Skyr@cer USB 4001g
Full User Guide
CONTENTS
1.1 Features......................................................................................................................... 2
1.2 Specifications................................................................................................................ 2
1.3 Package Contents.......................................................................................................... 3
3.1 Site Survey.................................................................................................................... 8
3.2 Profile............................................................................................................................ 9
3.2.1.1 Configuration ........................................................................................................ 10
3.2.1.2 Authentication and Security.................................................................................. 12
3.2.1.3 802.1x Setting-Certification.................................................................................. 16
3.2.1.4 802.1x Setting-CA Server ..................................................................................... 17
3.3 Link Status .................................................................................................................. 18
3.4 Statistics ...................................................................................................................... 20
3.5 Advance ...................................................................................................................... 20
1 Introduction
Thank you for purchasing the 802.11g Wireless LAN USB Adapter. This USB adapter is designed to
comply with IEEE 802.11g Wireless LAN standard and easy to carry with the Mini size. It is suitable for
any Laptop or Desktop computers.
This adaptor supports higher data throughput than the IEEE 802.11g standard (up to 54Mbps). It
supports specific ways to increase the data transfer rate at a time; compress the data and decrease the
waiting time to send the next data to the Routers or APs. This feature is called Turbo Mode. When the
adaptor is connecting to the Routers or APs with the proprietary feature, the wireless network will be
more effective.
For WLAN security issues, this adaptor supports 64/128-bit WEP data encryption that protects your
wireless network from eavesdropping. It also supports WPA (Wi-Fi Protected Access) feature that
combines IEEE 802.1x and TKIP (Temporal Key Integrity Protocol) technologies. Client users are
required to authorize before accessing to APs or AP Routers, and the data transmitted in the network is
encrypted/decrypted by a dynamically changed secret key. Furthermore, this adaptor supports WPA2
function, WPA2 provides a stronger encryption mechanism through AES (Advanced Encryption
Standard), which is a requirement for some corporate and government users.
This adapter is cost-effective, together with the versatile features; it is the best solution for you to build
your wireless network.
1
1.1 Features
•
•
•
Complies with the IEEE 802.11b and IEEE 802.11g 2.4GHz (DSSS) standards.
High data transfer rate – up to 54Mbps.
Supports Turbo Mode to enhance the data transfer speed within the specific wireless
network.
•
Supports 64/128-bit WEP, WPA (TKIP with IEEE 802.1x), WPA2 (AES with IEEE
802.1x) functions for high level of security.
•
•
•
Supports the most popular operating system: Windows 98SE/Me/2000/XP/2003 Server.
Supports USB 2.0/1.1/1.0 interface.
Portable and mini-size design.
1.2 Specifications
•
•
•
•
Standards: IEEE 802.11b/g
Bus Type: USB 2.0 Type A
Frequency Band: 2.4000 ~ 2.4835GHz (Industrial Scientific Medical Band)
Modulation: OFDM with BPSK, QPSK, 16QAM, 64QAM (11g)
BPSK, QPSK, CCK (11b)
•
•
Data Rate: 54/48/36/24/18/12/11/9/6/5.5/2/1Mbps auto fallback
Securities: 64/128-bit WEP Data Encryption, WPA (TKIP with IEEE 802.1x), WPA2
(AES with IEEE 802.1x)
Note: WPA2 is only enabled in Windows 2000/XP/2003 Server.
Antenna: Internal Antenna
•
•
•
•
•
•
•
•
•
Drivers: Windows 2000/XP/2003 Server
LEDs: Link/Activity
Transmit Power: 17dBm ± 2dBm
Receive Sensitivity: -70dBm@54Mbps, -83.5dBm@11Mbps
Dimension: 9(H) x 27(W) x 87(D) mm
Temperature: 32~122°F (0 ~ 50°C)
Humidity: 10-95% (NonCondensing)
Certification: FCC, CE
2
2 Installation Procedure
Before you proceed with the installation, please notice following descriptions.
Note1: Please do not install the adaptor into your computer before installing the software
program from the CD.
Note2: The following installation was operated under Windows XP. (Procedures are similar for
Windows 2000/2003 Server.)
