Bug ID 447874: TCP zero window suspends data transfer

Last Modified: Apr 28, 2025

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

Known Affected Versions:
11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.1 HF10, 11.5.1 HF11, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5

Fixed In:
12.0.0, 11.6.0 HF6, 11.5.2, 11.4.1 HF9

Opened: Feb 07, 2014

Severity: 3-Major

Related Article: K16422

Symptoms

HTTP pipeline request might cause TCP window stay at 0 and not recover.

Impact

When this occurs, the resulting TCP zero window suspends data transfer. It is possible that the TCP window will be reduced to 0 (zero) and never recover.

Conditions

This intermittent issue occurs when HTTP pipeline requests are sent, and those requests use the GET method.

Workaround

None.

Fix Information

HTTP pipeline request no longer causes TCP window stay at 0 when HTTP pipeline requests are sent, and those requests use the GET method.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips