A router may be tested using a packet-based testing technique in which the test packets are generated by the router. In one implementation, a forwarding plane in a router may include a first component to process header information of packets to determine forwarding information, and a memory component to store payload data for the packets. A control plane of the router may generate test packets, insert the test packets into the forwarding plane, receive a second set of packets from the forwarding plane, analyze the second set of packets to determine whether the second set of packets correspond to the inserted plurality of test packets, and output, based on the analysis, test results, relating to the operation of the routing device.