Bug ID 639516: Improve traffic distribution on backplane links

Last Modified: Nov 07, 2022

Bug Tracker

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

Known Affected Versions:
12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3,,,,,,,, 12.1.4,, 12.1.5,,,, 12.1.6, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1

Fixed In:

Opened: Jan 16, 2017
Severity: 4-Minor


For chassis based platforms such as 2400 and 4800, there is a primary link and a secondary link from a blade to every other blade in the chassis. Both hidden links form a trunk. Sometimes the traffic is not divided between both links in a uniform way.


One link may be quite busy, while the other link is relatively idle.


The exact condition under which this occurs is not well defined, but depends on the traffic.



Fix Information

The fix improves the hashing algorithm such that traffic is distributed between both links in a more uniform way.

Behavior Change