Meaning – The term keepalive message, refers to the message sent among nodes when no data traffic has been detected for a given period of time. This communication ensures the vitality of the session by keeping the link alive. Sometimes, when we are on the network, there may be a period of time where there may not be any tasks or data exchange, but you be anticipating some activity later one and thus want the session active. The keepalive message helps keep it active.
A keepalive signal is often sent at predefined intervals and plays an important role on the Internet. After a signal is sent, if no reply is received the link is assumed to be down and future data will be routed via another path until the link is up again. A keepalive signal can also be used to indicate to Internet infrastructure that the connection should be preserved.
Example of usage – “Without a keepalive signal, intermediate NAT-enabled routers can drop the connection after a timeout.”