Ieee 802.11R; Requirements For Installation And Operation - Siemens SCALANCE W1780 Configuration Manual

The SCALANCE W devices support both types of frame aggregation. You make the settings on
the WBM page "AP 802.11n/ac (Page 237)".
Maximum ratio combining (MRC)
In a multiple antenna system, the wireless signals are received by the individual antennas and
combined to form one signal. The MRC method is used to combine the wireless signals. The
MRC method weights the wireless signals according to their signal-to-noise ratio and combines
the wireless signals to form one signal. The signal-to-noise ratio is improved and the error rate
is reduced.
2.5

IEEE 802.11r

During roaming, the WLAN client roams from one access point to the next. A delay time of
several 100 ms can come about at the connection transition.
The following steps can be executed during this time:
● Client searches for a new access point (scanning)
● Logon at a new access point (authentication and association)
● Allow a data connection via the new access point
Shorter delay times are required for time-critical applications, for example, Voice over IP. The
standard IEEE 802.11r contains amendments which optimize roaming and therefore is also
referred to as Fast BSS Transition (FT).
With FT, the WLAN client must not authenticate every time the access point changes. For this
purpose, the access points are grouped into a mobility domain. The WLAN client receives the
mobility domain ID from the first access point to which it logs on. The log-on information is
buffered within the mobility domain. This logon is valid for all members of the mobility domain.
Based on the ID, the WLAN client recognizes whether the access point is a member of the
same mobility domain and can therefore log on without delay. Only WLAN clients with IEEE
802.11r support can use the improved roaming or handover functions.
Requirement
● The access points are members of the same mobility domain
● Only possible with WPA2 encryption (WPA2-PSK and WPA2 RADIUS)
2.6

Requirements for installation and operation

A PG/PC with network connection must be available in order to configure the SCALANCE W
devices. If no DHCP server is available, a PC on which the Primary Setup Tool (PST) is
installed is necessary for the initial assignment of an IP address to the SCALANCE W devices.
For the other configuration settings, a computer with Telnet or a Web browser is necessary.
SCALANCE W1780/W1740 according to IEEE 802.11ac Web Based Management
Configuration Manual, 11/2019, C79000-G8976-C485-03
2.6 Requirements for installation and operation
Description
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