Regarding Latency In Ping

Question

What is meant by latency which is returned by ping?

i.e. the 'time' in the below

C:\Users\guest>ping -n 2 www.google.com

Pinging www.google.com [62.252.60.89] with 32 bytes of data: 
Reply from 62.252.60.89: bytes=32 time=11ms TTL=58 
Reply from 62.252.60.89: bytes=32 time=15ms TTL=58

Ping statistics for 62.252.60.89:
    Packets: Sent = 2, Received = 2, Lost = 0 (0% loss), 
Approximate round trip times in milli-seconds:
    Minimum = 11ms, Maximum = 15ms, Average = 13ms

Answer 1

It's the time (also known as 'round trip time') between sending the request and receiving the response. Typically this is only a few milliseconds for localhost or the local network but can be very large (relatively) for satellite transmissions, for example.

If it's likely to be more than one second, you may have to bump up the timeout so as to not detect it as a lost packet.

The following diagram shows you the idea.

    SENDER               RECEIVER
                  |    |
    ping request  |\   |
             ^    | \  |
             |    |  \ |
    latency -+    |   \| ping received
             |    |   /| ping response
             |    |  / |
             v    | /  |
    ping response |/   |
    received      |    |

Answer 2

Ping measures the round-trip delay, i.e. the time it takes for network packets to go from the sending hos A, to the destination host B, and back again.