Line Loopback

Feature Set N-ANL9

Napatech SmartNIC
Content Type
Feature Description
Capture Software Version

In this chapter

This chapter describes the line loopback functionality, which enables frames received on one network port to be retransmitted to the same network port without involving the host CPU.


Frames larger than 10,000 bytes are marked with an inverted FCS, that is a CRC error, by the accelerator retransmission functionality.

Frames are looped back without being modified. This includes the Ethernet CRC which is not recalculated.

The line loopback functionality and the filtering/capturing functionality can be used independently of each other. If the accelerator has been configured for line loopback, it can at the same time be set up to capture, for instance, all received IP frames.

Configuration interface

The line loopback functionality can be enabled by using the config tool or by using the NTAPI.