Westermo RM-80 - Manual (Page 16)

16 6193-4201
Chapter Three OPERATION
3.1 Start-up
“Access Point” Start-up
An Access Point unit starts and immediately begins transmitting periodic messages called
beacons. These beacon messages are messages contain information for Clients on how to
establish a link with the Access Point.
Any Client that hears the messages, which are not already linked to another Access Point
unit, will respond and links will be established between the new Access Point and these
Clients.
“Client” Start-up
When a Client powers up, it immediately scans for messages from Access Point units. The
Client will continue to scan for twice the configured beacon interval in the Client. During
the scan, the RX led will flicker now and again indicating messages received, perhaps from
an Access Point. If the Client finds suitable Access Points during the scan, it will then
attempt to establish a link with the Access Point with the strongest radio signal.
Link Establishment
When the Client wishes to establish a link with an Access Point it follows a two step
process. The first step is “authentication”. During this step the Client and Access Point
check if they can establish a secure link, based upon the configured security encryption.
Once the Client has been authenticated, it will then request a link. This step is called
“association”.
While no links have been established, the LINK led will be OFF. Once a single link has
been established, the LINK led is ON.
After the link is established, data may be transferred in both directions. The Access Point
will act as a master-unit and will control the flow of information to the Clients linked to
it.
The maximum number of 255 Clients may be linked to an Access Point.