Nanosecond DUT Latency Testing with Hardware Timestamping
I wanted to measure how much latency a network device adds to a path, precisely enough to characterize a DUT (Device Under Test) that adds less than a microsecond. The instrument is a quad-port Intel i350, which does per-packet hardware timestamping and exposes a PTP hardware clock per port. The DUTs: a Netgear FE104 repeater hub, a Netgear FS105 10/100 switch, and a Netgear GS305 gigabit switch. Results up front: ...