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LBT (Load Based Teaming) explained (Part 3/3)

By Hugo Strydom, Management Consultant, VMware Professional Services

In this part we will look at some scenarios and what will happen when a pNIC is saturated.

Scenario 1:

ESX host with 2x 1Gb pNIC’s that is attached to a vDS . pNIC0 is above 75% threshold.

  • LBT will calculate to evaluate which vNIC traffic can be moved off pNIC0 to pNIC1
  • As part of the calculation LBT will also determine that if a vNIC is moved over to pNIC1 it will not saturate pNIC1


Scenario 2 :


ESX host with 3x 1Gb pNIC’s that is attached to a vDS. pNIC0 and pNIC1 is above the 75% threshold.

  • Only pNIC2 will be considered for traffic to be moved onto.


Scenario 3 :


ESX host with 2x 1Gb pNIC’s, 2 Port Groups, PG1 have been set to use LBT and PG2 have been set to use “Virtual Port ID”.

  • LBT will look at the total load on the pNIC and not just the load that the VM’s attached to PG2 have.
  • All VM’s that is attached on PG1 will not be moved to other pNIC’s, only the VM’s that is connected to PG2 (LTB Port Group) will be considered to be moved between pNIC’s.

Looking at Scenario 3 one should be careful not to configure or design vDS port groups on the same pNIC’s with different Port Group Load Balance policies. It could have a negative effect on performance and lead to overloading of load on pNIC’s.

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