What is the purpose of an echo message in networking?

The purpose of an echo message in networking is to send a ping for responsiveness confirmation. When an echo message is sent, typically as part of a ping command, it checks the communications path between two devices on a network. The echo request is sent from the initiating device to the target device, and if the target is reachable and operational, it responds with an echo reply. This exchange confirms that the target is not only present on the network but also reachable, thus allowing network administrators to diagnose issues and ensure that the network is functioning correctly. By measuring the round-trip time of the echo request and reply messages, it can also help in assessing the quality of the connection between the two devices.