50

Appendix A: Troubleshooting

Frequently Asked Questions

Wireless-G Broadband Router with RangeBooster

What is the IEEE 802.11b standard?

It is one of the IEEE standards for wireless networks. The 802.11b standard allows wireless networking hardware

from different manufacturers to communicate, provided that the hardware complies with the 802.11b standard.

The 802.11b standard states a maximum data transfer rate of 11Mbps and an operating frequency of 2.4GHz.

What IEEE 802.11g features are supported?

The product supports the following IEEE 802.11g functions:

•

CSMA/CA plus Acknowledge protocol

•

OFDM protocol

•

Multi-Channel Roaming

•

Automatic Rate Selection

•

RTS/CTS feature

•

Fragmentation

•

Power Management

What IEEE 802.11b features are supported?

The product supports the following IEEE 802.11b functions:

•

CSMA/CA plus Acknowledge protocol

•

Multi-Channel Roaming

•

Automatic Rate Selection

•

RTS/CTS feature

•

Fragmentation

•

Power Management

What is ad-hoc mode?

When a wireless network is set to ad-hoc mode, the wireless-equipped computers are configured to

communicate directly with each other. The ad-hoc wireless network will not communicate with any wired

network.

What is infrastructure mode?

When a wireless network is set to infrastructure mode, the wireless network is configured to communicate with

a wired network through a wireless access point.

What is roaming?

Roaming is the ability of a portable computer user to communicate continuously while moving freely throughout

an area greater than that covered by a single access point. Before using the roaming function, the workstation

must make sure that it is the same channel number with the access point of dedicated coverage area.

To achieve true seamless connectivity, the wireless LAN must incorporate a number of different functions. Each

node and access point, for example, must always acknowledge receipt of each message. Each node must

51

Appendix A: Troubleshooting

Frequently Asked Questions

Wireless-G Broadband Router with RangeBooster

maintain contact with the wireless network even when not actually transmitting data. Achieving these functions

simultaneously requires a dynamic RF networking technology that links access points and nodes. In such a

system, the user’s end node undertakes a search for the best possible access to the system. First, it evaluates

such factors as signal strength and quality, as well as the message load currently being carried by each access

point and the distance of each access point to the wired backbone. Based on that information, the node next

selects the right access point and registers its address. Communications between end node and host computer

can then be transmitted up and down the backbone.

As the user moves on, the end node’s RF transmitter regularly checks the system to determine whether it is in

touch with the original access point or whether it should seek a new one. When a node no longer receives

acknowledgment from its original access point, it undertakes a new search. Upon finding a new access point, it

then re-registers, and the communication process continues.

What is ISM band?

The FCC and their counterparts outside of the U.S. have set aside bandwidth for unlicensed use in the ISM

(Industrial, Scientific and Medical) band. Spectrum in the vicinity of 2.4 GHz, in particular, is being made available

worldwide. This presents a truly revolutionary opportunity to place convenient high-speed wireless capabilities in

the hands of users around the globe.

What is Spread Spectrum?

Spread Spectrum technology is a wideband radio frequency technique developed by the military for use in

reliable, secure, mission-critical communications 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).

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, 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.

52

Appendix A: Troubleshooting

Frequently Asked Questions

Wireless-G Broadband Router with RangeBooster

What is WEP?

WEP is Wired Equivalent Privacy, a data privacy mechanism based on a 64-bit or 128-bit shared key algorithm, as

described in the IEEE 802.11 standard.

What is a MAC Address?

The Media Access Control (MAC) address is a unique number assigned by the manufacturer to any Ethernet

networking device, such as a network adapter, that allows the network to identify it at the hardware level. For all

practical purposes, this number is usually permanent. Unlike IP addresses, which can change every time a

computer logs onto the network, the MAC address of a device stays the same, making it a valuable identifier for

the network.

How do I reset the Router?

Press the Reset button on the back panel for about five seconds. This will reset the Router to its default settings.

How do I resolve issues with signal loss?

There is no way to know the exact range of your wireless network without testing. Every obstacle placed between

the Router and a wireless PC will create signal loss.

Lead glass, metal, concrete floors, water and walls will

inhibit the signal and reduce range.

Start with the Router and your wireless PC in the same room and move it

away in small increments to determine the maximum range in your environment.

