What does ping timeout mean?

The network command 'ping' issues a series of standard, small messages to the destination network address specified by the user. For example:

ping 192.168.0.1

This command will send a number of 'ping' messages to the computer on the network with IP address 192.168.0.1

Upon receiving these messages, the destination machine will echo the same message back to the sender. This is used as a simple check of the network connectivity between the two computers on the network. Since an unreachable address will result in no message being returned, the sending machine must know how long to wait before considering the message lost. This time is known as the 'timeout'.

By default, it is 1000 millisecond (1 second) but it can be set to any time by the user with the '-w' option. For example:

ping -w 2000 192.168.0.1

This will cause the ping program to wait for two seconds before considering a ping packet lost.