1、 Device version: USG5120 V100R005C00SPC300
2、 WIFI card version: SU11APWN
3、 Symptom: it displays 144M when test with terminal test software after WIFI card plugged into, but it displays 300M when test TP-LINK wireless device at the same location.
If WIFI card is 300M in 802.111n, then the value after channel bandwidth should be 40.
1、 confirm whether SU11APWN supports 300M or not, the answer is yes.
2、 Confirm whether USG device and TP-LINK are at the same location or not, eliminating the factor of distance, the answer is yes.
3、 Confirm whether WIFI card configured correct or not, “radio-type dot11gn” configured correct, but there is a “channel bandwidth 20” configured in WIFI card interface.
USG will negotiate the value of channel bandwidth automatically, decided by the optimal performance that WIFI card supports, suggest not to modify it.