An interface is a software representation in NI-XNET of a single Ethernet connector on your PXIe-8520. When programming your PXIe-8520 with NI-XNET, the interface is the reference that NI-XNET uses to communicate with the external hardware connected to the interface.

With NI-XNET, each Ethernet interface name uses the syntax ENETn. n is a 1-indexed integer that identifies a specific interface within the scope of that communication protocol.

For example, for a two-port Ethernet module, the interface names are as follows:

  • ENET1
  • ENET2
Tip Though you can change the interface number n within NI configuration software, NI recommends allowing NI-XNET to select the number automatically. NI-XNET always starts at 1 and increments for each new interface found within each protocol. By keeping the assigned names, you can write all your applications to assume those same interface names. The interface numbers that NI-XNET assigns to a device are persistent for as long as the device exists in your system, even if you add new hardware.
The documentation for your product and the NI-XNET software might also use the term port to refer to a specific connector on an NI-XNET device.
  • Port—Physical connector on NI-XNET hardware
  • Interface—Logical software representation of a physical connector on NI-XNET hardware

    • The benefit of this separation is that you can use the interface name as an alias to any port so that your application does not have to change when your hardware configuration changes. For example, if you have a PXI chassis with a single Ethernet module, the Ethernet port labeled Port 1 is assigned as interface ENET1. Later, if you remove the module and install another, NI-XNET assigns interface ENET1 to the port of the new module. Although the physical port is in a different place, programs written to use ENET1 work with either hardware configuration without modification.