Green telnet

The University of South Florida has designed a 'green telnet' that allows clients transition to a low-power, sleep state to save energy and not lose their telnet session (and state) in the server. The organization has modified telnetd to recognize when a client machine goes to sleep, gracefully handling the loss of the TCP connection, and then buffering data for the sleeping client. When the telnet client wakes up, a new TCP connection is established and the data buffered in the server is delivered to the client. The advanced 'gtelnetd' daemon is a modification of the Minix 3 telnetd daemon and is as distribution agnostic as possible by relying on fork() and minimal IPC primitives. Three processes also are used between the network connection and the telnetd application to enable the client machine to go to sleep without losing its session. These three processes coordinate data transfer, data queuing, and sleep/wake state transitions in a manner that is transparent to the telnet session.