The IESG has received a request from the TCP Maintenance and Minor Extensions WG (tcpm) to consider the following document: - 'More Accurate Explicit Congestion Notification (ECN) Feedback in TCP' <draft-ietf-tcpm-accurate-ecn-31.txt> as Proposed Standard
The IESG plans to make a decision in the next few weeks, and solicits final comments on this action. Please send substantive comments to the [email protected] mailing lists by 2025-02-10. Exceptionally, comments may be sent to [email protected] instead. In either case, please retain the beginning of the Subject line to allow automated sorting. Abstract Explicit Congestion Notification (ECN) is a mechanism where network nodes can mark IP packets instead of dropping them to indicate incipient congestion to the endpoints. Receivers with an ECN-capable transport protocol feed back this information to the sender. ECN was originally specified for TCP in such a way that only one feedback signal can be transmitted per Round-Trip Time (RTT). Recent new TCP mechanisms like Congestion Exposure (ConEx), Data Center TCP (DCTCP) or Low Latency, Low Loss, and Scalable Throughput (L4S) need more accurate ECN feedback information whenever more than one marking is received in one RTT. This document updates the original ECN specification in RFC 3168 to specify a scheme that provides more than one feedback signal per RTT in the TCP header. Given TCP header space is scarce, it allocates a reserved header bit previously assigned to the ECN-Nonce. It also overloads the two existing ECN flags in the TCP header. The resulting extra space is exploited to feed back the IP-ECN field received during the 3-way handshake as well. Supplementary feedback information can optionally be provided in two new TCP option alternatives, which are never used on the TCP SYN. The document also specifies the treatment of this updated TCP wire protocol by middleboxes. The file can be obtained via https://datatracker.ietf.org/doc/draft-ietf-tcpm-accurate-ecn/ The following IPR Declarations may be related to this I-D: https://datatracker.ietf.org/ipr/1881/ _______________________________________________ IETF-Announce mailing list -- [email protected] To unsubscribe send an email to [email protected]
