Bug ID 455553: ICMP PMTU handling causes multiple retransmissions

Last Modified: Sep 13, 2023

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

Known Affected Versions:
10.2.4, 11.0.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.5.1 HF1, 11.6.1 HF1, 11.5.1 HF2, 11.6.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.6.2 HF1, 11.1.0, 11.2.0, 11.2.1, 11.3.0, 11.4.0, 11.4.1

Fixed In:
11.6.0, 11.5.4 HF3, 11.5.1 HF5, 11.4.1 HF6, 11.2.1 HF15, 10.2.4 HF12

Opened: Apr 03, 2014

Severity: 3-Major

Related Article: K15714

Symptoms

When an improperly large TCP Maximum Segment Size (MSS) triggers ICMP PMTU messages, TCP responds by resending the entire send queue with the new MSS.

Impact

Large amounts of duplicate retransmission.

Conditions

This occurs when you configure a path with an MTU less than 1500 Bytes and attempt a file transfer with initcwnd greater than 1.

Workaround

None

Fix Information

No multiple retransmission of the entire send queue when the MSS size is improperly large.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips