Re-ECN: Adding Accountability for Causing Congestion to TCP/IP
This document introduces a new protocol for explicit congestion notification (ECN), termed re-ECN, which can be deployed incrementally around unmodified routers. The protocol works by arranging an extended ECN field in each packet so that, as it crosses any interface in an internetwork, it will carry a truthful prediction of congestion on the remainder of its path. The purpose of this document is to specify the re-ECN protocol at the IP layer and to give guidelines on any consequent changes required to transport protocols. It includes the changes required to TCP both as an example and as a specification. It briefly gives examples of mechanisms that can use the protocol to ensure data sources respond correctly to congestion,and these are described more fully in a companion document [I-D.briscoe-tsvwg-re-ecn-tcp-motivation]. Authors' Statement: Status (to be removed by the RFC Editor) Although the re-ECN protocol is intended to make a simple but far- reaching change to the Internet architecture, the most immediate priority for the authors is to delay any move of the ECN nonce to Proposed Standard status. The argument for this position is developed in Appendix E. Changes from previous drafts (to be removed by the RFC Editor) Full diffs from all previous verisons (created using the rfcdiff tool) are available at <http://www.bobbriscoe.net/pubs.html#retcp> From -07 to -08 (current version): Minor changes and consistency checks. References updated. From -06 to -07: Major changes made following splitting this protocol document from the related motivations document [I-D.briscoe-tsvwg-re-ecn-tcp-motivation]. Significant re-ordering of remaining text. New terminology introduced for clarity. Minor editorial changes throughout.