Forwarding Equivalence Class (FEC)
A forwarding equivalence class is a group of packets that an MPLS network treats identically, sending them along the same path with the same priority and label.
What is Forwarding Equivalence Class (FEC)?
At the edge of an MPLS network, the ingress router classifies each packet into an FEC, for example by destination prefix or service class, and attaches the matching label. Every router along the path then forwards on the label alone. The label's 3-bit Traffic Class field (formerly EXP) carries its quality-of-service priority.