<!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> After creating a usbmon trace and letting ChatGPT-5 analyze it: Short answer: your pings stopped working because you told the modem to expect QMAP frames, but the host is still sending plain raw‑IP on <code data-start="143" data-end="150">wwan0</code>. With WDA set to <code data-start="170" data-end="206">ul-protocol=qmap, dl-protocol=qmap</code>, the device will drop raw‑IP uplink packets as “incorrectly received”, which matches the counter you’re seeing. On Linux, adding the 4‑byte QMAP header on TX (and stripping it on RX) only happens if you either: <ul data-start="419" data-end="567"> <li data-start="419" data-end="495"> create a <code data-start="432" data-end="440">qmimux</code> interface (kernel’s built‑in QMAP multiplexer), or </li> <li data-start="496" data-end="567"> put the device into pass‑through and let <code data-start="545" data-end="552">rmnet</code> handle QMAP. </li> </ul> If you enable QMAP in the modem but keep using <code data-start="616" data-end="623">wwan0</code> directly without <code data-start="641" data-end="649">qmimux</code>/<code data-start="650" data-end="657">rmnet</code>, uplink traffic won’t be accepted. <div class="moz-cite-prefix">Am 18.08.2025 um 08:35 schrieb Martin Maurer: </div> <blockquote type="cite" cite="mid:115b3805-a16e-4e65-94ec-c424404a69c5@mmeacs.de">Here is an additional note: I was missing ip route replace default dev wwan0 but this does not make it going. I tried: root@test-phyboard-pollux-imx8mp-3:~# qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-get-packet-statistics [/dev/cdc-wdm0] Connection statistics: TX packets OK: 1 RX packets OK: 2 TX packets dropped: 0 RX packets dropped: 0 TX bytes OK: 79 RX bytes OK: 223 root@test-phyboard-pollux-imx8mp-3:~# ping -4 -I wwan0 8.8.8.8 PING 8.8.8.8 (8.8.8.8): 56 data bytes ^C --- 8.8.8.8 ping statistics --- 19 packets transmitted, 0 packets received, 100% packet loss root@triorail-phyboard-pollux-imx8mp-3:~# qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-get-packet-statistics [/dev/cdc-wdm0] Connection statistics: TX packets OK: 1 RX packets OK: 2 TX packets dropped: 0 RX packets dropped: 0 TX bytes OK: 79 RX bytes OK: 223 root@test-phyboard-pollux-imx8mp-3:~# Packet statistics does not see my sent "TX packets"... I see the outgoing packets on root@test-phyboard-pollux-imx8mp-3:~# tcpdump -i wwan0 tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on wwan0, link-type RAW (Raw IP), snapshot length 262144 bytes 06:09:34.870791 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 0, length 64 06:09:35.871287 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 1, length 64 06:09:36.871728 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 2, length 64 06:09:37.871891 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 3, length 64 06:09:38.872373 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 4, length 64 06:09:39.872843 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 5, length 64 06:09:40.873290 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 6, length 64 06:09:41.873740 IP 192.0.0.2 > dns.google: ICMP echo request, id 29726, seq 7, length 64 06:09:59.055705 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b6:39:cb:24:ba:d2 (oui Unknown), length 318 06:11:03.278826 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b6:39:cb:24:ba:d2 (oui Unknown), length 318 06:12:06.785606 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b6:39:cb:24:ba:d2 (oui Unknown), length 318 06:13:10.620266 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b6:39:cb:24:ba:d2 (oui Unknown), length 318 06:14:14.162927 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b6:39:cb:24:ba:d2 (oui Unknown), length 318 06:15:17.190064 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from b6:39:cb:24:ba:d2 (oui Unknown), length 318 06:15:55.451557 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 0, length 64 06:15:56.452021 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 1, length 64 06:15:57.452453 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 2, length 64 06:15:58.452888 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 3, length 64 06:15:59.453035 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 4, length 64 06:16:00.453468 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 