Use NCM USB Dongle for WAN connection

NCM (Network Control Model) is ethernet over USB protocol used by some fast speed USB modems/dongles.

For more information about different protocols used:

• ppp, see How to use 3g/UMTS USB Dongle for WAN connection
• qmi and mbim, see How to use LTE modem in QMI mode for WAN connection
• rndis, see How to use LTE modem in RNDIS mode for WAN connection

You need to switch modem to provide native NCM interface instead of Modem interface.

Please read about AT commands for your modem.

Once you've done - you can disconnect modem from the PC and connect it to the router.

1. Install OpenWRT

2. Complete steps OpenWrt Configuration

Router should be turned on and connected to the Internet to get the needed packages. Please refer to: Internet Connection.

To make use of NCM protocol, package kmod-usb-net-huawei-cdc-ncm and comgt-ncm are needed.

• usb-modeswitch - It will automatically issue a “special” command to the modem for switching it into the “Working” state

opkg update
opkg install comgt-ncm kmod-usb-net-huawei-cdc-ncm usb-modeswitch

1. Add support for PC Interface (ttyUSB0)

• kmod-usb-serial
• kmod-usb-serial-option
• kmod-usb-serial-wwan

opkg update
opkg install kmod-usb-serial kmod-usb-serial-option kmod-usb-serial-wwan

3. Add support for FlashCard of your dongle - refer to: USB Storage

1. Install all the needed packages

opkg update
opkg install comgt-ncm luci-proto-3g luci-proto-ncm luci-proto-qmi kmod-usb-net-huawei-cdc-ncm usb-modeswitch

If your have not enough space on your device - think of installing Rootfs on External Storage (extroot)

Another option is Hardware memory upgrade. Refer to your router Forum thread for possibility and instructions.

2. Reboot the router

reboot

3. Check that everything is OK and you got new device:

ls -l /dev/cdc-wdm0

crw-r--r--    1 root     root      180, 176 Oct  1 12:03 /dev/cdc-wdm0

If you have no such device - try to find out what went wrong:

try dmesg to read kernel logs on USB init

dmesg

or look info about USB devices and interfaces present in the system:

cat /sys/kernel/debug/usb/devices

...
T:  Bus=03 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  2 Spd=480  MxCh= 0
D:  Ver= 2.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=12d1 ProdID=1506 Rev= 1.02
S:  Manufacturer=HUAWEI_MOBILE
S:  Product=HUAWEI_MOBILE
C:* #Ifs= 5 Cfg#= 1 Atr=80 MxPwr=  2mA
I:* If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=03 Prot=10 Driver=(none)
E:  Ad=82(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=03 Prot=12 Driver=option
E:  Ad=83(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:  If#= 2 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=03 Prot=16 Driver=huawei_cdc_ncm
E:  Ad=85(I) Atr=03(Int.) MxPS=  16 Ivl=2ms
I:* If#= 2 Alt= 1 #EPs= 3 Cls=ff(vend.) Sub=03 Prot=16 Driver=huawei_cdc_ncm
E:  Ad=85(I) Atr=03(Int.) MxPS=  16 Ivl=2ms
E:  Ad=84(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E:  Ad=86(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS= 512 Ivl=125us
I:* If#= 4 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E:  Ad=87(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=05(O) Atr=02(Bulk) MxPS= 512 Ivl=125us

...

See Troubleshooting Section of this page for more information.

UCI is supporting NCM network protocol configuration.

The package comgt-ncm + modem specific driver must be installed to use NCM.

You can configure UCI manually using uci command line or text editor or with Luci package luci-proto-ncm.

If you are using option mode, an AT command setting the mode is sent to modem on every connection. Most of modems (at least all Huawei models) store this setting in internal flash. So on each connection Openwrt writes to modem flash. It is recommended to remove this option after a required mode is set once.

Now you should add new Interface to /etc/config/network

config interface 'wwan'
        option proto 'ncm'
        option ifname 'wwan0'
        option device '/dev/cdc-wdm0'
        option apn 'internet'
        option mode 'preferlte'
        option pincode '0000'
        option delay '5'

You can do this using the vi text editor, but if you're not comfortable with that, point your browser to 192.168.1.1 again, choose Network → Interfaces and click Add new interface.

Write wwan as the name of the interface and make it cover the wwan0 interface. Choose ncm as the protocol.

Insert a screenshot of LUCI add Interface.

The only thing that is left - Add wwan interface to WAN zone

Using LUCI:

• go to Network → Firewall, scroll down to wan and click the Edit button
• add a checkmark to the wwan box under Covered networks heading, click Save & Apply

Insert a Screen Shot from LUCI.

Some providers of the cellular internet use redirection to their pages for access activation, when you are connected first time. I.e. YOTA in Russia.

Normally this would be blocked by dnsmasq:

Jan 18 14:36:49 OpenWrt daemon.warn dnsmasq[1325]: possible DNS-rebind attack detected: my.yota.ru

You have 2 options:

• Allow rebind responses RFC1918 (In LUCI goto Network → DHCP and DNS and uncheck Rebind protection checkmark)
• Add Yota.ru domain to Whitelist (In LUCI goto Network → DHCP and DNS and type in “yota.ru” without quotes to the Domain whitelist field.

