# Interface numbering

The interfaces have their own numbering in the SMC called the interface ID. The interface IDs are mapped to the corresponding network interfaces on the NGFW Engine when you configure the Forcepoint NGFW software.

Table 1. Interface numbering for NGFW Engines
Interface type | Interface numbering in the SMC
--- | ---
Layer 3 physical (Firewall/VPN role) | Each physical interface has a unique interface ID number.
Layer 2 physical (Firewall/VPN role)
Physical (IPS and Layer 2 Firewall roles)
VLAN | Each VLAN interface has a VLAN number. The defined VLAN interfaces are displayed, for example, as “5.202” for network interface 5 with VLAN 202.
ADSL | Each ADSL interface has a unique interface ID number. ADSL interfaces are only supported on legacy Forcepoint NGFW appliances.
Wireless | The wireless interface has a unique interface ID number. An SSID (service set identifier) interface represents an 802.11 wireless LAN. You can add several SSID interfaces to the wireless interface.
Modem | Modem Interfaces are identified with modem numbers. The modem number is mapped to the modem’s IMEI (international mobile equipment identity) number. Each modem is assigned a unique ID when you connect the modem to the engine. You can change the mapping between the modem’s IMEI number and the modem ID through the engine command line, if necessary.
Tunnel | Tunnel interfaces are numbered with tunnel interface ID numbers. The mapping of Tunnel Interfaces to physical network interfaces on the engine is done automatically by the engine operating system based on the routing configuration.
Integrated switch | Integrated switches are identified with switch IDs. Integrated switches have predefined switch IDs. For example, the switch ID is 0 on Forcepoint NGFW 110 appliances. You can add port group interfaces to switches. Port group interfaces are identified by port group IDs. The defined switches and port group interfaces are displayed, for example, as 0.1 for switch ID 0 with port group 1.