pfSense supports multiple methods of traffic shaping / Quality of Service (QoS). The two supported methods for configuring traffic shaping are ALTQ and Limiters, both of which are described in this section.
In either case, connections are classified based on matching firewall rules.
What is traffic Shaping?¶
Traffic shaping (also known as “packet shaping”) is the control of computer network traffic in order to optimize or guarantee performance, lower latency, and/or increase usable bandwidth by delaying packets that meet certain criteria. More specifically, traffic shaping is any action on a set of packets (often called a stream or a flow) which imposes additional delay on those packets such that they conform to some predetermined constraint (a contract or traffic profile).
—From the Wikipedia article on Traffic Shaping