Note3: If you have installed the Turbo Wireless LAN USB Adaptor driver & utility before, please
uninstall the old version first.
A. Insert the Installation CD to your CD-ROM Drive. Choose “Install Software”
B. Click “Yes” to process the installation if you accept the license agreement.
4
C. If you need the adaptor to operate with better performance, please choose the “Optimize for
performance” to enable the Tx Burst mode. Or you can choose “Optimize for Wi-Fi mode” to let the
adaptor run in standard wireless network.
5
D. The system starts to install the software of the adaptor. Please follow the instructions of the
program to plug in the adaptor into the USB port of your computer. And the system will
automatically detect the adaptor
E. Please click “Finish” to complete the installation.
6
3 Configuration Utility
The Topcom Configuration Utility is a powerful application that helps you configure the USB adaptor
and monitor the link status and the statistics during the communication process.
When the adaptor is installed, the configuration utility will be displayed automatically. This adaptor will
auto connect to wireless device which has better signal strength and no wireless security setting.
The Topcom Configuration Utility appears as an icon on the system tray of Windows while the adaptor
is running. You can open the utility by double-click on the icon.
In Windows XP, there is a “Windows Zero Configuration Tool” for you to setup wireless clients. If you
want to switch to use Topcom configuration utility, please follow one of the ways as below.
Right click the icon in the system tray and select “Use Topcom Wireless LAN Configuration utility”.
7
3.1
Site Survey
When you open the Topcom Configuration Utility, the system will scan all the channels to find all the
access points/stations within the accessible range of your adaptor and automatically connect to the
wireless device with the highest signal strength. From the “Site Survey”, all the networks nearby will be
listed. You can change the connection to another networks or add one of the networks to your own
profile list.
Parameter
Description
Available Networks
This list shows all available wireless networks within range of your
adaptor. It also displays the information of the networks including
the SSID, BSSID, Signal Strength, Channel, Encryption,
Authentication and Network Type. If you want to connect to any
networks on the list, double-click the item on the list, and the
adaptor will automatically connect to the selected network.
Rescan Button
Click “Rescan” button to collect the new information of all the
wireless networks nearby.
Connect Button
Click “Connect” to connect to the selected network.
Add the selected network to Profiles list.
Add to Profile Button
8
3.2
Profile
The “Profiles List” is for you to manage the networks you connect to frequently. You are able to
Add/Delete/Edit/Activate a profile.
Parameter
Description
Profiles List
The profiles list display all the profiles and the relative settings of
the profiles including Profile Name, SSID, Channel, etc.
This sign indicates the activated profile is been connecting.
This sign indicates the activated profile is not been
connecting.
Add/Delete/Edit Button
Activate Button
Click these buttons to add/delete/edit the selected profiles.
Click “Activate” to connect to the selected profile. When a profile is
activated, the adaptor will be initially connected to the profile.
9
3.2.1 Configure the Profile
3.2.1.1 Configuration
Parameter
Description
Profile Name
Define a recognizable profile name for you to identify the different
networks.
SSID
The SSID (up to 32 printable ASCII characters) is the unique
name identified in a WLAN. The ID prevents the unintentional
merging of two co-located WLANs.
You may specify a SSID for the adaptor and then only the device
with the same SSID can interconnect to the adaptor. If you want to
add the network nearby to the profile list, pull down the menu, all
the networks will be listed for you to add one of them to the profile
list.
10
Parameter
Description
PSM (Power Saving Mode)
The power saving function is only available when the network type
is in Infrastructure.
CAM (Constantly Awake Mode) – The adaptor will always set in
active mode.
PSM (Power Saving Mode) – Enable the adaptor in the power
saving mode when it is idle.
Network Type
Infrastructure – This operation mode requires the presence of an
802.11 Access Point. All communication is done via the Access
Point or Router.
Ad-Hoc – Select this mode if you want to connect to another
wireless stations in the Wireless LAN network without through an
Access Point or Router.
TX Power
If you want to lower the transmit power of the adaptor for saving the
power of the system, you can select the lower percentages from the
list. The lower power will cause the lower signal strength and the
coverage range.
