tags: QMI QUECTEL EG18-NA (2024-08 firmware, more recent than the stock netgear, which has helped)
IF I leave everything alone on the default QMI connection to the internal quectel modem, and only change the openwrt default of ipv4 to ipv4/6 so I can properly connect to sites like download.openwrt.org and pass ipv6 tests, it's a decent connection for what it is in terms of reliability.
HOWEVER, if I go to Network, Interfaces, Device, WWAN0 (the device the qmi / quectel interface uses) and change the IP4 & 6 MTU's to the recommended 1420 for the provider (verizon), the cell connection is very difficult to make, if at all.
What seems to be happening, is somehow Openwrt is forwarding the MTU information to the quectel modem, and it causes the quectel to become unstable/unusable. It's not the actual value set on the MTU, but that it's set to anything at all.
It seems that way, that Openwrt is pushing the MTU value to the quectel and it's dying. It won't connect properly unless I 'unconfigure' the wwan0 device. Here's an idea: is there something I should program on the Quectel first (using picocom/AT commands) for the MTU to be 1420? Could it be that Openwrt is setting that device's MTU to 1420 and then it no longer matches what the Quectel is using, and the issue is there?
Would appreciate feedback, thanks!
brada4
2
You have to talk to your provider. 4/5g underlying tech can transport 2kB-10kB frames