LANCOM WLC
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4006 - LANCOM WLC
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4025
Chapter 1: Introduction
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EN
The Access Point sends a "discovery request message" at the beginning of
communication to determine the available WLAN Controllers. This request is
sent as a broadcast. However, because in some structures a potential WLAN
Controller cannot be reached by a broadcast, special addresses from addi-
tional WLAN Controllers can also be entered into the configuration of the
Access Points.
DNS names of WLAN Controllers can also be resolved. All Access
Points with LCOS 7.22 or higher have the default name 'WLC-Address'
pre-configured so that a DNS server can resolve this name to a
LANCOM WLAN Controller. This also makes it possible to reach WLAN
Controllers that are not located in the same network, without having
to configure the Access Points.
From the available WLAN Controllers, the Access Point selects the best one
and queries it for the structure of the DTLS connection. For the Access Point,
the "best" WLAN Controller is the one with the least load, i.e., the lowest ratio
of managedAccess Points compared to the maximum possible Access Points.
In case of two or more equally "good" WLAN Controllers, the Access Point
selects the nearest one in the network, i.e., the one with the fastest response
time.
The WLAN Controller then uses an internal random number to determine a
unique and secure session key which it uses to protect the connection to the
Access Point. The WLAN Controller also automatically creates a self-signed
certificate for the Access Point with which it can later uniquely identify itself
to the WLAN Controller.
The Access Point is provided with the configuration for the integrated SCEP
client via the secure DTLS connection – the Access Point is then able to retrieve
its certificate from the SCEP CA via SCEP. Once this is done, the assigned con-
figuration is transferred to the Access Point.
SCEP stands for Simple Certificate Encryption Protocol; CA for Certifi-
cation Authority. Refer to the LCOS reference manual for further infor-
mation about digital certificates, CAs and SCEP.