Traffic processing is the amount of network data a firewall or similar security control must inspect, normalize, log, and forward. In cloud firewalls, this often becomes a metered quantity: the more bytes or gigabytes that pass through the service, the more the bill can rise. Some products charge directly for processed traffic, while others bundle it into appliance sizing or subscription tiers.
It matters because security controls are only effective if teams can afford to use them at the right depth. Attackers may try to flood a firewall with benign-looking traffic to raise cost, exhaust capacity, or force defenders to relax inspection. On the defensive side, understanding traffic processing helps teams estimate spend, choose the right deployment size, and test peak and failover load before production traffic arrives. It is a practical link between security policy and infrastructure economics.