Cisco WIRELESS-G WBP54G - Manual (Page 24)

19 Appendix A: Troubleshooting
Frequently Asked Questions
Wireless-G Bridge for Phone Adapters
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 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 to communicate continuously while the user is 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 the 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