2023-04-13 21:52:34

by Ben Greear

[permalink] [raw]
Subject: mtk7922 in 160Mhz AP mode not working properly.

Hello,

I did some testing with mtk7922 radios in AP mode today, on 6E band.

STA is an mtk7921 radio, and sniffer is also 7921.

In 80Mhz mode, it seems to work fine, but when I tell AP to go to 160
Mhz mode, then it seems that AP cannot transmit data frame (properly) to STA.
mtk7921 STA associates but will not get DHCP. Sniffing ap interface shows DHCP Discover
and attempt to send DHCP response.

Sniffer shows lots of RTS/CTS when AP should be sending DHCP response, but sniffer
cannot decode any frames. Possibly AP is transmitting at 160Mhz, even though STA
should not be advertising that it can do such since 7921 is 80Mhz max.

An intel ax210 STA radio doesn't even show scan results when AP is in 160 Mode,
but connects right away when AP is in 80Mhz mode.

From what I can tell, the AP's beacon is also missing the sections that indicate it
can do 160Mhz. I assume that should not keep it from sending data frames properly.
And always possible I am screwing up the hostapd config, which is below.

interface=vap922
driver=nl80211
logger_syslog=-1
logger_syslog_level=2
logger_stdout=-1
logger_stdout_level=2
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=vap-mtk7922
bssid=3c:55:76:6d:ae:4f
country_code=US
ieee80211d=1
ieee80211h=1
ieee80211w=2
hw_mode=a
beacon_int=100
dtim_period=2
max_num_sta=2007
rts_threshold=2347
preamble=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
# Enable HT modes if you want 300Mbps+ throughput.
#ht_capab=[HT20][HT40-][HT40+][GF][SHORT-GI-20][SHORT-GI-40]
# [TX-STBC][RX-STBC123][MAX-AMSDU-7935][DSSS_CCK-40][PSMP][LSIG-TXOP-PROT]
#ht_capab=[HT20][HT40+][HT40-][SHORT-GI-40][SHORT-GI-20][LDPC][TX-SDBC][RX-STBC1][DSSS_CCK-40]
#vht_capab=[MAX-MPDU-11454][RXLDPC][SHORT-GI-80][TX-STBC-2BY1][RX-STBC-1][MAX-A-MPDU-LEN-EXP0][RX-ANTENNA-PATTERN][TX-ANTENNA-PATTERN][SU-BEAMFORMER][SU-BEAMFORMEE][MU-BEAMFORMER][VHT160-80PLUS80][MAX-A-MPDU-LEN-EXP7][BF-ANTENNA-2][SOUNDING-DIMENSION-2][BF-ANTENNA-3][SOUNDING-DIMENSION-3]

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
op_class=134

ieee80211ax=1
he_default_pe_duration=4
he_rts_threshold=1023
he_oper_chwidth=2

channel=33
he_oper_centr_freq_seg0_idx=47
supported_rates=60 90 120 180 240 360 480 540
ieee8021x=0
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1
wpa_pairwise=TKIP CCMP
rsn_pairwise=CCMP
sae_pwe=2
wpa_passphrase=lanforge
wpa=2
wpa_key_mgmt=SAE


Thanks,
Ben



--
Ben Greear <[email protected]>
Candela Technologies Inc http://www.candelatech.com


2023-04-13 22:15:14

by Ben Greear

[permalink] [raw]
Subject: Re: mtk7922 in 160Mhz AP mode not working properly.

On 4/13/23 14:47, Ben Greear wrote:
> Hello,
>
> I did some testing with mtk7922 radios in AP mode today, on 6E band.

Err, I finally looked at the right piece of info after sending this.
7922 iw phy info indicates only 80Mhz supported in AP mode, but 160Mhz
in STA mode. That would explain why I see strange issues I guess.

Thanks,
Ben

>
> STA is an mtk7921 radio, and sniffer is also 7921.
>
> In 80Mhz mode, it seems to work fine, but when I tell AP to go to 160
> Mhz mode, then it seems that AP cannot transmit data frame (properly) to STA.
> mtk7921 STA associates but will not get DHCP.  Sniffing ap interface shows DHCP Discover
> and attempt to send DHCP response.
>
> Sniffer shows lots of RTS/CTS when AP should be sending DHCP response, but sniffer
> cannot decode any frames.  Possibly AP is transmitting at 160Mhz, even though STA
> should not be advertising that it can do such since 7921 is 80Mhz max.
>
> An intel ax210 STA radio doesn't even show scan results when AP is in 160 Mode,
> but connects right away when AP is in 80Mhz mode.
>
> From what I can tell, the AP's beacon is also missing the sections that indicate it
> can do 160Mhz.  I assume that should not keep it from sending data frames properly.
> And always possible I am screwing up the hostapd config, which is below.
>
> interface=vap922
> driver=nl80211
> logger_syslog=-1
> logger_syslog_level=2
> logger_stdout=-1
> logger_stdout_level=2
> ctrl_interface=/var/run/hostapd
> ctrl_interface_group=0
> ssid=vap-mtk7922
> bssid=3c:55:76:6d:ae:4f
> country_code=US
> ieee80211d=1
> ieee80211h=1
> ieee80211w=2
> hw_mode=a
> beacon_int=100
> dtim_period=2
> max_num_sta=2007
> rts_threshold=2347
> preamble=0
> macaddr_acl=0
> auth_algs=1
> ignore_broadcast_ssid=0
> # Enable HT modes if you want 300Mbps+ throughput.
> #ht_capab=[HT20][HT40-][HT40+][GF][SHORT-GI-20][SHORT-GI-40]
> #         [TX-STBC][RX-STBC123][MAX-AMSDU-7935][DSSS_CCK-40][PSMP][LSIG-TXOP-PROT]
> #ht_capab=[HT20][HT40+][HT40-][SHORT-GI-40][SHORT-GI-20][LDPC][TX-SDBC][RX-STBC1][DSSS_CCK-40]
> #vht_capab=[MAX-MPDU-11454][RXLDPC][SHORT-GI-80][TX-STBC-2BY1][RX-STBC-1][MAX-A-MPDU-LEN-EXP0][RX-ANTENNA-PATTERN][TX-ANTENNA-PATTERN][SU-BEAMFORMER][SU-BEAMFORMEE][MU-BEAMFORMER][VHT160-80PLUS80][MAX-A-MPDU-LEN-EXP7][BF-ANTENNA-2][SOUNDING-DIMENSION-2][BF-ANTENNA-3][SOUNDING-DIMENSION-3]
>
> 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
> op_class=134
>
> ieee80211ax=1
> he_default_pe_duration=4
> he_rts_threshold=1023
> he_oper_chwidth=2
>
> channel=33
> he_oper_centr_freq_seg0_idx=47
> supported_rates=60 90 120 180 240 360 480 540
> ieee8021x=0
> eapol_key_index_workaround=0
> eap_server=0
> own_ip_addr=127.0.0.1
> wpa_pairwise=TKIP CCMP
> rsn_pairwise=CCMP
> sae_pwe=2
> wpa_passphrase=lanforge
> wpa=2
> wpa_key_mgmt=SAE
>
>
> Thanks,
> Ben
>
>
>