Bug ID 588569: Don't include maximum TCP options length in calculating MSS on ICMP PMTU.

Last Modified: Nov 07, 2022

Bug Tracker

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

Known Affected Versions:
11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 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, 11.5.10, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2, 11.6.0, 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, 11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 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, 11.6.5.3

Fixed In:
11.5.4 HF3

Opened: Apr 19, 2016
Severity: 4-Minor

Symptoms

TCP segment size is 40 bytes less.

Impact

The impact of this issue is less data per TCP segment.

Conditions

ICMP implementation using Path MTU (PMTU). User enables MPTCP, Rate Pacing, or any of the following congestion controls: Vegas, Illinois, Woodside, CHD, CHG

Workaround

Disable Path MTU Discovery by doing the following, "tmsh modify sys db tm.enforcepathmtu value disable"

Fix Information

Don't include maximum TCP options length in calculating MSS on ICMP PMTU in the advanced TCP implementation.

Behavior Change