5, length 64 06:16:01.453912 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 6, length 64 06:16:02.454560 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 7, length 64 06:16:03.455017 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 8, length 64 06:16:04.455342 IP 192.0.0.2 > dns.google: ICMP echo request, id 30052, seq 9, length 64 ^C 24 packets captured 24 packets received by filter 0 packets dropped by kernel root@test-phyboard-pollux-imx8mp-3:~# Checking again: root@test-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --wda-get-data-format [/dev/cdc-wdm0] Successfully got data format QoS flow header: no Link layer protocol: 'raw-ip' Uplink data aggregation protocol: 'qmap' Downlink data aggregation protocol: 'qmap' NDP signature: '0' Downlink data aggregation max datagrams: '1' Downlink data aggregation max size: '8192' root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip Y root@test-phyboard-pollux-imx8mp-3:~# Do I need a call to --wds-bind-data-port ? So I assume routing of data packet to radio module is working, outgoing packets arrive at radio module, but radio module is still in some mode, where it assumes a different packet format than the host sends? Best regards, Martin Am 17.08.2025 um 21:12 schrieb Martin Maurer: <blockquote type="cite">Hello, due to a bug with USB3 and default settings, I am currently trying to establish a connection with QMAP enabled. (see my previous message here in this mailing list) I don't need multiple connections, one fast stable connection is enough for the moment. It looks like qmimux is not enabled in my used Linux kernel(s). I hope my current test work also without it? I can set QMAP mode, able to establish an Internet connection, but ping is not working. See here what I am doing: (I repeated some command, just to be sure, the settings are still there like I set before) root@test-phyboard-pollux-imx8mp-3:~# qmicli --version qmicli 1.36.0 Copyright (C) 2012-2023 Aleksander Morgado License GPLv2+: GNU GPL version 2 or later <a class="moz-txt-link-rfc2396E" href="http://gnu.org/licenses/gpl-2.0.html"><http://gnu.org/licenses/gpl-2.0.html></a> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. root@test-phyboard-pollux-imx8mp-3:~# root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip N root@test-phyboard-pollux-imx8mp-3:~# echo Y | tee /sys/class/net/wwan0/qmi/raw_ip Y tee: /sys/class/net/wwan0/qmi/raw_ip: Device or resource busy root@test-phyboard-pollux-imx8mp-3:~# ip link set wwan0 down root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip N root@test-phyboard-pollux-imx8mp-3:~# echo Y | tee /sys/class/net/wwan0/qmi/raw_ip Y root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip Y root@test-phyboard-pollux-imx8mp-3:~# ip link set wwan0 up root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip Y root@test-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --wda-get-data-format error: couldn't create client for the 'wda' service: CID allocation failed in the CTL client: Transaction timed out => First QMI transaction seems to be always timeout out (but not relevant for my question, just doing command again...) root@test-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --wda-get-data-format [/dev/cdc-wdm0] Successfully got data format QoS flow header: no Link layer protocol: 'raw-ip' Uplink data aggregation protocol: 'disabled' Downlink data aggregation protocol: 'disabled' NDP signature: '0' Downlink data aggregation max datagrams: '0' Downlink data aggregation max size: '0' root@test-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --wda-set-data-format="link-layer-protocol=raw-ip,ul-protocol=qmap,dl-protocol=qmap,dl-datagram-max-size=8192,ep-type=hsusb,ep-iface-number=4,ul-datagram-max-size=8192" [/dev/cdc-wdm0] Successfully set data format QoS flow header: no Link layer protocol: 'raw-ip' Uplink data aggregation protocol: 'qmap' Downlink data aggregation protocol: 'qmap' NDP signature: '0' Downlink data aggregation max datagrams: '1' Downlink data aggregation max size: '8192' Uplink data aggregation max datagrams: '1' Uplink data aggregation max size: '8192' root@test-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --wda-get-data-format [/dev/cdc-wdm0] Successfully got data format QoS flow header: no Link layer protocol: 'raw-ip' Uplink data aggregation protocol: 'qmap' Downlink data aggregation protocol: 'qmap' NDP signature: '0' Downlink data aggregation max datagrams: '1' Downlink data aggregation max size: '8192' => I have set downlink and uplink parameter. They are outputted with "set", but "get" does not display "uplink". Just printing missing? Error in libqmi? root@test-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --wda-get-data-format [/dev/cdc-wdm0] Successfully got data format QoS flow header: no Link layer protocol: 'raw-ip' Uplink data aggregation protocol: 'qmap' Downlink data aggregation protocol: 'qmap' NDP signature: '0' Downlink data aggregation max datagrams: '1' Downlink data aggregation max size: '8192' root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip Y root@test-phyboard-pollux-imx8mp-3:~# Some queries just to be sure, the parameters are now like they were set... root@test-phyboard-pollux-imx8mp-3:~# ./connection_up.sh CID=15 [/dev/cdc-wdm0] Network started Packet data handle: '3800235120' [/dev/cdc-wdm0] Client ID not released: Service: 'wds' CID: '15' => Shell script which gets a WMD-CID, start-network, and printing some commands which could be the next commands but must be manually entered -> just for testing! rem qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-get-current-settings rem ip link set dev wwan0 down rem ip addr add 192.0.0.2 dev wwan0 rem ip link set mtu 1472 dev wwan0 rem ip link set dev wwan0 up rem ping -4 -I wwan0 8.8.8.8 root@test-phyboard-pollux-imx8mp-3:~# qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-get-current-settings [/dev/cdc-wdm0] Current settings retrieved: IP Family: IPv4 IPv4 address: 192.0.0.2 IPv4 subnet mask: 255.255.255.224 IPv4 gateway address: 192.0.0.1 IPv4 primary DNS: 192.0.0.30 MTU: 1472 Domains: none => seems to be correct, parameters like I have seen earlier root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip Y => still ok, good! root@test-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --wda-get-data-format [/dev/cdc-wdm0] Successfully got data format QoS flow header: no Link layer protocol: 'raw-ip' Uplink data aggregation protocol: 'qmap' Downlink data aggregation protocol: 'qmap' NDP signature: '0' Downlink data aggregation max datagrams: '1' Downlink data aggregation max size: '8192' => still ok root@test-phyboard-pollux-imx8mp-3:~# ip link set dev wwan0 down root@test-phyboard-pollux-imx8mp-3:~# ip addr add 192.0.0.2 dev wwan0 root@test-phyboard-pollux-imx8mp-3:~# ip link set mtu 1472 dev wwan0 root@test-phyboard-pollux-imx8mp-3:~# ip link set dev wwan0 up root@test-phyboard-pollux-imx8mp-3:~# ping -4 -I wwan0 8.8.8.8 PING 8.8.8.8 (8.8.8.8): 56 data bytes ^C --- 8.8.8.8 ping statistics --- 22 packets transmitted, 0 packets received, 100% packet loss => This is my current problem. Ping is not working with "qmap" enabled. Without qmap, I have an error with USB3 under certain (rare) circumstances. root@test-phyboard-pollux-imx8mp-3:~# cat /sys/class/net/wwan0/qmi/raw_ip Y => still ok root@test-phyboard-pollux-imx8mp-3:~# ping -4 -I wwan0 8.8.8.8 PING 8.8.8.8 (8.8.8.8): 56 data bytes ^C --- 8.8.8.8 ping statistics --- 14 packets transmitted, 0 packets received, 100% packet loss => Also second try it not working root@test-phyboard-pollux-imx8mp-3:~# Is QMAP perhaps needing qmimux for sure, and I must then add qmimux1 and work over this? So wwan0 is then not working anymore when activating QMAP? As far as I remember there are different ul/dl-protocols. Is "qmap" the right one? Or do I need "qmapv5"? What is the difference? ul-protocol (disabled|tlp|qc-ncm|mbim|rndis|qmap|qmapv5), dl-protocol (disabled|tlp|qc-ncm|mbim|rndis|qmap|qmapv5) /: Bus 002.Port 001: Dev 001, Class=root_hub, Driver=xhci-hcd/1p, 5000M |__ Port 001: Dev 002, If 0, Class=[unknown], Driver=option, 5000M |__ Port 001: Dev 002, If 1, Class=[unknown], Driver=option, 5000M |__ Port 001: Dev 002, If 2, Class=[unknown], Driver=option, 5000M |__ Port 001: Dev 002, If 3, Class=[unknown], Driver=option, 5000M |__ Port 001: Dev 002, If 4, Class=[unknown], Driver=qmi_wwan, 5000M I use a Quectel RM520N-GL for this test. If is 4. Is ep-iface-number=4 correct? "ep" for it is I think higher like 0x07 or even 0x14??? Are my used numbers (sizes and datagrams dl/up) useable for my use case? Or do I need to take different ones? Many thank! Best regards, Martin </blockquote> </blockquote> </body> </html>