This document specifies the Resource Reservation Protocol (RSVP), a standards track protocol for the Internet community. It provides receiver-initiated setup of resource reservations for multicast or unicast data flows, with good scaling and robustness properties. The protocol is designed for an integrated services Internet, where it can be used by hosts to request specific qualities of service from the network for particular application data streams or flows. RSVP operates on top of IPv4 or IPv6, occupying the place of a transport protocol in the protocol stack. It is not a routing protocol but operates with current and future unicast and multicast routing protocols. RSVP makes receivers responsible for requesting specific QoS, which are then passed to all nodes along the data path. The protocol supports various reservation styles, including Wildcard-Filter (WF), Fixed-Filter (FF), and Shared-Explicit (SE). RSVP uses a "soft state" approach to manage reservation state, with periodic refresh messages to maintain state and teardown messages to remove it. The document also covers error handling, confirmation mechanisms, policy control, security considerations, and non-RSVP cloud support.This document specifies the Resource Reservation Protocol (RSVP), a standards track protocol for the Internet community. It provides receiver-initiated setup of resource reservations for multicast or unicast data flows, with good scaling and robustness properties. The protocol is designed for an integrated services Internet, where it can be used by hosts to request specific qualities of service from the network for particular application data streams or flows. RSVP operates on top of IPv4 or IPv6, occupying the place of a transport protocol in the protocol stack. It is not a routing protocol but operates with current and future unicast and multicast routing protocols. RSVP makes receivers responsible for requesting specific QoS, which are then passed to all nodes along the data path. The protocol supports various reservation styles, including Wildcard-Filter (WF), Fixed-Filter (FF), and Shared-Explicit (SE). RSVP uses a "soft state" approach to manage reservation state, with periodic refresh messages to maintain state and teardown messages to remove it. The document also covers error handling, confirmation mechanisms, policy control, security considerations, and non-RSVP cloud support.