RSVP Use Cases
RSVP is a QoS mechanism that conforms to the IntServ QoS model. It was originally designed to be used purely for QoS purposes.
As a QoS mechanism, this might sound effective, but the problem is that it’s difficult to scale. Each router has to keep track of each reservation for each flow, and all routers within a topology must support RSVP.
For this reason, RSVP has fallen out of favor as far as QoS goes, and Differentiated Services, or DiffServ is now preferred. However, RSVP is still in use with MPLS Traffic Engineering.
Links
https://networklessons.com/quality-of-service/introduction-to-rsvp