Ad Hoc Wireless Mode
When the adaptor is set in Ad Hoc (Peer to Peer Mode), you can
designate the wireless connection mode for the Ad Hoc network.
802.11 B only – This adaptor can be compatible with both 802.11g
and 802.11b wireless stations. If there are only 802.11b wireless
stations in the network, you can set the adaptor to this mode.
802.11 B/G mix – If you have a mix of 802.11b and 802.11g
wireless stations in your network, it is recommended to set the
adaptor to this mode. This mode is also the default setting.
802.11 G only – This adaptor can be compatible with both 802.11g
and 802.11b wireless stations. If there are only 802.11g wireless
stations in the network, you can set the adaptor to this mode.
Preamble
The preamble defines the length of the CRC block for
communication among wireless devices. This option is only active
in the Ad Hoc network.
There are two modes including Auto and Long Preamble. If
“Auto“ mode is selected, the adaptor will auto switch the preamble
mode depending on the wireless devices the adaptor is connecting
to.
11
Parameter
Description
RTS Threshold
Minimum packet size required for an RTS (Request To Send). For
packets smaller than this threshold, an RTS is not sent and the
packet is transmitted directly to the wireless network. Select a
setting within a range of 0 to 2347 bytes. Minor change is
recommended.
Fragment Threshold
The value defines the maximum size of packets; any packet size
larger than the value will be fragmented. If you have decreased
this value and experience high packet error rates, you can
increase it again, but it will likely decrease overall network
performance. Select a setting within a range of 256 to 2346 bytes.
Minor change is recommended.
Channel
This setting is only available for Ad Hoc mode. Select the number
of the radio channel used for the networking. The channel setting
should be the same with the network you are connecting to.
3.2.1.2 Authentication and Security
Parameter
Description
Authentication Type
This setting has to be consistent with the wireless networks that
the adaptor intends to connect.
Open – No authentication is needed among the wireless network.
Shared – Only wireless devices using a shared key (WEP Key
identified) are allowed to connecting each other.
12
Parameter
Description
Authentication Type
LEAP – LEAP is a pre-EAP, Cisco-proprietary protocol, with many
of the features of EAP protocols. Cisco controls the ability of other
vendors to implement this protocol, so it should be selected for
use only when limited vendor choice for client, access-point, and
server products is not a concern. When you have set up LEAP
authentication, you have to enter the user name and password of
your computer.
WPA – WPA provides a scheme of mutual authentication using
either IEEE 802.1x/Extensible Authentication Protocol (EAP)
authentication or pre-shared key (PSK) technology. It provides a
high level of assurance to enterprises, small businesses and
home users that data will remain protected and that only
authorized users may access their networks. For enterprises that
have already deployed IEEE 802.1x authentication, WPA offers
the advantage of leveraging existing authentication databases
and infrastructure.
WPA-PSK – It is a special mode designed for home and small
business users who do not have access to network authentication
servers. In this mode, known as Pre-Shared Key, the user
manually enters the starting password in their access point or
gateway, as well as in each wireless stations in the network.
WPA-PSK takes over automatically from that point, keeping
unauthorized users that don't have the matching password from
joining the network, while encrypting the data traveling between
authorized devices.
WPA2 – Like WPA, WPA2 supports IEEE 802.1x/EAP
authentication or PSK technology. It also includes a new
advanced encryption mechanism using the Advanced Encryption
Standard (AES). AES is required to the corporate user or
government users. The difference between WPA and WPA2 is that
WPA2 provides data encryption via the AES. In contrast, WPA
uses Temporal Key Integrity Protocol (TKIP).
WPA2-PSK – WPA2-PSK is also for home and small business.
The difference between WPA-PSK and WPA2-PSK is that
WPA2-PSK provides data encryption via the AES. In contrast,
WPA-PSK uses Temporal Key Integrity Protocol (TKIP).
802.1x Setting
When you have set the Authentication Type to Open, Shared,
WPA or WPA2, you can also enable IEEE 802.1x setting to use
the authentication server or certification server to authenticate
client users.
