Linksys WPC54GX manual What is roaming?

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Wireless-G Notebook Adapter with SRX

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 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

Appendix A: Troubleshooting

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Frequently Asked Questions

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Contents Wireless- G Copyright and Trademarks Table of Contents Front Panel List of Figures22 Radius EAP-TLS Introduction WelcomeWhat’s in this Guide? Introduction What’s in this Guide? Planning Your Wireless Network Network TopologyRoaming Network Layout LED Indicators Getting to Know the Wireless-G Notebook Adapter with SRXSetting up the Wireless-G Notebook Adapter with SRX Running the Setup WizardOverview Setup Wizard’s Ssid Wireless Network Name Screen WEP Setup Wizard’s Check Settings Screen Setup Wizard’s Congratulations Screen Using the Wireless Network Monitor Accessing the Wireless Network MonitorLink Information Wireless Network Status Wireless Network Statistics Site Information Site SurveyProfile Information ProfilesEnter Profile Name Creating a New Profile10 Wireless Mode for New Profile 12 Wireless Security WEP for New Profile 14 Wireless Security WPA-Personal 16 Wireless Security WPA-Enterprise EAP-TLS EAP-PEAP 22 Radius EAP-TLS 24 Radius EAP-PEAP 26 Congratulations Appendix a Troubleshooting Common Problems and SolutionsFrequently Asked Questions What is the Ieee 802.11b standard? What is roaming? What is WEP? Appendix B Wireless Security Security PrecautionsSecurity Threats Facing Wireless Networks Appendix B Wireless Security Wireless-G Notebook Adapter with SRX TCP/IP Appendix C Windows HelpAppendix D Glossary Wireless-G Notebook Adapter with SRX Wireless-G Notebook Adapter with SRX Wireless-G Notebook Adapter with SRX Wireless-G Notebook Adapter with SRX Wireless-G Notebook Adapter with SRX Wireless-G Notebook Adapter with SRX WPC54GX Appendix E SpecificationsLimited Warranty Appendix F Warranty InformationFCC Statement Appendix G Regulatory InformationSafety Notices Appendix H Contact Information
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