Wwan not getting an IP

General questions
#1

Hello all -
I have a USB LTE modem (Telit LM960A18) that works great when it’s simply plugged into another device. When it’s plugged into my vyos box, I can get an IP if I use udhcpc -i wwan0.

For some reason, when using the configure shell and I set wwan0 address dhcp, it will not get an ip address.

I have the apn set, and I have the address set to dhcp, but no IP ever shows up when I do a “show interfaces.”

I know I must be missing something simple here, but I have no idea what it may be.
Anyone know where I may be going wrong here?

TIA

Sierra Wireless MC7455 and no Comms Drivers
#2

Hello @reno138
I haven’t had any experience with USB LTE modems on VYOS, but it looks interesting to get any log or debugging information. I saw some user guidance for this modem on his official site, try to follow it

#3

Hello all,

Glad to see VyOS LTE4 wwan development is progressing again! It almost works however:

I can confirm the same problem for both Telit LM940 and a Sierra Wireless MC7455 card.

The LTE modem seems to expect Link layer protocol: ‘raw-ip’ and not the Ethernet type.

root@vyos:~# qmicli --device=/dev/cdc-wdm0 --device-open-proxy --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'

After starting:

dhclient -4 -nw -cf /var/lib/dhcp/dhclient_wwan0.conf -pf /var/lib/dhcp/dhclient_wwan0.pid -lf /var/lib/dhcp/dhclient_wwan0.leases wwan0

fails with an:

Unsupported device type 65534 for “wwan0”

This was tested using:

Version:          VyOS 1.4-rolling-202111090317
Release train:    sagitta

Built by:         autobuild@vyos.net
Built on:         Tue 09 Nov 2021 03:17 UTC
Build UUID:       65b8318e-dbe2-4856-a090-cefd6713891d
Build commit ID:  ee81272116cd68

Config:

interfaces {
    wwan wwan0 {
        address dhcp
        apn internet.access.nl
    }
}

I suspect that dhclient does not support Link layer protocol: ‘raw-ip’ for IPv4.

Question: Does anyone know how to reconfiger/change firmware a LTE modem cards to change from raw-ip to a different supported format like Ethernet 802.3?
Alternatively: some users switch to a different dhcp client udhcp but that is probably not what Vyos wants to support.

More discussion: debian - DHCP client fails to get IP address (Modem EM7430) - Unix & Linux Stack Exchange

Kinds regards,
Paul.

#4

Hi all,
didn’t try any of your configs, but all i know is that Data LTE is just a fancy DialUpSerialLine that needs PPP to do all his IP configurations.
At least in my setup with pfsense i use PPP interfaces.
Cheers and good luck
C

#5

It seems as if VyOS only executes mmcli --modem 0 --simple-connect when bringing up the wwan interface. According to the NetworkManager mailing list this is not enough, since it’s typically NetworkManager’s job to trigger mmcli and then set up the IP address once the connection has been established. You can see the current status, including the assigned IP address, prefix, gateway, DNS by checking the currently connected bearer with mmcli --bearer 0. When I look through the source code of VyOS there is no handling of this information happening anywhere. The “dhcp” option in the configuration is only used to decide what type of IP address (4/6) to request from the cell provider.