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Status:

PROPOSED STANDARD

Obsoletes:

RFC 5696

Authors:

B. Briscoe
T. Moncaster
M. Menth

Stream:

IETF

Source:

pcn (tsv)

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DOI:  https://doi.org/10.17487/RFC6660

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Abstract

The objective of Pre-Congestion Notification (PCN) is to protect thequality of service (QoS) of inelastic flows within a Diffserv domain.The overall rate of PCN-traffic is metered on every link in the PCN-domain, and PCN-packets are appropriately marked when certainconfigured rates are exceeded. Egress nodes pass information aboutthese PCN-marks to Decision Points that then decide whether to admitor block new flow requests or to terminate some already admittedflows during serious pre-congestion.

This document specifies how PCN-marks are to be encoded into the IPheader by reusing the Explicit Congestion Notification (ECN)codepoints within a PCN-domain. The PCN wire protocol for non-IPprotocol headers will need to be defined elsewhere. Nonetheless,this document clarifies the PCN encoding for MPLS in an informationalappendix. The encoding for IP provides for up to three different PCNmarking states using a single Diffserv codepoint (DSCP): not-marked(NM), threshold-marked (ThM), and excess-traffic-marked (ETM).Hence, it is called the 3-in-1 PCN encoding. This document obsoletesRFC 5696. [STANDARDS-TRACK]

For the definition ofStatus,seeRFC 2026.

For the definition ofStream, seeRFC 8729.