13
Parameter
Description
Encryption Mode
None – Disable the encryption mode.
WEP – Enable the WEP Data Encryption. When the item is
selected, you have to continue setting the WEP Encryption keys.
TKIP – TKIP (Temporal Key Integrity Protocol) changes the
temporal key every 10,000 packets (a packet is a kind of message
transmitted over a network.) This ensures much greater security
than the standard WEP security.
AES – AES has been developed to ensure the highest degree of
security and authenticity for digital information and it is the most
advanced solution defined by IEEE 802.11i for the security in the
wireless network.
Note: All devices in the network should use the same encryption
method to ensure the communication.
WPA Pre-Shared Key
The WPA-PSK key can be from 8 to 64 characters and can be
letters or numbers. This same key must be used on all of the
wireless stations in the network.
WEP Key
The WEP keys are used to encrypt data transmitted in the
wireless network. There are two types of key length: 64-bit and
128-bit. Select the default encryption key from Key 1 to Key 4 by
selected the radio button.
(Key1 ~ Key4)
Fill the text box by following the rules below.
64-bit – Input 10-digit Hex values (in the “A-F”, “a-f” and “0-9”
range) or 5-digit ASCII characters (including “a-z” and “0-9”) as
the encryption keys. For example: “0123456aef“ or “test1”.
128-bit – Input 26-digit Hex values (in the “A-F”, “a-f” and “0-9”
range) or 13-digit ASCII characters (including “a-z” and “0-9”) as
the encryption keys. For example:
“01234567890123456789abcdef“ or “administrator”.
14
The IEEE 802.1X specification describes a protocol that can be used for authenticating both clients and
servers on a network. The authentication algorithms and methods are those provided by the Extensible
Authentication Protocol (EAP), a method of authentication that has been in use for a number of years
on networks that provide Point-to-Point Protocol (PPP) support as many internet service providers and
enterprises do.
When an AP acting as an authenticator detects a wireless station on the LAN, it sends an EAP-Request
for the user's identity to the device. (EAP, or the Extensible Authentication Protocol, is an authentication
protocol that runs before network layer protocols transmit data over the link.) In turn, the device
responds with its identity, and the AP relays this identity to an authentication server, which is typically
an external RADIUS server.
An example for MD5 Authentication
IEEE 802.1x
Access Client
RADIUS
Client
RADIUS
Server
3
1
Access Point
2
4
Windows 2000 IAS
(Internet Authentication
Service)
(1) Client requests to login the
network.
(3) Send username, password to
RADIUS server.
(4) Approve or deny user
login to the LAN.
15
3.2.1.3 802.1x Setting-Certification
Parameter
Description
Authentication Type
The EAP authentication protocols this adaptor has supported are
included as follows. This setting has to be consistent with the
wireless APs or Routers that the adaptor intends to connect.
PEAP &TTLS – PEAP and TTLS are similar and easier than TLS
in that they specify a stand-alone authentication protocol be used
within an encrypted tunnel. TTLS supports any protocol within its
tunnel, including CHAP, MS-CHAP, MS-CHAPv2, PAP and
EAP-MD5. PEAP specifies that an EAP-compliant authentication
protocol must be used; this adaptor supports EAP-MSCHAP v2,
EAP-TLS/Smart Card and Generic Token Card. The client
certificate is optional required for the authentication.
TLS/Smart Card –TLS is the most secure of the EAP protocols
but not easy to use. It requires that digital certificates be
exchanged in the authentication phase. The server presents a
certificate to the client. After validating the server’s certificate, the
client presents a client certificate to the server for validation.
MD5-Challenge – MD5-Challenge is the easiest EAP Type. It
requires the wireless station to enter a set of user name and
password as the identity to RADIUS Server.
Session Resumption
There are “Disabled”, “Reauthentication”, “Roaming”, “SameSsid”
and “Always” selections for you to choose whether to recovery the
session in different status.
Identity
Enter the name as the identity for the server.
Enter the password as the identity for the server.
