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What are Ad-hoc and Infrastructure modes?
An Ad-hoc wireless LAN is a group of computers, each with a WLAN adapter,
connected as an independent wireless LAN. An Ad-hoc wireless LAN is applicable when
no AP is available or you wish to run a private network not joined to the corporate
wireless network.
Because the NB5580W can only operate in Access Point mode when you wish to
connect to it your Wireless client adapters (connected to your computers) MUST be set
to Infrastructure mode.
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 as the Access Point of the 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 ESSID?
An Infrastructure configuration can support roaming for mobile workers. More than one
Access point can be configured as an with the same SSID. Users within range of atleast
one Access point could roam freely between Access points while maintaining a
continuous connection to the wireless network.
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.
www.netcomm.com.au
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Rev.1 - YML686
NP5580/W User Guide
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