Abstract: Determining directionally differentiated latency in a network by use of master and slave test instruments to record latency measurements in their native time bases, and retrieving test instrument latency frame transmit/receive timestamps from the master and slave and converting them to the time base of one of the master or slave by use of the offset calculation, utilizing 3 bounce timestamp exchange, providing one-way latency measurement with resolution of less than 100 ?s, using internal clocks in the test instruments, without requirement of expensive external time base technology.