What Is RSVP?

Date First Published: 7th March 2022

Topic: Computer Networking

Subtopic: Internet Protocols

Article Type: Computer Terms & Definitions

Difficulty Level: 10/10

Learn more about what RSVP is in this article.

Short for resource reservation protocol, RSVP is a transport layer protocol used for reserving network resources in order to get different quality of services (QoS). RSVP functions over IPv4 or IPv6 and performs resource reservations from the receiver’s end. RSVP defines how reservations are placed by applications and how the resources can be dropped once no longer needed.

RSVP is a signalling protocol that focuses on the receiver. The receiver is the one who starts and keeps the resource reserve going. It's used for both unicasting (sending data from a single source to a single destination) and multicasting (sending data to a group of destination computers at the same time). RSVP enables dynamic network changes to be automatically adjusted and offers a variety of reservation options. In addition, it enables the development of more styles later.

RSVP was developed in 2003 to RSVP-TE for the purpose of teletraffic engineering. RSVP itself is rarely used in telecommunications networks. A suggested replacement for RSVP was NSIS (Next Steps In Signalling).

Types Of RSVP Messages

• Reservation Messages - The receiver sends the reservation message to the sender along the reverse path of the path message, indicating the resources that the data flow requires.
• Path Messages - The sender sends a path message to all receivers using multicasting, storing the path state at each node along the path. The information needed for the receivers to make the reservation is stored.