Search RFCs

RFC Editor

File formats:

Status:

PROPOSED STANDARD

Authors:

B. Ver Steeg
A. Begen
T. Van Caenegem
Z. Vax

Stream:

IETF

Source:

avt (rai)

Cite this RFC:TXT  | XML  |  BibTeX

DOI:  https://doi.org/10.17487/RFC6285

Discuss this RFC: Send questions or comments to the mailing listavt@ietf.org

Other actions:Submit Errata  | Find IPR Disclosures from the IETF  | View History of RFC 6285

Abstract

When an RTP receiver joins a multicast session, it may need toacquire and parse certain Reference Information before it can processany data sent in the multicast session. Depending on the join time,length of the Reference Information repetition (or appearance)interval, size of the Reference Information, and the application andtransport properties, the time lag before an RTP receiver canusefully consume the multicast data, which we refer to as theAcquisition Delay, varies and can be large. This is an undesirablephenomenon for receivers that frequently switch among differentmulticast sessions, such as video broadcasts.

In this document, we describe a method using the existing RTP and RTPControl Protocol (RTCP) machinery that reduces the acquisition delay.In this method, an auxiliary unicast RTP session carrying theReference Information to the receiver precedes or accompanies themulticast stream. This unicast RTP flow can be transmitted at afaster than natural bitrate to further accelerate the acquisition.The motivating use case for this capability is multicast applicationsthat carry real-time compressed audio and video. However, thismethod can also be used in other types of multicast applicationswhere the acquisition delay is long enough to be a problem. [STANDARDS-TRACK]

For the definition ofStatus,seeRFC 2026.

For the definition ofStream, seeRFC 8729.