Bug ID 949145: Improve TCP's response to partial ACKs during loss recovery

Last Modified: Jan 16, 2024

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

Known Affected Versions:
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, 11.6.5.2, 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, 12.1.4, 12.1.4.1, 12.1.5, 12.1.5.1, 12.1.5.2, 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, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 13.1.3.3, 13.1.3.4, 13.1.3.5, 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, 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, 16.0.0, 16.0.0.1, 16.0.1

Fixed In:
16.1.0, 16.0.1.1, 15.1.2, 14.1.3.1, 13.1.3.6, 12.1.5.3, 11.6.5.3

Opened: Sep 28, 2020

Severity: 3-Major

Symptoms

- A bursty retransmission occurs during TCP's loss recovery period.

Impact

The bursty retransmissions may lead to more data getting lost due to large amount of data being injected into the network.

Conditions

- TCP filter is used. - TCP stack is used instead of TCP4 stack (based on profile settings). - Packet loss occurs during the data transfer and TCP's loss recovery takes place.

Workaround

In versions prior to v16.0.0, use a TCP profile which selects the TCP4 stack instead of the TCP stack. There is no workaround for version 16.0.0.

Fix Information

Partial ACK handling during loss recovery is improved.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips