RSVP ReSerVation Protocol
Designed to handled multicast flows, where multiple receivers may have different capabilities
RSVP is receiver-initiated, i.e. receiver generates reservation
PATH message tentatively reserves resources, RESV makes reservation (travels as far back up as necessary)
RSVP supports merging of reservations
RSVP is decoupled from routing
PATH and RESV messages periodically sent to refresh state before timeout (i.e. soft state)
Multiple senders can share the same reservation
In contrast, ATM signaling (Q.2931) is sender-initiated, coupled with routing, uses hard state (i.e. explicit delete), and handles only uniform QoS