RFC 6660: Encoding Three Pre-Congestion Notification (PCN) States in the IP Header Using a Single Diffserv Codepoint (DSCP)
In plain English — editorial summary, not part of the RFC
The objective of Pre-Congestion Notification (PCN) is to protect the quality 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 certain configured rates are exceeded. Egress nodes pass information about these PCN-marks to Decision Points that then decide whether to admit or block new flow requests or to terminate some already admitted flows during serious pre-congestion. This document specifies how PCN-marks are to be encoded into the IP header by reusing the Explicit Congestion Notification (ECN) codepoints within a PCN-domain. The PCN wire protocol for non-IP protocol headers will need to be defined elsewhere. Nonetheless, this document clarifies the PCN encoding for MPLS in an informational appendix. The encoding for IP provides for up to three different PCN marking 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 obsoletes RFC 5696. [STANDARDS-TRACK]
Document record
- Document ID
- RFC6660
- Published
- July 2012
- Authors
- B. Briscoe; T. Moncaster; M. Menth
- Status
- PROPOSED STANDARD
- Stream
- IETF
- Area
- tsv
- Pages
- 24
- Also known as
- —
- Obsoletes:
- RFC 5696
Topics
Related documents
Ranked automatically by shared keywords, IETF area and stream — not by editorial selection.
- RFC 7713Congestion Exposure (ConEx) Concepts, Abstract Mechanism, and RequirementsCurrent
December 2015
- RFC 5559Pre-Congestion Notification (PCN) ArchitectureCurrent
June 2009
- RFC 7141Byte and Packet Congestion NotificationCurrent
February 2014
- RFC 9601Propagating Explicit Congestion Notification across IP Tunnel Headers Separated by a ShimCurrent
August 2024
- RFC 7837IPv6 Destination Option for Congestion Exposure (ConEx)Current
May 2016
- RFC 2212Specification of Guaranteed Quality of ServiceCurrent
September 1997
- RFC 6040Tunnelling of Explicit Congestion NotificationUpdated
November 2010
- RFC 9330Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: ArchitectureCurrent
January 2023
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