How to know which standard my Wi-Fi connection is currently using

My laptop has capabilities for 802.11n connections.

With my previous router, I could transer data faster than 54Mb/s. Now I have D-Link router and for some reason the maximum connection speed is 54Mb/s, which implies that the connection was established with 802.11g.

How can I check which standard (g or n) has been established? Is there any command to get that information? (nm-applet does not give any information about that in the connection information window).

The utility iw shows the used bitrate and indicates the used IEEE 802.11 standard by its listed capabilities.

Read your interface name from the iw dev output, and use it within <name>.

iw dev <name> link 

Example output when associated with a legacy (non-802.11n) AP:

    tx bitrate: 36.0 MBit/s

"MCS index", indicating a 802.11n AP:

    tx bitrate: 300.0 MBit/s MCS 15 40Mhz short GI

"VHT", indicating support for 802.11ac:

    tx bitrate: 86.7 MBit/s VHT-MCS 8 short GI VHT-NSS 1

Compare this with the linux driver 802.11n table. You'll see how the example "MCS 15 40Mhz short GI" 300 MBit/s corresponds to a row within the "HT40 rates" for the "short 400ns GI" column.

To see what your wifi adapter is general capable of, independent of the AP link, run iw phy0 info (synonymous to iw list) and look for keywords like HT (802.11n) / VHT (802.11ac, (Very) High Throughput), MCS (Modulation and Coding Schemes) index number and long/short GI (Guard Interval).

For more explanations, continue with this superuser answer.

1. try lshw -C network
2. try iwconfig and search for Bit Rate
3. try lspci | grep -i wireless
4. wavemon is the ultimate tool for wireless