Save & apply

Try the following commands:

usbmode -l

It should respond with a message about your USB device is detected. If it does, issue the next command. If it doesn't, you might want to get help from the forum.

usbmode -s

Then wait for the dongle to get issued an IP from your ISP.

Include the following codes into /etc/rc.local just before exit 0:

/sbin/usbmode -l
/bin/sleep 2
/sbin/usbmode -s

This script GitHub oilervoss will check the connection pinging a public IP and, under failure, it will send AT commands to the serial interface of the modem restarting it.

To achieve continuous monitoring of the connection, it must be called recurrently through a cron job as:

#/etc/crontabs/root
#min    h   day  mon  week  command
*/20    *    *    *    *    /etc/init.d/ncm-fix start

This is probably related to ticket #18673 (https://dev.openwrt.org/ticket/18673). You should be able to use the modem by starting ndis manually by sending the following to /dev/ttyUSB1

AT^NDISDUP=1,1,"your_apn_address"

It is possible to automate this task using hotplug. Below are some scripts fetched from http://forum.ixbt.com/post.cgi?id=print:14:59307&page=4. Do not forget to modify them to your needs. The scripts are for Huawei modems obviously.

/etc/init.d/ncm-network:

#!/bin/sh /etc/rc.common

#
DEVICE='/dev/ttyUSB1'
# Interface name from /etc/config/network
IFNAME='WWAN'
# Your APN:
APN='your_apn_here'

START=70
STOP=90

start() {
        if [ -e ${DEVICE} ]; then
                echo -ne "AT^NDISDUP=1,0\r\n" > ${DEVICE}
                sleep 3
                echo -ne "AT^NDISDUP=1,1,\"${APN}\"\r\n" > ${DEVICE}
                sleep 3
                ifup $IFNAME
        else
                echo "No such device ${DEVICE}" | logger -t "ncm-network[$$]" -p info
        fi
}

stop() {
        if [ -e ${DEVICE} ]; then
                ifdown $IFNAME
                sleep 3
                echo -ne "AT^NDISDUP=1,0\r\n" > ${DEVICE}
        else
                echo "No such device ${DEVICE}" | logger -t "ncm-network[$$]" -p info
        fi
}

/etc/hotplug.d/usb/70-ncm-network

#!/bin/sh

# Uncomment set line below and check your modalias I from tmp file
MODEM_ID='usb:v12D1p1506d0102dc00dsc00dp00ic08isc06ip50in05'
PAUSE=10
PAUSE_FOR_HOTPLUG=5

#set >> /tmp/ncm-network.debug

if [ "${MODALIAS}" != "${MODEM_ID}" ]; then
        exit 0
fi

case "$ACTION" in
        add)
                SYSTEM_UPTIME=$(cat /proc/uptime | awk -F"\." '{ print $1 }')
                if [ "${SYSTEM_UPTIME}" -gt 60 ]; then
                        PAUSE=$PAUSE_FOR_HOTPLUG
                fi
                {
                sleep ${PAUSE} && \
                echo "Start modem ${MODEM_ID}" | logger -t "hotplug[$$]" -p info && \
                /etc/init.d/ncm-network start
                } &
                ;;
        remove)
                echo "Stop modem ${MODEM_ID}" | logger -t "hotplug[$$]" -p info
                /etc/init.d/ncm-network stop
                ;;
esac

Some modems does not reconnect after losing connection. Here is a connection check sh script which checks if it can ping remote servers with time intervals. If all pings fail, it tries to start the network by executing /etc/init.d/ncm-network start

#!/bin/sh

# Enter the FQDNs you want to check with ping (space separated)
# Script does nothing if any tries to any FQDN succeeds
FQDN="www.google.com"
FQDN="$FQDN www.amd.com"
FQDN="$FQDN www.juniper.net"

# Sleep between ping checks of a FQDN (seconds between pings)
SLEEP=3                         # Sleep time between each retry
RETRY=3                         # Retry each FQDN $RETRY times
SLEEP_MAIN=60                   # Main loop sleep time

check_connection()
{
  for NAME in $FQDN; do
    for i in $(seq 1 $RETRY); do
      ping -c 1 $NAME > /dev/null 2>&1
      if [ $? -eq 0 ]; then
        return 0
      fi
      sleep $SLEEP
    done
  done
  # If we are here, it means all failed
  return 1
}

while true; do
  check_connection
  if [ $? -ne 0 ]; then
    /etc/init.d/ncm-network start
  fi
  sleep $SLEEP_MAIN
done

If your SIM receives a voice call. It will downgrade to CS network which means you will downgrade into 3G mode. To avoid this, set the stick to use only PS network by creating `/etc/hotplug.d/iface/99-ifupwwan` file with following code. Make sure to modify it to use correct serial interface and correct AT command for your device.

[ "$ACTION" = "ifup" -a "$INTERFACE" = "wwan" ] && {
    logger "iface wwan up detected..."
    # We need to set this to stop the card from receiving phone calls
    # This is for EC-25
    #echo -ne "\r\nAT+QCFG=\"servicedomain\",1,1\r\n" > /dev/ttyUSB2
    # This is for Huawei
    echo -ne "\r\nAT^SYSCFGEX=\"00\",3FFFFFFF,1,1,7FFFFFFFFFFFFFFF,,\r\n" > /dev/ttyUSB2
}