Green telnet is a modified telnet client/server that enables the client to go to sleep without breaking the telnet session by queuing data destined for the client while it is asleep.

The energy consumption of Internet edge devices, for example, desk top PCs is of growing concern. While much has been done to curtail the energy footprint of servers, the client is often ignored.
However, because of the large number of client computers in a system and the non-use of power management on these clients, the overall power consumption of the entire system is increased even if the server has been highly optimized.

Our Green Telnet aims to increase the usage of power management in client machines by allowing them to go to sleep, thus losing their connection to the server, but still have their sessions remain active. Once the client wakes back up, the connection is restored and the session continues as normal. Green Telnet accomplishes this by buffering any data destined for a sleeping client on the server, and then transmitting the buffered data to the client when it wakes back up.

Green Telnet is composed of two pieces: the gtelnetd daemon and the gtelnet client. gtelnetd is a modified port of the Minix 3 telnet daemon, itself a port of the original BSD telnet server. gtelnet is in turn a modified port of the Minix 3 telnet client.

This material is based upon work supported by the National Science Foundation under Grant No. 0520081.