Now, something to point out in the ICMP message, NPM is inserting data, so the NPM server 10.1
100.100 is sending an echo request, but is including data in the message.
NPM does this by default
and one of the reasons for doing this is that some devices between your NMS and the device that
you're pinging may block ICMP packets with certain criteria in the data fields.
Some firewalls, as an example, may block packets with a zero size data field, and some firewalls
will block packets with large payloads.
Some devices even block ICMP packets that are even or odd in size.
In this capture, we can see that the response packet was sent from router 2 to the NMS.
So it's an ICMP echo reply message and the NMS will calculate the difference between the time that
the request was sent and the reply received,
and it uses that to calculate the round trip, response time or latency of the network.