[timg11]

I noticed the default setting for "Preamble" under Wireless Settings / WL0-Advanced is Long.

In the history of 802.11 there have been a couple types of preambles. In the days of 802.11b, there was a short and long preamble option for the DSSS waveform that had to do with 802.11b backward compatibility with legacy 802.11 devices.

Then with 802.11n, the High Throughput (Greenfield) mode was defined with a shorter HT format preamble, but the longer legacy preamble was still available for use in mixed G/N networks.

I thought the "Preamble" under Wireless Settings / WL0-Advanced would select the 11n HT preamble, since 11b modes are rarely used anymore. However, I also expected that the preamble would follow the setting of Wireless Network Mode: If "NG Mixed" is set, default to long preamble. If "N Only" is set, default to short (HT) preamble.
After trying both modes, the default preamble remains set to Long.

Can anyone explain what the Preamble setting is controlling, and how it relates to the N / G / Mixed modes?

[tatsuya46]

iirc 802.11b devices can optionally support short preamble, 802.11g devices must support short preamble, so if u dont have 802.11b devices short preamble only is fine

[timg11]

tatsuya46, so you are saying that the Preamble setting in WL0-Advanced is for controlling the 802.11b DSSS/CCK waveform's short preamble selection, not the 802.11n HT (Greenfield) short preamble?


In that case the setting doesn't matter, assuming the network mode is set to N/G Mixed, which doesn't allow 802.11b devices to associate.