You may also try using different channels, as this may eliminate interference affecting only one channel.

I have excellent signal strength, but I cannot see my network.

Wireless security is probably enabled on the Router, but not on your wireless adapter (or vice versa).

Verify that

the same wireless security method and passphrase/keys are being used on all devices of your wireless network.

How many channels/frequencies are available with the Router?

There are eleven available channels, ranging from 1 to 11, in North America. There may be additional channels

available in other regions, subject to the regulations of your region and/or country.

If your questions are not addressed here, refer to the Linksys website, www.linksys.com.

53

Appendix B: Wireless Security

Security Precautions

Wireless-G Broadband Router with RangeBooster

Appendix B: Wireless Security

Linksys wants to make wireless networking as safe and easy for you as possible. The current generation of

Linksys products provide several network security features, but they require specific action on your part for

implementation. So, keep the following in mind whenever you are setting up or using your wireless network.

Security Precautions

The following is a complete list of security precautions to take (at least steps 1 through 5 should be followed):

1.

Change the default SSID.

2.

Disable SSID Broadcast.

3.

Change the default password for the Administrator account.

4.

Enable MAC Address Filtering.

5.

Change the SSID periodically.

6.

Use the highest encryption algorithm possible. Use WPA if it is available. Please note that this may reduce

your network performance.

7.

Change the WEP encryption keys periodically.

For information on implementing these security features, refer to “Chapter 6: Configuring the Wireless-G

Broadband Router with RangeBooster.”

Security Threats Facing Wireless Networks

Wireless networks are easy to find. Hackers know that in order to join a wireless network, wireless networking

products first listen for “beacon messages”. These messages can be easily decrypted and contain much of the

network’s information, such as the network’s SSID (Service Set Identifier). Here are the steps you can take:

Change the administrator’s password regularly.

With every wireless networking device you use, keep in

mind that network settings (SSID, WEP keys, etc.) are stored in its firmware. Your network administrator is the

only person who can change network settings. If a hacker gets a hold of the administrator’s password, he, too,

can change those settings. So, make it harder for a hacker to get that information. Change the administrator’s

password regularly.

NOTE:

Some of these security features are

available only through the network router or

access point. Refer to the router or access

point’s documentation for more information.

54

Appendix B: Wireless Security

Security Threats Facing Wireless Networks

Wireless-G Broadband Router with RangeBooster

SSID.

There are several things to keep in mind about the SSID:

1.

Disable Broadcast

2.

Make it unique

3.

Change it often

Most wireless networking devices will give you the option of broadcasting the SSID. While this option may be

more convenient, it allows anyone to log into your wireless network. This includes hackers. So, don’t broadcast

the SSID.

Wireless networking products come with a default SSID set by the factory. (The Linksys default SSID is “linksys”.)

Hackers know these defaults and can check these against your network. Change your SSID to something unique

and not something related to your company or the networking products you use.

Change your SSID regularly so that any hackers who have gained access to your wireless network will have to

start from the beginning in trying to break in.

MAC Addresses.

Enable MAC Address filtering. MAC Address filtering will allow you to provide access to only

those wireless nodes with certain MAC Addresses. This makes it harder for a hacker to access your network with

a random MAC Address.

WEP Encryption.

Wired Equivalent Privacy (WEP) is often looked upon as a cure-all for wireless security

concerns. This is overstating WEP’s ability. Again, this can only provide enough security to make a hacker’s job

more difficult.

There are several ways that WEP can be maximized:

1.

Use the highest level of encryption possible

2.

Use “Shared Key” authentication

3.

Change your WEP key regularly

WPA.

Wi-Fi Protected Access (WPA) is the newest and best available standard in Wi-Fi security. Two modes are

available: WPA Personal and WPA Enterprise. WPA Personal gives you a choice of two encryption methods: TKIP

(Temporal Key Integrity Protocol), which utilizes a stronger encryption method and incorporates Message

Integrity Code (MIC) to provide protection against hackers, and AES (Advanced Encryption System), which utilizes

a symmetric 128-Bit block data encryption. WPA Enterprise uses TKIP or AES encryption and utilizes a RADIUS

(Remote Authentication Dial-In User Service) server for authentication.

IMPORTANT:

Always remember that each

device in your wireless network MUST use

the same encryption method and encryption

key or your wireless network will not function

properly.