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> Chapter 15 - High Availability > HA and load balancing > Using NP4 or NP6 processors to offload load balancing

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Using NP4 or NP6 processors to offload load balancing

FortiGates that include NP4 and NP6 network processors can provide hardware acceleration for active-active HA cluster by offloading load balancing from the primary unit CPU. Network processors are especially useful when load balancing TCP and UDP sessions.

The first packet of every new session is received by the primary unit and the primary unit uses its load balancing schedule to select the cluster unit that will process the new session. This information is passed back to the network processor and all subsequent packets of the same sessions are offloaded to the network processor which sends the packet directly to a subordinate unit. Load balancing is effectively offloaded from the primary unit to the network processor resulting in a faster and more stable active-active cluster.

To take advantage of network processor load balancing acceleration, connect the cluster unit interfaces with network processors to the busiest networks. Connect non‑accelerated interfaces to less busy networks. No special FortiOS or HA configuration is required. Network processor acceleration of active-active HA load balancing is supported for any active‑active HA configuration or active-active HA load balancing schedule.