Configuring ISF load balancing

On the FortiGate 1800F, 2600F, 3500F, 4200F, and 4400F you can use the following command to change the load balancing algorithm used by the ISF to distribute traffic received by a physical interface or a LAG to the NP7 processors in your FortiGate.

config system interface

edit <interface-name>

set sw-algorithm {l2 | l3 | eh | default}

end

On the FortiGate 1800F, 2600F, 3500F, 4200F, and 4400F you can combine the ISF load balancing configuration with NPU port mapping. Use NPU port mapping to send traffic received by a physical interface or a LAG to a group of NP7 processors or NP7 processor links. Then use ISF load balancing to control how that traffic is distributed among the configured group of NP7 processors or NP7 processor links. For information about FortiGate 1800F, 2600F, 3500F, 4200F, and 4400F NPU port mapping, see config system npu-post.

<interface-name> can be a physical interface or a LAG.

l2 use the layer 2 address for traffic distribution.

l3 use the layer 3 address for traffic distribution.

eh use enhanced hashing for traffic distribution.

default (the default) use the default traffic distribution algorithm selected for the ISF when the system starts up.

You can configure ISF load balancing for a single interface. If you add multiple interfaces to a LAG, you can use sw-algorithm to configure ISF load balancing for the LAG. The LAG sw-algorithm setting overrides the sw-algorithm setting of the individual interfaces in the LAG.