a wired network.
2. What is Infrastructure mode ?
Infrastructure mode implies connectivity to a wired communications
infrastructure. If such connectivity is required the Access Points must be used
to connected to the wired LAN backbone. Wireless clients have their
configurations set for "infrastructure mode" in order to utilize access points
relaying.
3. How many Access Points are required in a given area ?
This depends on the surrounding terrain, the diameter of the client population,
and the number of clients. If an area is large with dispersed pockets of
populations then extension points can be used for extend coverage.
4. What is Direct-Sequence Spread Spectrum Technology – (DSSS) ?
DSSS spreads its signal continuously over a wide frequency band. DSSS maps
the information bearing bit-pattern at the sending station into a higher data rate
bit sequence using a "chipping" code. The chipping code (also known as
processing gain) introduces redundancy which allows data recovery if certain
bit errors occur during transmission. The FCC rules the minimum processing
gain should be 10, typical systems use processing gains of 20. IEEE 802.11b
specifies the use of DSSS.
5. What is Frequency-hopping Spread Spectrum Technology – (FHSS) ?
FHSS uses a narrowband carrier which hops through a predefined sequence of
several frequencies at a specific rate. This avoids problems with fixed channel