Dynamic Feedback Protocol (DFP) is a protocol developed by Cisco Systems that allows servers to dynamically report their ability to provide services as well as changes in their status to a or .
See draft-eck-dfp-01 - Internet-Draft: Dynamic Feedback Protocol
An open source, BSD licensed, multiplatform reference implementation of DFP agent (i.e. server side) is available at http://dfp.berlios.de