1. A test traffic generation and statistics collection system that transmits MPLS labeled packets through a device under test (abbreviated DUT) and receives the MPLS labeled packets after they pass through the DUT, including: a device that implements a first network of emulated devices and a second network of emulated devices, the device including a plurality of encapsulated protocol stacks that represent the first network of emulated devices and the second network of emulated devices, wherein some of the encapsulated protocol stacks dynamically apply MPLS labels to packets as the packets pass from one encapsulated protocol stack to another; the device further includes: a test packet generator that generates packets with destination IP addresses subject to forward equivalence class (abbreviated FEC) classification; a MPLS binder that applies FEC classification to dynamically assign equivalence classes to the packets received from the test packet generator, and adding MPLS labels to the packets, taking into account the destination IP addresses and the assigned equivalence classes; a connection to a physical transmit port that transmits the packets with the added routing labels to the DUT; the device further includes a packet receiver, coupled to a physical receive port, that receives packets that passed through the DUT, that counts packet statistics and that collects the packet statistics for analysis.