# RSVP The Resource ReSerVation Protocol - RSVP - is a signalling mechanism used for network management of [packets](/glossary/p/packet). It uses a method where resources available to handle [Quality Of Service](/glossary/q/qos) traffic is broadcasted throughout the network. Listening devices reply with a RESV (Reserve) message containing a [flow specification](/glossary/f/flowspec) for the traffic. Devices on the route between sender and listener either accept the reservation and handle the flow, or send a reject message. Reservations can end normally or time out as needed.