Password
Use Client Certificate
A client certificate is required for TLS, and is optional for TTLS and
PEAP. This forces a client certificate to be selected from the
appropriate Windows Certificate Store and made available to the
RADIUS server for certification.
16
Parameter
Description
Tunneled Authentication
Protocol
When the authentication type is PEAP or TTLS, select a protocol
to be used to build the encrypted tunnel.
Identity
This is the protected user EAP Identity used for authentication.
The identity specified may contain up to 63 ASCII characters, is
case sensitive and takes the form of a Network Access Identifier,
consisting of <name of the user>@<user’s home realm>. The
user’s home realm is optional and indicates the routing domain.
Password
The password used for authentication. It may contain up to 63
ASCII characters and is case sensitive.
3.2.1.4 802.1x Setting-CA Server
Parameter
Description
Use Certificate Chain
When the EAP authentication type such as TLS, TTLS or PEAP is
selected and required a certification to tell the client what server
credentials to accept from the authentication server in order to
verify the server, you have to enable this function.
Certificate Issuer
Choose the server from the list to issue the certificate. If “Any
Trusted CA” is selected, any CA included in the list (provided by
the Microsoft Certificate Store) is permitted.
17
Parameter
Description
Allow Intermediate Certificates
A server designates an issuer as a trusted root authority by
placing the issuer's self-signed certificate, which contains the
issuer's public key, into the trusted root certification authority
certificate store of the host computer. Intermediate or subordinate
certification authorities are trusted only if they have a valid
certification path from a trusted root certification authority.
Server Name
Enter the authentication server name.
Server name must match exactly When selected, the server name must match exactly the server
name found on the certificate.
Domain name must end in
specified name
When selected, the server name field identifies a domain. The
certificate must use a server name belonging to this domain or to
one of its sub-domains (e.g. zeelans.com, where the server is
blueberry.zeelans.com) but it may be any name used in the
certificate name field.
3.3
Link Status
From the “Link Status” option, you can view all the information of the network you are connecting to.
18
Parameter
Status
Description
Display the SSID and MAC ID of the network the adaptor is
connecting to.
Extra Info
Channel
Display the link status.
Display the number of the radio channel and the frequency used
for the networking.
Link Speed (Mbps)
Display the transmission and reception rate of the network. The
maximum transmission rate is 54Mbps.
Throughput (Kbps)
Link Quality
Display the speed of data transmitted and received.
This bar indicates the quality of the link. The higher the
percentage, the better the quality.
dBm
If you want to know the signal strength in the unit of dBm, select
this check box.
Signal Strength
This bar shows the signal strength level. The higher percentage
shown in the bar, the more radio signal been received by the
adaptor. This indicator helps to find the proper position of the
wireless device for quality network operation.
Noise Level
Display the noise level in the wireless environment.
19
3.4
Statistics
This option enables you to view the statistic information of the connection including transmit statistics
and receive statistics. You may reset the counters by clicking ”Reset Counter”.
3.5
Advance
This option enables you to configure more advanced settings, for example: wireless mode, protection
mode and etc.
20
Parameter
Description
Wireless Mode
802.11 B/G mix – If you have a mix of 802.11b and 802.11g
wireless stations in your network, it is recommended to set the
adaptor to this mode. This mode is also the default setting.
802.11 B only – This adaptor can be compatible with both 802.11g
and 802.11b wireless stations. If there are only 802.11b wireless
stations in the network, you can set the adaptor to this mode.
802.11 G only – This adaptor can be compatible with both 802.11g
and 802.11b wireless stations. If there are only 802.11g wireless
stations in the network, you can set the adaptor to this mode.
Select Your Country Region Code The available channel differs from different countries. For example:
USA (FCC) is channel 1-11, Europe (ETSI) is channel 1-13. The
operating frequency channel will be restricted to the country user
located before importing. If you are in different country, you have to
adjust the channel setting to comply the regulation of the country.
B/G Protection
If you have a mix of 802.11b and 802.11g wireless stations in the
network, it is recommended to enable the protection mechanism.
This mechanism can decrease the rate of data collision between
802.11b and 802.11g wireless stations. When the protection mode
is enabled, the throughput of the adaptor will be a little lower due to
many of frame traffic should be transmitted.
