D-Link Router User Manual page 54

Section 3 - Configuration
Control Choose the channel selection mode as Upper or Lower. The default
Sideband: setting is Upper.
Aggregation:
Check this box to enable frame aggregation. Frame aggregation
is a feature of 802.11n and 802.11ac that allows overhead to be
reduced by transmitting multiple frames simultaneous under the
same header. Disabling this feature will reduce throughput, but
may increase compatibility with legacy equipment or allow links
in poor network conditions. The default and recommended setting
is Enable.
Short GI:
Check this box to reduce the guard interval to 400 ns. This can
increase the throughput rate provided that the delay spread of the
connection is also low. However, it can also increase error rate in
some installations, due to increased sensitivity to radio-frequency
reflections. Select the option that works best for your installation.
Click Apply to save your settings, or Cancel to revert to your previous settings.
D-Link DWR-961 User Manual 49