asymentric Load-Balancing LACP

Unanswered Question
Feb 18th, 2009


we have a problem with a asymetric load-balancing in a LACP link. We have a switch-down (2970) with a LACP link formed by ports 16, 17, 6 and 7. In the switch-up the same LACP link is formed by 16, 17, 18 and 19. The ports are wired:

sw-down GE0/16<->sw-up GE0/16,

sw-down GE0/17<->sw-up GE0/17,

sw-down GE0/6<->sw-up GE0/18,

sw-down GE0/7<->sw-up GE0/19,

The issue is that traffic that going to switch-down port 6, go back through switch-up port 19, instead port 18. This is a problem because in each link there is a linux machine that filter the web traffic (pornographics access, etc...). Now the machines in links 6-18 and 7-19 have problems because asymetric traffic.

Are there any way to force a match between Ports by configuration?.


I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Yudong Wu Wed, 02/18/2009 - 10:33

I don't think we can control that. All 4 links act as one logical link.

Switch distributes the traffic load on all links based on certain hash algorithm. You can only control the input parameter to this hash algorithm such as source and/or destination mac.


This Discussion