Magiclan Overview - Samsung MagicLAN SWL-2300N User Manual

• Roaming
Roaming is a service that allows wireless clients to use the network in motion by automatically
changing the connection from an old Access Point to a new Access Point when the clients enter in
a new cell. During roaming the clients may observe the loose connection or delay in accessing the
resources of the network.
• Scanning, Beaconing & ESS ID
When a wireless client is initialized, it is necessary for it to find and communicate with the correct
group of wireless devices, including AP. At this point, it may search for all the frequency channels
and this process is called scanning.
There may be multiple APs and networks operating at the same time. It may be necessary to
ensure that the station joins with the correct network during the scanning process. To achieve this,
each AP is assigned to be part of a logical group called the Extended Service Set (ESS). The
name of this logical group is the ESS ID. When roaming is operating, there may be several Access
Points as part of the same ESS.
After the power on, wireless clients will listen on its default frequency channel. It will be listening
for beacons sent by another wireless station or AP. Beacon is a short message containing the ESS
ID that will be broadcast roughly ten times a second. When the wireless station hears a beacon
and the ESS ID in the beacon matches its own, the client knows that it is on the correct channel
and can communicate with its group. If no beacons are seen, or if the ESS ID does not match, the
wireless client may move to the next frequency channel and repeat this listening procedure.
In case of direct sequence spread spectrum (DSSS) physical layer, this scanning process occurs
at start up and may also occur when the client roams between APs.

1.3 MagicLAN Overview

• The MagicLAN
SWL-2300M/N/P e wireless LAN adapter
(MiniPCI/PCMCIA/PCI Card) ar
cards that provide wireless connection between computers.
• The MagicLAN is designed to operate with IEEE 802.11 (wireless LAN International
Standard) wireless compliant radio cards and uses a CSMA/CA (Collision Sense Multiple
Access with Collision Avoidance) algorithm as the media access scheme, which makes high speed
communication (with minimal collision probability) possible.
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