QoS Resource Reservation Protocol (RSVP)
Resource Reservation Protocol (RSVP) is a QoS protocol used to reserve resources to achieve a specific level of QoS. Bandwidth resources are reserved from end to end before communication takes place between two hosts. Once the communication is complete, the resources are released. RSVP conforms to the IntServ QoS model.
Resource reservation signals the network and requests a certain bandwidth and delay that is required for a flow. When the reservation is successful each network component (mostly routers) will reserve the bandwidth and delay that is required. Admission control is used to permit or deny a certain reservation.
Links:
https://networklessons.com/quality-of-service/introduction-to-rsvp