ASUS USB-AC51 mt7610u AP: client station download speed is consistently 2x less than upload?

[lkraav]

After a lot of learnings with hostapd and how HT/VHT works, I think I'm near maxing out this small dongle as a bridged AP.

But wifi client download speed remains a bit of a mystery. This is my laptop with AX203 👇

⌁53% [leho:~]└2 $ nmcli device wifi 
IN-USE  BSSID              SSID          MODE   CHAN  RATE        SIGNAL  BARS  SECURITY  
*       04:42:1A:5B:AC:CF  s62-xt-1nac   Infra  36    135 Mbit/s  62      ▂▄▆_  WPA2 WPA3 

⌁44% [leho:~]└2 $ speedtest
Retrieving speedtest.net configuration...
Testing from Telia Eesti (x.y.z.w)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Telia Eesti AS (Tallinn) [1.28 km]: 2.984 ms
Testing download speed................................................................................
Download: 113.56 Mbit/s
Testing upload speed......................................................................................................
Upload: 240.01 Mbit/s

hostapd.conf is stock, with adapter-specific overrides

θ69° [root@gusto:hostapd] ± grep ^# -v hostapd.conf | grep -v ^$
interface=wlp8s0f4u1
bridge=bridge0
driver=nl80211
logger_syslog=-1
logger_syslog_level=1
logger_stdout=-1
logger_stdout_level=2
ssid=s62-xt-1nac
country_code=EE
ieee80211d=1
ieee80211h=1
hw_mode=a
channel=36
beacon_int=100
dtim_period=2
max_num_sta=255
rts_threshold=-1
fragm_threshold=-1
macaddr_acl=0
auth_algs=3
ignore_broadcast_ssid=0
wmm_enabled=1
wmm_ac_bk_cwmin=4
wmm_ac_bk_cwmax=10
wmm_ac_bk_aifs=7
wmm_ac_bk_txop_limit=0
wmm_ac_bk_acm=0
wmm_ac_be_aifs=3
wmm_ac_be_cwmin=4
wmm_ac_be_cwmax=10
wmm_ac_be_txop_limit=0
wmm_ac_be_acm=0
wmm_ac_vi_aifs=2
wmm_ac_vi_cwmin=3
wmm_ac_vi_cwmax=4
wmm_ac_vi_txop_limit=94
wmm_ac_vi_acm=0
wmm_ac_vo_aifs=2
wmm_ac_vo_cwmin=2
wmm_ac_vo_cwmax=3
wmm_ac_vo_txop_limit=47
wmm_ac_vo_acm=0
disassoc_low_ack=1
ieee80211n=1
ht_capab=[HT40+][HT40-][GF][SHORT-GI-20][SHORT-GI-40][RX-STBC1]
ieee80211ac=1
vht_capab=[SHORT-GI-80][RX-STBC1][MAX-A-MPDU-LEN-EXP3][RX-ANTENNA-PATTERN][TX-ANTENNA-PATTERN]
vht_oper_chwidth=1
vht_oper_centr_freq_seg0_idx=42
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1
wpa=2
wpa_passphrase=<hidden>
wpa_key_mgmt=WPA-PSK WPA-PSK-SHA256 SAE
wpa_pairwise=CCMP CCMP-256
ieee80211w=1
sae_require_mfp=1

#31 seems similar problem, but I already have hostapd.conf upgraded to that level.

Any thoughts on what I'm missing?

[morrownr]

Hi @lkraav

I'd be interested to know what signal level and link quality you would see with wavemon when running your tests. Can you install and run wavemon?

Upload: 240.01 Mbit/s

I don't believe this number. The mt7610u chipset can do a link rate of up to 433 Mbps. Since this is half duplex technology and this is a 1st generation WiFi 5 chipset, cut that number in half and you can expect the upload / download to max out at around 216 give or take some of the magic stuff that wifi does. I usually see that chipset max out at around 210 Mbps in clean air (no congestion, using a clean DFS channel). The rtl8811cu can get up to around 270 Mbps but it is what I will call a 2nd generation WiFi 5 chipset that can show faster numbers based on new technologies if the router supports them. Generally Mediatek's 1st generation WiFi 5 chipsets are about 10-15 % slower than the Realtek 2nd generation WiFi 5 chipsets. Interestingly enough, when we skip forward to present day WiFi 6 class adapters, the Mediatek mt7921au chipset shows to be about 10-15 % faster than the Realtek rtl8832bu so it appears that Mediatek has flipped the performance picture with the latest generation.

Download: 113.56 Mbit/s

This is a number I can believe. Remember that wifi is designed to be a sharing technology so you are sharing the bandwidth with any other APs/clients that are on the same channel which will mean reduced numbers. You can only get the max numbers if there are no other APs/clients on your channel... such as you can get on a clean DFS channel. Since I don't know what the congestion level is at your location, I can't say if the adapter is at max performance but on channel 36, in most countries, the congestion can be heavy depending on where you live. That number is good and should handle several things.

@morrownr