AutoCAD network license and 'heartbeat'

If you want to know the meaning of the term "heartbeat", the below comes from the AutoCAD Knowledge Base. I was notified about it by the new RSS feeds.

Meaning of term "heartbeat" Published date: 2005-07-12 ID: TS66065 Applies to: AutoCAD® 2006 AutoCAD® 2005 AutoCAD® 2004 AutoCAD® 2002 Issue The term "heartbeat" is used in reference to a network license. You would like to know what this term means. Solution When AutoCAD is running, it communicates with the license server at one-minute intervals using a communication method known as the "heartbeat." If the heartbeat connection is missed, the server tries to reconnect. If it cannot, it sends a message to the user indicating a license error. Once the user acknowledges the message, AutoCAD starts a 6 minute countdown to give the user time to save his or her work. When AutoCAD stops working because it lost a connection to the server, you must shut down AutoCAD and restart the program. If the problem causing the original loss of the heartbeat signal is resolved, and there are available licenses on the server, the program starts working again. Note: If you are using the redundant server model, this server model also passes heartbeats between redundant servers.