Lancom Systems LCOS 3.50 - Manual (Page 256)

LANCOM Reference Manual LCOS 3.50 ̈ Chapter 11: Wireless LAN – WLAN
256
Wi
re
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ss
L
A
N
–
WL
A
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IPSec over WLAN
Only with the
LANCOM VPN
Option. Not
available with all
LANCOM devices. With the help of the IPSec-over-WLAN technology in addition to the security
measures described already, a wireless network for the exchange of especially
sensitive data can be optimally secured. To this end, the LANCOM Wireless
access point is upgraded to a VPN gateway with the LANCOM VPN Option. In
addition to the encryption per 802.11i, WPA or WEP, the LANCOM Wireless
now offers the possibility of encrypting wireless connections with an IPSec-
based VPN.
11.5 Establishing outdoor wireless networks
LANCOM access points in combination with appropriate external antennae
are ideally suited to establishing point-to-point wireless connections to other
access points.
There are two main questions to be answered when setting up the wireless
connection:
̈ How should the antennae be positioned to ensure a problem-free
connection?
̈ What performance characteristics do the antennae need to ensure
sufficient data rates within legal limitations?
11.5.1 Geometrical layout of the transmission path
Antennae do not emit their signals linearly, but within an angle that depends
on the model in question. The spherical expansion of the signal waves is
characterised by constructive and destructive interference between these
waves at certain distances perpendicular to the line of sight between