# Add Modem Interfaces for Single Engines

A Modem Interface represents the settings of a mobile broadband modem that provides a wireless link from a Single Engine to the Internet or to the Management Server. You can optionally define one or more Modem Interfaces for each Single Engine.

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For more details about the product and how to configure features, click Help or press F1.

## Steps

1. Right-click a Single Engine, then select Edit Single Engine.
2. In the navigation pane on the left, select Interfaces.
3. Right-click the empty space, then select New > Modem Interface.
4. Define the basic Modem Interface properties.
5. If necessary, define the contact address information.
   If components from some Locations cannot use the Default contact address, click Exceptions to define Location-specific contact addresses.
6. Click OK.
7. If you are configuring a new Single Engine, or if you want to change the roles the different interfaces have in the configuration, select system communication roles for engine interfaces.
8. Otherwise, update the routing configuration and transfer the changes to the engine.
   1. Select Routing in the navigation pane on the left.
   2. Adjust the routing configuration as necessary.
   3. Click Save and Refresh.

## Modem Interface Properties dialog box (Engine)

Use this dialog box to configure properties for Engine Modem Interfaces.

Option | Definition
--- | ---
General tab
Modem Type | Select the type of mobile broadband modem that was delivered with your appliance.
Modem Number | Select the modem number to represent the modem in the configuration.
Zone (Optional) | Select the network zone to which the interface belongs. Click Select to select an element, or click New to create an element.
DHCP Index | The DHCP index is a number for your own reference to identify the DHCP interface.
PIN Code (Optional) | Enter the PIN code if it is needed for the modem’s SIM card. If the PIN code is included in the configuration and you change the modem’s SIM card after configuring the Engine, you must change the PIN code.
Access Point Name | The access point name provided by your service provider.
Phone Number (Optional) | (When Modem Type is 3G Modem) If a dialing prefix is required, enter the modem’s dialing prefix.
Service Name | (When Modem Type is 3G Modem) The service name provided by your service provider.
Auth Method (Optional) | (When Modem Type is LTE Modem) The authentication method used by the service provider. No Authentication PAP — Password Authentication Protocol. CHAP — Challenge-Handshake Authentication Protocol. MSCHAPV2 — Microsoft version of the CHAP protocol.
Username | (When Modem Type is 3G Modem or when an authentication method is selected ) The user name provided by your service provider.
Password | (When Modem Type is 3G Modem or when an authentication method is selected ) The password provided by your service provider. By default, passwords and keys are not shown in plain text. To show the password or key, deselect the Hide option.
Contact Addresses section (All optional settings)
Default | Used by default when a component that belongs to another Location connects to this server.
Exceptions | Allows you to define exceptions to the default contact address. Opens the Exceptions dialog box.
QoS section (When Modem Type is LTE Modem)
QoS Mode (Optional) | Select the QoS mode to apply to the link on this interface. You can select from one of the following options: No QoS: When selected, no QoS mode is enabled. QoS Statistics Only: It allows the collection of QoS Class-based counters without activating any other QoS feature. DSCP Handling and Throttling: When selected, no queues and no throttling of all traffic. Only the connections that are tagged with QoS Class are treated as per the action that is defined in the QoS policy. Full QoS: It throttles all traffic to the Interface Throughput Limit that is set in the interface properties Note: If Full QoS or DSCP Handling and Throttling is selected, a QoS policy must also be selected. If Full QoS is selected, the throughput must also be defined. If the interface is a Physical Interface, the same QoS mode is automatically applied to any VLANs created under it.
QoS Policy | (When QoS Mode is Full QoS or DSCP Handling and Throttling) The QoS policy for the link on this interface. If the interface is a Physical Interface, the same QoS policy is automatically selected for any VLANs created under it. Note: If a Virtual Resource has a throughput limit defined, the interfaces on the Virtual Engine that use a QoS policy all use the same policy. The policy used in the first interface is used for all the interfaces.
Interface Throughput Limit | (When QoS Mode is Full QoS) Enter the throughput for the link on this interface as megabits per second. If the interface is a Physical Interface, the same throughput is automatically applied to any VLANs created under it. The throughput is for uplink speed (outgoing traffic) and typically must correspond to the speed of an Internet link (such as an ADSL line), or the combined speeds of several such links when connected to a single interface. CAUTION: Make sure that you set the interface speed correctly. When the bandwidth is set, the Engine always scales the total amount of traffic on this interface to the bandwidth you defined. This scaling happens even if there are no bandwidth limits or guarantees defined for any traffic. CAUTION: The throughput for a Physical Interface for a Virtual Engine must not be higher than the throughput for the Master Engine interface that hosts the Virtual Engine. Contact the administrator of the Master Engine before changing this setting.
MTU (Optional) | (When Modem Type is LTE Modem) The maximum transmission unit (MTU) size on the connected link. Either enter a value between 400–65535 or select a common MTU value from the list. If the interface is a Physical Interface, the same MTU is automatically applied to any VLANs created under it. The default value (also the maximum standard MTU in Ethernet) is 1500. Do not set a value larger than the standard MTU, unless you know that all devices along the communication path support it. To set the MTU for a Virtual Engine, you must configure the MTU for the interface on the Master Engine that hosts the Virtual Engine, then refresh the policy on the Master Engine and the Virtual Engine.
Comment (Optional) | A comment for your own reference.
Automatic default route | Enables the automatic creation of a default route for the interface.

Option | Definition
--- | ---
Advanced (When Modem Type is LTE Modem) (All optional settings)
Override Engine's Default Settings | When selected, the default settings of the Security Engine are overridden.
SYN Rate Limits | Default — The interface uses the SYN rate limits defined for the Security Engine on the Advanced Settings branch of the Engine Editor. None — Disables SYN rate limits on the interface. Automatic — This is the recommended mode if you want to override the general SYN rate limits defined on the Advanced Settings branch of the Engine Editor. The Engine calculates the number of allowed SYN packets per second and the burst size (the number of allowed SYNs before the Security Engine starts limiting the SYN rate) based on the Engine’s capacity and memory size. Custom — Enter the values for Allowed SYNs per Second and Burst Size.
Allowed SYNs per Second | Defines the number of allowed SYN packets per second.
Burst Size | The number of allowed SYNs before the Engine starts limiting the SYN rate. We recommend that you set the burst size to be at least one tenth of the Allowed SYNs per Second value. If the burst size is too small, SYN rate limits do not work. For example, if the value for Allowed SYNs per Second is 10000, set the value for Burst Size to at least 1000.
Enable Log Compression | By default, each generated Antispoofing and Discard log entry is logged separately and displayed as a separate entry in the Logs view. Log Compression settings allow you to define the maximum number of separately logged entries. When the defined limit is reached, a single antispoofing log entry or Discard log entry is logged. The single entry contains information about the total number of the generated Antispoofing log entries or Discard log entries. After this log entry, the logging returns to normal and all generated entries are once more logged and displayed separately. Log Compression is useful when the routing configuration generates a large volume of antispoofing logs or the number of Discard logs becomes high. For each event type, Antispoofing or Discard, you can define: Log Rate (Entries/s) — The maximum number of entries per second. The default value for antispoofing entries is 100 entries/s. By default, Discard log entries are not compressed. Burst Size (Entries) — The maximum number of matching entries in a single burst. The default value for antispoofing entries is 1000 entries. By default, Discard log entries are not compressed.
Set to Default | Returns all changes to the log compression settings to the default settings.