I found the missing 30 milliseconds!

Everyone; You can't send a packet out an interface until the entire packet has been received on the incoming interface. Now if we assume 1500 byte packets (the new de facto MTU on all modern Internet backbones) and DS-3 pipes, then it takes about 250 microseconds to buffer the pkt on each hop. Since the US internet backbone from coast to coast is about 120 hops, there's your 30 milliseconds and Bob's your uncle. Did I do the arithmetic right? --Kent, ever helpful with NANOG metrication ;-) Well, back when us old guys were young, switching delay *was* significant. Did I ever show you my p4200?