Auto – Based on the status of the network and automatically
disable/enable protection mode.
On – Always enable the protection mode.
Off – Always disable the protection mode.
Tx Rate
There are several options including
Auto/1/2/5.5/11/6/9/12/18/24/36/48/54Mbps for you to select.
When the “Auto” is selected, the device will choose the most
suitable transmission rate automatically. The higher data rate you
designated in the network, the shorter distance is allowed between
the adaptor and the wireless stations.
When the wireless mode is “802.11 B only”, the maximum data rate
is 11Mbps (11b) so that there are only “Auto/1/2/5.5/11Mbps”
options you can select.
Tx BURST
Tx Burst enables the adaptor to deliver better throughput in the
same period and environment.
21
Parameter
Description
Enable TCP Window Size
The TCP Window is the amount of data a sender can send on a
particular connection before it gets an acknowledgment back from
the receiver that it has gotten some of it. When the Router or AP
the adaptor is connecting to have set up the TCP Window, you can
enable the parameter to meet the data size for the Router or AP
connection. The larger TCP Window the better performance.
Fast Roaming at -70dBm
When you want to fast roaming to the network nearby without
intercepting the wireless connection especially the adaptor is
applied to the multimedia application or a voice call, you can
enable the parameter. The adaptor will fast roaming to the near
network when the receive sensitivity (signal strength) is lower to
the value you have set up.
Turn Off RF Button
CCX 2.0
If you want to turn off the radio of the adaptor temporarily, click this
button. To turn on the radio, click this button again.
CCX 2.0 (Cisco Compatible Extensions) is developed by Cisco for
the radio monitoring and fast roaming.
LEAP Turn on CCKM
During normal operation, LEAP-enabled client devices mutually
authenticate with a new access point by performing a complete
LEAP authentication, including communication with the main
RADIUS server.
When you configure your wireless LAN for fast re-association,
however, LEAP-enabled client devices roam from one access
point to another without involving the main server. Using Cisco
Centralized Key Management (CCKM), an access point configured
to provide Wireless Domain Services (WDS) takes the place of the
RADIUS server and authenticates the client so quickly that there is
no perceptible delay in voice or other time-sensitive applications.
Enable Radio Measurement
When this parameter is enabled, the Cisco AP can run the radio
monitoring through the associated CCX-compliant clients to
continuously monitor the WLAN radio environment and discover
any new APs that are transmitting beacons.
Non-Serving Channel
Measurements
The Cisco AP can perform monitoring measurements through the
CCX-compliant clients on the non-serving channels when this
parameter is enabled.
It limits the channel measurement time. The default value is 250
milliseconds.
Limit xxx milliseconds (0-2000)
22
3.6
About
By choosing this option, you can click the hyperlink to connect the website for the information of the
wireless chipset vendor and review basic information about the Utility such as the Driver, Utility and
EEPROM Version. The MAC Address of the adaptor is displayed in the screen as well.
3.7
Turbo Mode
This adaptor supports specific ways to increase the data transfer rate at a time; compress the data and
decrease the waiting time to send the next data to the Routers or APs, this feature (known as Turbo
Mode) enables higher throughput than IEEE 802.11g standard (Up to 54Mbps).
When the adaptor is connecting to the Routers or APs with the proprietary Turbo Mode feature, the
Turbo Mode will be enabled automatically without any configuration.
23
24
4 Troubleshooting
This chapter provides solutions to problems usually encountered during the installation and operation
of the adapter.
1. What is the IEEE 802.11g standard?
802.11g is the new IEEE standard for high-speed wireless LAN communications that provides for
up to 54 Mbps data rate in the 2.4 GHz band. 802.11g is quickly becoming the next mainstream
wireless LAN technology for the home, office and public networks.
802.11g defines the use of the same OFDM modulation technique specified in IEEE 802.11a for
the 5 GHz frequency band and applies it in the same 2.4 GHz frequency band as IEEE 802.11b.
The 802.11g standard requires backward compatibility with 802.11b.
