[OpenWrt-Devel] Huawei 3372 NCM support on CC not working

Bjørn Mork bjorn at mork.no
Wed Jul 1 10:03:53 EDT 2015

chrono <chrono at open-resource.org> writes:

> ### test flow ###
> echo -e "AT^NDISDUP=1,1,\"internet.eplus.de\",\"eplus\",\"gprs\"\r" >
> /dev/ttyUSB1
> AT^NDISDUP=1,1,"internet.eplus.de","eplus","gprs"
> OK
> ^NDISSTAT:1,,,"IPV4"
> ^RSSI:19
> ^HCSQ:"LTE",47,40,126,20
> ^DSFLOWRPT:00000002,00000000,00000000,0000000000000000,0000000000000000,00000000,00000000
> ^DSFLOWRPT:00000004,00000000,00000000,0000000000000000,0000000000000000,00000000,00000000
> ^DSFLOWRPT:00000006,00000000,00000000,0000000000000000,0000000000000000,00000000,00000000
> ^DSFLOWRPT:00000008,00000000,00000000,0000000000000000,0000000000000000,00000000,00000000
> ^DSFLOWRPT:0000000A,00000000,00000000,0000000000000000,0000000000000000,00000000,00000000
> +COPS: 0,0,"MEDIONmobile",7
> OK
> echo -e "AT^DHCP?\r" > /dev/ttyUSB1
> ^DHCP:
> F8C9730A,F0FFFFFF,F1C9730A,F1C9730A,096717D4,086717D4,150000000,150000000
> perl -e 'print join(",",map { join(".", unpack("C4", pack("L", hex)))
> } split /,/, shift),"\n"'
> F8C9730A,F0FFFFFF,F1C9730A,F1C9730A,096717D4,086717D4
> ifconfig wwan0 netmask
> ping

Great docs of what you have tried!

There are two more things I can think of that is worth testing:
1) set the wwan0 interface up before connecting (AT^NDISDUP):
     ifconfig wwan0 up
2) turn off ARP:
     ifconfig wwan0 -arp

And note that pinging the "gateway" isn't a good test, contrary to
normal networks.  The "subnet" and "gateway" are faked by the firmware.
In reality, the gateway address is probably assigned to another user. If
the firmware does things properly, then it won't answer the ping but
forward those icmp echo requests to the mobile network like any other
packet.  And many mobile networks will never forward icmp echo to end
users, so you will not get a reply even if the address happens to be in
use by someone.

To test this you should find some address which is known to be reachable
and responding, and add a route to that (or a default route). I.e.
 ip route add via
 ip route add default via

If you turn off arp then you can simply ignore the gateway address and
refer to the netdev instead:
  ip route add dev wwan0
  ip route add default dev wwan0

Then try to ping (or whatever address you chose).

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