[c-nsp] Cisco IOS ping utility reports lower RTT than possible

[Martin T]

Hi Adam,

> So how should I interpret the above tcpdump output please?
Timestamp at the beginning of each line is simply a delta in
micro-second resolution between current and previous line. So first
tcpdump captured an ICMP "echo request" message, then 10201 µs later
it captured ICMP "echo reply" message, then 431 µs later it captured
next ICMP "echo request" and then 10165 µs later it captured reply for
seq 1, etc.


Octavio,

> Does it? If you are referring to the -ttt output than that is done by tcpdump.
Yes. Linux ping utility works the same way.

> Good experiment. Sorry to say that I don't know why the measurements are so inaccurate.
I was also surprised.


Martin