kmod-usb-net-rndis: Unstable USB-tethering connection in v23.05.5, 24.10.rc5 and 24.10.0

openwrt-23.05.5-ath79-generic-dlink_dir-835-a1-squashfs-sysupgrade


"system": "Atheros AR9344 rev 1",
"model": "D-LINK DIR-835 A1",
"board_name": "dlink,dir-835-a1",
"rootfs_type": "squashfs",

Hi,

While USB-tethering does work for me in v23.05, the connection becomes unstable/unusable after a couple of hours of use: ping times increase to ~1s instead of ~50ms I usually get, many dropped packets and sometimes I see something like the following:

# ping 1.1.1.1
PING 1.1.1.1 (1.1.1.1) 56(84) bytes of data.
64 bytes from 1.1.1.1: icmp_seq=1 ttl=52 time=632 ms
64 bytes from 1.1.1.1: icmp_seq=2 ttl=52 time=472 ms
64 bytes from 1.1.1.1: icmp_seq=3 ttl=52 time=199 ms
64 bytes from 1.1.1.1: icmp_seq=4 ttl=52 time=50.8 ms
64 bytes from 1.1.1.1: icmp_seq=5 ttl=52 time=100 ms
64 bytes from 1.1.1.1: icmp_seq=6 ttl=52 time=197 ms
wrong data byte #54 should be 0x36 but was 0x76
#16     10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
#48     30 31 32 33 34 35 76 cb
64 bytes from 1.1.1.1: icmp_seq=8 ttl=52 time=139 ms
wrong data byte #54 should be 0x36 but was 0x30
#16     10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
...
^C
--- 1.1.1.1 ping statistics ---
16 packets transmitted, 13 received, 18.75% packet loss, time 15037ms
rtt min/avg/max/mdev = 50.796/274.266/682.831/215.647 ms

Installing kmod-usb-net-cdc-ncm doesn't seem to improve stability. Installing kmod-usb-net-cdc-eem in addition to kmod-usb-net-cdc-ncm also doesn't seem to improve stability.

The following is what I did to get USB-tething working with v23.05.02

# opkg update
# opkg install kmod-usb-net-rndis
# opkg install kmod-usb-core kmod-usb-ehci kmod-usb2

# opkg list-installed | grep usb
kmod-phy-ath79-usb - 5.15.167-1
kmod-usb-core - 5.15.167-1
kmod-usb-ehci - 5.15.167-1
kmod-usb-net - 5.15.167-1
kmod-usb-net-cdc-ether - 5.15.167-1
kmod-usb-net-rndis - 5.15.167-1
kmod-usb2 - 5.15.167-1

Any ideas? Thanks

Start with the reported kmod-usb-net-rndis setup, the D-LINK DIR-835 A1 hardware details, and the ping output showing latency, packet loss, and corrupted data. Reproduce the instability over several hours across the listed OpenWrt versions and USB networking modules; done means identifying a confirmed cause and a validated fix or workaround.