Tunnelling of Explicit Congestion Notification

Metadata

Publisher: IETF
Doc Type: Standard
Pages: 35
Abstract: This document redefines how the explicit congestion notification (ECN) field of the IP header should be constructed on entry to and exit from any IP-in-IP tunnel. On encapsulation, it updates RFC 3168 to bring all IP-in-IP tunnels (v4 or v6) into line with RFC 4301 IPsec ECN processing. On decapsulation, it updates both RFC 3168 and RFC 4301 to add new behaviours for previously unused combinations of inner and outer headers. The new rules ensure the ECN field is correctly propagated across a tunnel whether it is used to signal one or two severity levels of congestion; whereas before, only one severity level was supported. Tunnel endpoints can be updated in any order without affecting pre-existing uses of the ECN field, thus ensuring backward compatibility. Nonetheless, operators wanting to support two severity levels (e.g., for pre-congestion notification -- PCN) can require compliance with this new specification. A thorough analysis of the reasoning for these changes and the implications is included. In the unlikely event that the new rules do not meet a specific need, RFC 4774 gives guidance on designing alternate ECN semantics, and this document extends that to include tunnelling issues. [STANDARDS-TRACK]
Publication Date: 2010-11-01
Status Note: Proposed Standard
DOI: 10.17487/RFC6040
Link: https://doi.org/10.17487/RFC6040
Author(s): Bob Briscoe
Keyword(s): Congestion Control, Congestion Notification, Information Security, Tunnel, Encapsulation, Decapsulation, Protocol, ECN, IPSEC

Latest version of IETF RFC 6040

Document Versions — IETF RFC 6040

▶ IETF RFC 6040 (2010-11-01)

THIS DOC [ACTIVE] [LATEST VERSION]

Amended by:

RFC9601 NOT IN REGISTRY

Normative Reference(s)

IETF RFC 2003 [Active*]
IETF RFC 2119 [Active*]
IETF RFC 3168 [Active*]
IETF RFC 4301 [Active, Amended*]

Bibliographic Reference(s)

10.1145-1080091.1080098 — VCP EXTERNAL
Briscoe, B., Moncaster, T., and M. Menth, "Encoding 3 PCN- States in the IP header using a single DSCP", Work in Progress, July 2010. EXTERNAL
IETF RFC 2401 [Superseded*]
IETF RFC 2474 [Active*]
IETF RFC 2481 [Superseded*]
IETF RFC 2983 [Active*]
IETF RFC 3540 [Active*]
IETF RFC 4774 [Active*]
IETF RFC 5129 [Active*]
IETF RFC 5559 [Active*]
IETF RFC 5659 [Active*]
IETF RFC 5670 [Active*]
IETF RFC 5696 [Superseded*]
IETF RFC 5996 [Superseded*]

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Referenced By

IETF RFC 8085 [Active*]