Bug ID 1068445: TCP duplicate acks are observed in speed tests for larger requests

Last Modified: Aug 23, 2022

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 14.1.5, 15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 16.0.0, 16.0.0.1, 16.0.1, 16.0.1.1, 16.0.1.2, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3

Fixed In:
17.0.0, 16.1.3.1, 15.1.6.1, 14.1.5.1

Opened: Dec 16, 2021
Severity: 3-Major

Symptoms

- A lot of TCP duplicate acks are observed in speed tests for larger requests

Impact

- Reduced throughput because of duplicate ACKs and retransmissions

Conditions

Below conditions are met - Large request - fastL4 profile with PVA acceleration set - Below sys db variables are enabled tm.tcpsegmentationoffload tm.tcplargereceiveoffload - Softpva is used

Workaround

Either one of the conditions - fastL4 profile with PVA acceleration set to NONE - Disable below sys db variables tm.tcpsegmentationoffload tm.tcplargereceiveoffload

Fix Information

None

Behavior Change