The format of this file:
source dest ron send1_time rec1_time send2_time rec2_time

source:  The originator of the probe
dest:    The destination to which the probe was sent
ron:     0 = direct on the Internet
         1 = latency optimized
         2 = loss optimized RON path
send1_time:  The time immediately before sendto() on the source
rec1_time:   Time at which the packet was received on the interface
             at the destination
send2_time:  Time at which the packet was sent back to the sender by
             the destination
rec2_time:   Time at which the packet was received at source's interface

If the *_time entry is 0, it means the packet was lost before
being received.  No send_* entries should be null without the
previous rec_* entry being null.

The one-way latencies are not accurate;  the clocks on these machines
were only roughly synchronized.  Future datasets will aim to correct
this.