NP6 processors can offload sessions received by interfaces in link aggregation (LAG) groups. You can use link aggregation groups to offload more traffic that would exceed the capacity of a single FortiGate interface. For example, if you want to offload sessions on a 30 GB link you can add three 10-GB interfaces to a LAG group and send 30 GB of traffic to the LAG group.

Just like with normal interfaces, traffic accepted by a LAG group is offloaded by the NP6 processor connected to the interfaces in the LAG group that receive the traffic to be offloaded. If all interfaces in a LAG group are connected to the same NP6 processor, traffic received by the LAG group is offloaded by that NP6 processor. The amount of traffic that can be offloaded is limited by the capacity of the NP6 processor.

LAG groups can include interfaces connected to more than one NP6 processor. For example, a adding a second NP6 processor to a LAG group effectively doubles the offloading capacity of the LAG group. Adding a third further increases capacity. Using LAG groups allows you to increase offloading capacity for incoming traffic by sharing the traffic load across multiple NP6 processors. This increase in capacity is supported by the integrated switch fabric that allows the NP6 processors to share session information.

The increase in offloading capacity may not actually be doubled by adding a second NP6 processor to a LAG group. Traffic and load conditions and other factors may limit the actual achieved offloading result.