The standard specifically calls for:
A. A new physical layer for the 802.11 Medium Access Control (MAC) in the 2.4 GHz frequency
band, known as the extended rate PHY (ERP). The ERP adds OFDM as a mandatory new
coding scheme for 6, 12 and 24 Mbps (mandatory speeds), and 18, 36, 48 and 54 Mbps
(optional speeds). The ERP includes the modulation schemes found in 802.11b including
CCK for 11 and 5.5 Mbps and Barker code modulation for 2 and 1 Mbps.
B. A protection mechanism called RTS/CTS that governs how 802.11g devices and 802.11b
devices interoperate.
2. What is the IEEE 802.11b standard？
The IEEE 802.11b Wireless LAN standard subcommittee, which formulates the standard for the
industry. The objective is to enable wireless LAN hardware from different manufactures to
communicate.
3. What does IEEE 802.11 feature support？
The product supports the following IEEE 802.11 functions:
z
z
z
z
z
z
CSMA/CA plus Acknowledge Protocol
Multi-Channel Roaming
Automatic Rate Selection
RTS/CTS Feature
Fragmentation
Power Management
4. What is Ad-hoc？
An Ad-hoc integrated wireless LAN is a group of computers, each has a Wireless LAN adapter,
Connected as an independent wireless LAN. Ad hoc wireless LAN is applicable at a
departmental scale for a branch or SOHO operation.
5. What is Infrastructure？
An integrated wireless and wireless and wired LAN is called an Infrastructure configuration.
Infrastructure is applicable to enterprise scale for wireless access to central database, or
wireless application for mobile workers.
25
6. What is BSS ID？
A specific Ad hoc LAN is called a Basic Service Set (BSS). Computers in a BSS must be
configured with the same BSS ID.
7. What is WEP？
WEP is Wired Equivalent Privacy, a data privacy mechanism based on a 40 bit shared key
algorithm, as described in the IEEE 802 .11 standard.
8. What is TKIP?
TKIP is a quick-fix method to quickly overcome the inherent weaknesses in WEP security,
especially the reuse of encryption keys. TKIP is involved in the IEEE 802.11i WLAN security
standard, and the specification might be officially released by early 2003.
9. What is AES?
AES (Advanced Encryption Standard), a chip-based security, has been developed to ensure the
highest degree of security and authenticity for digital information, wherever and however
communicated or stored, while making more efficient use of hardware and/or software than
previous encryption standards. It is also included in IEEE 802.11i standard. Compare with AES,
TKIP is a temporary protocol for replacing WEP security until manufacturers implement AES at
the hardware level.
10. Can Wireless products support printer sharing？
Wireless products perform the same function as LAN products. Therefore, Wireless products can
work with Netware, Windows 2000, or other LAN operating systems to support printer or file
sharing.
11. Would the information be intercepted while transmitting on air？
WLAN features two-fold protection in security. On the hardware side, as with Direct Sequence
Spread Spectrum technology, it has the inherent security feature of scrambling. On the software
side, WLAN series offer the encryption function (WEP) to enhance security and Access Control.
Users can set it up depending upon their needs.
12. What is DSSS？What is FHSS？And what are their differences？
Frequency-hopping spread-spectrum (FHSS) uses a narrowband carrier that changes frequency
in a pattern that is known to both transmitter and receiver. Properly synchronized, the net effect
is to maintain a single logical channel. To an unintended receiver, FHSS appears to be
short-duration impulse noise. Direct-sequence spread-spectrum (DSSS) generates a redundant
bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The
longer the chip is, the greater the probability that the original data can be recovered. Even if one
or more bits in the chip are damaged during transmission, statistical techniques embedded in the
radio can recover the original data without-the need for retransmission. To an unintended
receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most
narrowband receivers.
26
13. What is Spread Spectrum？
Spread Spectrum technology is a wideband radio frequency technique developed by the military
for use in reliable, secure, mission-critical communication systems. It is designed to trade off
bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is
consumed than in the case of narrowband transmission, but the trade off produces a signal that
is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of
the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a
spread –spectrum signal looks like background noise. There are two main alternatives, Direct
Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).
27
|