Citrix SD-WAN

Configure external USB LTE modem

You can connect an external 3G/4G USB modem on certain Citrix SD-WAN appliances. The appliances use the 3G/4G network along with other connections to form a virtual network that aggregates bandwidth and provides resiliency. If there is a connectivity failure on the other interfaces, traffic is automatically redirected through the USB LTE modem. The following appliances support an external USB modem:

  • Citrix SD-WAN 210 SE / AE
  • Citrix SD-WAN 210 SE LTE
  • Citrix SD-WAN 110 SE
  • Citrix SD-WAN 110 Wi-Fi SE
  • Citrix SD-WAN 110 LTE Wi-Fi SE
  • Citrix SD-WAN 1100 SE / PE / AE
  • Citrix SD-WAN 2100 SE / PE

The Citrix SD-WAN 210 SE LTE and Citrix SD-WAN 110 LTE Wi-Fi SE appliances have a built-in LTE modem. Active dual LTE is supported on these appliances.

The following appliances do not support an external USB modem:

  • Citrix SD-WAN 1000 SE / PE
  • Citrix SD-WAN 2000 SE / PE
  • Citrix SD-WAN 4000 SE

CDC Ethernet, MBIM, and NCM are the three types of external USB modems supported. You can configure the APN settings and Enable/Disable modem on MBIM and NCM USB modems. Mobile broadband operations are not supported on CDC Ethernet USB modems.


The external LTE dongles with modem type as MBIM do not work on Citrix SD-WAN 2100 platform.

Connecting the USB modem

Enable and test the USB modem according to the guidelines provided by your wireless carrier.

Perquisites for external LTE modem:

  • Use the supported USB LTE dongles. The supported dongle hardware models are Verizon USB730L and AT&T USB800.
  • Ensure that a SIM card is inserted into the USB LTE dongle. The CDC Ethernet LTE dongles are pre-configured with a static IP address, this interferes with the configuration and cause connection failure or intermittent connection, if the SIM card is not inserted.
  • Before inserting a CDC Ethernet LTE dongle into the SD-WAN appliance, connect the external USB stick to a Windows/Linux machine and ensure that the internet is working properly with proper APN and Mobile Data Roaming configuration. Ensure that the Connection mode of the USB dongle is changed from the default value Manual to Auto.


  • The Citrix SD-WAN appliances support only one USB LTE dongle at a time. If more than one USB dongle is plugged in, unplug all the dongles and plug in only one dongle.
  • The Citrix SD-WAN appliances do not support user name and password for USB modems. Ensure that the user name and password feature are disabled on the modem during setup.
  • Unplugging or rebooting an external MBIM dongle impacts the internal LTE modem data session. This is an expected behavior.
  • When an external LTE modem is plugged-in, the SD-WAN appliance takes about 3 minutes to recognize it.

To view the external modem details, in the appliance UI navigate to Configuration > Appliance Settings > Network Adapters > Mobile Broadband. Select External Modem as the modem type.

Status information


The LTE USB dongle model number is not displayed in Status Info section.

Mobile broadband operations

Operations that are supported on CDC Ethernet and MBIM / NCM external modems:

Operations External modem - CDC Ethernet External modem - MBIM and NCM
SIM preference No No
APN settings No Yes
Network settings No No
Roaming No No
Manage firmware No No
Enable/Disable modem No Yes
Reboot modem No No
Refresh SIM No No

You can remotely view and manage all the LTE sites in your network using the Citrix SD-WAN Center. For more information see, Remote LTE site management.

Configure the external USB modem

To configure an external USB modem, in the Configuration Editor navigate to Sites, select a site, and click Interface Groups. The external USB modem interface LTE-E1 is available to be configured. For more information on configuring a branch for LTE, see Configure branch for LTE.

LTE-E1 interface

Zero-touch deployment over LTE

Pre-requisites for enabling zero-touch deployment service over USB LTE modem:

  • Insert the USB modem in the Citrix SD-WAN appliance. For more information, see Connecting the USB modem.
  • Ensure that the SIM card on the USB modem has an activated data plan.
  • Ensure that the management/data port is not connected. If the management/data port is connected, disconnect it.
  • Ensure that the appliance configuration has the internet service defined for the LTE interface.

When the appliance is powered ON, the zero-touch deployment service uses the LTE-E1 port to obtain the latest SD-WAN software and configuration.

Use the SD-WAN Center GUI to deploy and configure the appliance for the zero-touch deployment service. For more information, see Zero Touch Deployment. For information about zero-touch deployment through the SD-WAN Orchestrator see, Zero Touch Deployment.

Supported USB modems

The following modems are compatible with Citrix SD-WAN appliances.


Citrix does not control the wireless carrier firmware updates. Therefore compatibility of new modem firmware to Citrix SD-WAN software is not guaranteed. The customer controls the modem firmware update. Citrix recommends testing a firmware update on a single site before pushing it across the entire network.

Region Wireless Carrier/ Manufacturer USB Modem Modem Type Supported Interfaces
USA Verizon Global Modem USB730L cdc_ether 4G only
USA AT&T AT&T Global Modem USB800 cdc_ether 4G only

AT commands

AT commands help in monitoring and troubleshooting LTE modem configuration and status. AT is the abbreviation for ATtension. As every command line starts with at, they are called AT commands. Citrix SD-WAN platform models that support LTE support running AT commands. AT commands are modem specific and therefore the list of AT commands varies across the platforms.

To run AT commands, perform the following steps:

  1. Log into the Citrix SD-WAN appliance console.
  2. At the prompt, type the user name and password to gain CLI interface access.
  3. At the prompt, type lte.
  4. Enter at and then enter the AT command.

The following is an example:

at at+cpin – Provides SIM status information.

LTE AT SIM status command

Configure external USB LTE modem