Ytdyklly

Introduction:

In an effort to avoid purchasing extraneous hardware, I've managed to configure my media center PC as a wireless access point using hostapd in bridge mode.

This works, but I'm experiencing an issue where any traffic that originates from the media center itself destined for a wireless host is significantly slower than traffic that is sent in the opposite direction or that simply passes through it from upstream.

I tested using several different protocols (iperf3 TCP/UDP, scp, samba, netcat TCP/UDP...) and all exhibit the same behavior, leading me to believe that the bridge configuration is at fault (i.e. it's a layer 2 issue).

Test breakdown:

1) WiFi 1     --> BridgeBox: ~300 Mbit/s

2) BridgeBox  -->    WiFi 1: ~15 Mbit/s TCP, ~150 Mbit/s UDP

3) Internet   -->    WiFi 1: ~200 Mbit/s (limited by ISP)

4) Wired 1    -->    WiFi 1: ~300 Mbit/s

5) WiFi 1     -->   Wired 1: ~300 Mbit/s

Things I've tried:

• Changing the bridge HW address to random (was cloned from wireless interface). No change.


• Changing the bridge HW address to match wired NIC. No change.


• Plugging in a USB NIC and adding it to the bridge. For whatever reason, even if nothing is connected to this interface, this causes test 2 bandwidth to jump to ~50 Mbit/s.

Configuration:

BridgeBox:~$ uname -a



Linux BridgeBox 4.15.0-43-generic #46~16.04.1-Ubuntu SMP Fri Dec 7 13:31:08 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

BridgeBox:~$ cat /etc/network/interfaces



auto lo br0 wlp2s0



iface lo inet loopback



iface br0 inet static

  bridge_ports enp3s0

    address 192.168.12.2

    broadcast 192.168.12.255

    netmask 255.255.255.0

    gateway 192.168.12.1

    dns-nameserver 1.1.1.1

    dns-nameserver 8.8.8.8



iface wlp2s0 inet manual

    hostapd /etc/hostapd/hostapd.conf

BridgeBox $ cat /etc/hostapd/hostapd.conf



interface=wlp2s0

bridge=br0

driver=nl80211

logger_syslog=-1

logger_syslog_level=1

logger_stdout=-1

logger_stdout_level=2

ctrl_interface=/var/run/hostapd

ctrl_interface_group=0

beacon_int=100

dtim_period=2

max_num_sta=255

macaddr_acl=0

ignore_broadcast_ssid=0



### WMM

wmm_enabled=1

uapsd_advertisement_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



### TX queue parameters

tx_queue_data3_aifs=7

tx_queue_data3_cwmin=15

tx_queue_data3_cwmax=1023

tx_queue_data3_burst=0

tx_queue_data2_aifs=3

tx_queue_data2_cwmin=15

tx_queue_data2_cwmax=63

tx_queue_data2_burst=0

tx_queue_data1_aifs=1

tx_queue_data1_cwmin=7

tx_queue_data1_cwmax=15

tx_queue_data1_burst=3.0

tx_queue_data0_aifs=1

tx_queue_data0_cwmin=3

tx_queue_data0_cwmax=7

tx_queue_data0_burst=1.5



ieee80211n=1

ht_capab=[LDPC][TX-STBC][RX-STBC1][DSSS_CCK-40][HT40+][HT40-]

ieee80211ac=1

vht_capab=[MAX-MPDU-11454][RXLDPC][SHORT-GI-80][TX-STBC-2BY1][RX-STBC-2BY1][MAX-A-MPDU-LEN-EXP7][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



#SSID and WPA settings

ssid=<xxxxxxx>

country_code=IL

hw_mode=a

channel=36

wpa=2

auth_algs=1

wpa_passphrase=<xxxxxxxx>

wpa_pairwise=TKIP CCMP

BridgeBox:-$ sudo lshw -C network | grep product

       product: QCA6174 802.11ac Wireless Network Adapter

       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller

Suggestions would be much appreciated.