LTE issue after 7.20.1 -> 7.23.3 (wants ARP, not possible)

RouterOS General
1

SIMCOM_SIM7600G-H , revision: LE20B04SIM7600G22

updated from 7.22.x ~7.20.1, it was working fine before. according to claude's diagnosis, "The modem transmits with src-mac=00:00:00:00:00:00 and advertises a synthetic gateway (address + 1), so it cannot answer ARP. RouterOS transmits ARP requests anyways, the entries go to failed, and /ip/arp/add ... interface=lte1 is rejected with "target device does not support arp".

I verified it's indeed correct. under lte1, attempting to add static ARP entry fails, but it has other failed ARP attempts. I tried setting mode to mbim/serial, did some attempts with usb/serial, ppp etc., it also didn't work although I guess that's my module's incapability.

anyone else having the same issue? I searched the forum but couldn't find the same issue, so maybe it's specific to my cheap knockoff dongle.

2

quick update, it was on mode 9001 (NDIS), I switched to 9003 (MBIM), after that it sets up routes fine and worked. I thought 'mode: auto/mbim/serial' meant there are two options, to my understanding neither were used, and with update there was a change that broke 'ndis mode'

this was useful: Waveshare SIM7600G-H 4G DONGLE - anyone got this to work? - #14 by kilburnflyer

3

TY !!!!!!
you saved my ass

i have SIMCOM_SIM7600CE-T
mPCIe
x86 PC Engines apu3

anything beyond 7.20.8 was dead
after dozen of RIF and mails with support, we could not solve this

but now, your post made it work !!!
at least, i need to use 9011

/interface/lte/at-chat lte1 input="AT+CUSBPIDSWITCH=9011,1,1"

4

PID configuration:
9000:Diag, NMEA, At, Modem, Audio, Rmnet
9001:Diag, NMEA, At, Modem, Audio, Rmnet
9002:Diag, NMEA, At, Modem, Audio, Rmnet
9003:Diag, NMEA, At, Modem, Audio, MBIM
9004:Diag, NMEA, At, Modem, Audio, GNSS, Rmnet
9005:Diag, NMEA, At, Modem, Audio, GNSS, MBIM
9006:Diag, NMEA, At,Modem
9007:Diag, NMEA, At, Modem, Audio, Rmnet,mass_storage
9011:RNDIS,Diag, NMEA, At, Modem, Audio
9016:Diag, Rmnet
9018:Diag, NMEA, At, Modem, Audio, Ecm
9019:RNDIS
901A: Diag, NMEA, At, Rmnet
901B:NMEA, At, Rmnet
9020: Diag, At, Modem
9021: Diag, Modem
9022: Diag, Modem, Rmnet
9023: Modem
9024: At, Modem
9025: Modem,rmnet
9026: Modem,Audio
9027: Modem,Audio, Rmnet
9028:Diag, Modem,Audio, Rmnet
9029:Diag, Modem,Audio
902A: At
902B: Diag, NMEA, At, Modem, Rmnet,Usb-audio

5

glad to see it helped someone else. still not sure if 'ndis support' is a bug or a feature, couldn't find any documentation on it

you made me realize, my routeros version was older since it was main router - from previous logs I see "RouterOS 7.20.1" - so I guess it's broken around the versions you mentioned.

according to claude:

7.21: usb - "LTE modem and USB-Serial Controller enumeration fix"

Enumeration is precisely the step that decides whether composition 9001 gets claimed as a raw-IP point-to-point interface (correct for NDIS, the pre-7.21 behaviour) or as a CDC-Ethernet device with a MAC address and a DHCP client (the bug).

6

only drawback of 9011 RNDIS is that all cell info is missing from GUI, so user is blind about snr/signal/etc

but at least it working ... maybe one day MT will fix this :slight_smile: