A method and apparatus for testing network links bi-directionally and independently employ local test apparatus (1000) at one end of the link (1105, 1110, 1115) and remote test apparatus (1200) at the opposite end of the link. The local test apparatus transmits test traffic to the remote test apparatus which analyzes the test traffic to determine characteristics of the link in the local-to-remote direction. While the analysis is taking place, the remote test apparatus transmits interim test results to the local test apparatus, i.e., while the remote test apparatus is still running the test and without disrupting the test. Preferably, the remote test apparatus transmits test traffic to the local test apparatus which the latter analyzes to determine characteristics of the link in the remote-to-local direction. The local test apparatus may report the test results for both directions. The network may be a connected or connectionless network.