Bug ID 674591: Packets with payload smaller than MSS are being marked to be TSOed

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
11.5.4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.1, 11.6.2, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2, 12.1.0, 12.1.1, 12.1.2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.2, 13.1.1.3, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1

Fixed In:
14.1.0, 13.1.1.4, 12.1.4, 11.6.5.2

Opened: Jul 18, 2017

Severity: 3-Major

Related Article: K37975308

Symptoms

Packets with length less than the specified MSS are sent as TSO packets, and the Broadcom NIC drops those to degrade performance.

Impact

TCP Packets are dropped.

Conditions

When TM.TcpSegmentationOffload is enabled, Packets with length less than MSS are sent as TSO packets.

Workaround

Disable TSO option by setting the following SYS DB variable to disable: TM.TcpSegmentationOffload.

Fix Information

Packets less than MSS are not sent as TSO packets, so there is no performance degradation.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips