Packet Flow Errors

Introduction

Application Note Number: AN-5501

Authors: John Smith and Jane Smith

Last Modified Date: 2016/04/15

Overview

Packet flow errors printed in console/terminal as upper-case letters:

Underrun on Tx (“U”): Samples not being produced by the host application fast enough. CPU governor or other power management not configured correctly.

Overrun on Rx (“O”): Samples not being consumed by the host application fast enough. CPU governor or other power management not configured correctly.

Sequence Error on Tx (“S”): Network hardware failure. Check host NIC, cable, switch, etc. Frame size might not work with the current NIC's MTU.

Dropped Packet on Rx (“D”): Network hardware failure. Check host NIC, cable, switch, etc. PCIe bus on host cannot sustain throughput. CPU governor or other power management not configured correctly. Frame size might not work with the current NIC's MTU. Check "ethtool -S <interface>".

Late Packet on Tx (“L”): Samples are not being produced by user's application fast enough. CPU governor or other power management not configured correctly. Incorrect/invalid time_spec provided. Usually on MIMO. http://files.ettus.com/manual/page_usrp_x3x0_config.html