The beaconing table

Settings in the beaconing table influence the transmission of beacons by the access point in AP mode. In part this can influence the roaming behavior of clients, and in part this serves to optimize the MultiSSID mode for older WLAN clients.

LANconfig: Wireless LAN > General > Extended settings > Expert WLAN settings > Beaconing

Command line: Setup > Interfaces > WLAN > Beaconing

Beacon period

This value defines the time interval in Kµs between beacon transmission (1 Kµs corresponds to 1024 microseconds and is a measurement unit of the 802.11 standard. 1 Kµs is also known as a Timer Unit (TU)). Smaller values result in a shorter beacon timeout period for the client and enable quicker roaming in case of failure of an AP, but they also increase the WLAN overhead.

DTIM period

This value defines the number of beacons which are collected before multicasts are broadcast. Higher values enable longer client sleep intervals, but worsen the latency times.

Beacon order

Beacon order refers to the order in which beacons are sent to the various WLAN networks. For example, if three logical WLAN networks are active and the beacon period is 100 Kµs, then the beacons will be sent to the three WLANs every 100 Kµs. Depending on the beacon order, the beacons are transmitted at times as follows.

Cyclic

In this mode the AP transmits the first beacon transmission at 0 Kµs to WLAN-1, followed by WLAN-2 and WLAN-3. For the second beacon transmission (100 Kµs) WLAN-2 is the first recipient, followed by WLAN-3 and then WLAN-1. For the third beacon transmission (200 Kµs) the order is WLAN-3, WLAN-1, WLAN-2. After this the sequence starts again.

Staggered

In this mode, the beacons are not sent together at a particular time, rather they are divided across the available beacon periods. Beginning at 0 Kµs, WLAN-1 only is sent; after 33.3 Kµs WLAN-2, after 66.6 Kµs WLAN-3. At the start of a new beacon period, transmission starts again with WLAN-1.

Simple burst

In this mode the AP always transmits the beacons for the WLAN networks in the same order. The first beacon transmission (0 Kµs) is WLAN-1, WLAN-2 and WLAN-3; the second transmission is in the same order, and so on.

Some older WLANs are unable to process the quick succession of beacons which occur with simple burst. Consequently these clients often recognize the first beacons only and can only associate with this network. Staggered transmission of beacons produces better results but increases load on the AP's processor. The preset cyclic transmission proves to be a good compromise as all networks are transmitted first in turn.