RFC 9601: Propagating Explicit Congestion Notification across IP Tunnel Headers Separated by a Shim
In plain English — editorial summary, not part of the RFC
RFC 6040 on "Tunnelling of Explicit Congestion Notification" made the rules for propagation of Explicit Congestion Notification (ECN) consistent for all forms of IP-in-IP tunnel. This specification updates RFC 6040 to clarify that its scope includes tunnels where two IP headers are separated by at least one shim header that is not sufficient on its own for wide-area packet forwarding. It surveys widely deployed IP tunnelling protocols that use such shim headers and updates the specifications of those that do not mention ECN propagation (including RFCs 2661, 3931, 2784, 4380 and 7450, which specify L2TPv2, L2TPv3, Generic Routing Encapsulation (GRE), Teredo, and Automatic Multicast Tunneling (AMT), respectively). This specification also updates RFC 6040 with configuration requirements needed to make any legacy tunnel ingress safe.
Document record
- Document ID
- RFC9601
- Published
- August 2024
- Authors
- B. Briscoe
- Status
- PROPOSED STANDARD
- Stream
- IETF
- Area
- wit
- Pages
- 19
- Also known as
- —
Topics
Related documents
Ranked automatically by shared keywords, IETF area and stream — not by editorial selection.
- RFC 9599Guidelines for Adding Congestion Notification to Protocols that Encapsulate IPCurrent
August 2024
- RFC 9768More Accurate Explicit Congestion Notification (AccECN) Feedback in TCPCurrent
April 2026
- RFC 6660Encoding Three Pre-Congestion Notification (PCN) States in the IP Header Using a Single Diffserv Codepoint (DSCP)Current
July 2012
- RFC 9332Dual-Queue Coupled Active Queue Management (AQM) for Low Latency, Low Loss, and Scalable Throughput (L4S)Current
January 2023
- RFC 9331The Explicit Congestion Notification (ECN) Protocol for Low Latency, Low Loss, and Scalable Throughput (L4S)Current
January 2023
- RFC 9330Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: ArchitectureCurrent
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The document record above — title, authors, date, status, stream, area, relationships, DOI and errata — is imported verbatim from the public RFC Editor index. The “in plain English” section is editorial: written by The metasystema editorial team, not part of the RFC. Where the two differ, the RFC text governs.
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