[tcpm] Protocol Action: 'The RACK-TLP loss detection algorithm for TCP' to Proposed Standard (draft-ietf-tcpm-rack-15.txt)

The IESG <iesg-secretary@ietf.org> Tue, 22 December 2020 18:31 UTC

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Date: Tue, 22 Dec 2020 10:31:39 -0800
Archived-At: <https://mailarchive.ietf.org/arch/msg/tcpm/fkeVrU1mBoR_OpSBZhZ3U_aLTCs>
Subject: [tcpm] Protocol Action: 'The RACK-TLP loss detection algorithm for TCP' to Proposed Standard (draft-ietf-tcpm-rack-15.txt)

The IESG has approved the following document:
- 'The RACK-TLP loss detection algorithm for TCP'
(draft-ietf-tcpm-rack-15.txt) as Proposed Standard

This document is the product of the TCP Maintenance and Minor Extensions
Working Group.

The IESG contact persons are Martin Duke and Magnus Westerlund.

A URL of this Internet Draft is:
https://datatracker.ietf.org/doc/draft-ietf-tcpm-rack/

Technical Summary

This document presents the RACK-TLP loss detection algorithm for TCP.
RACK-TLP uses per-segment transmit timestamps and selective
acknowledgements (SACK) and has two parts: RACK ("Recent
ACKnowledgment") starts fast recovery quickly using time-based
inferences derived from ACK feedback. TLP ("Tail Loss Probe")
leverages RACK and sends a probe packet to trigger ACK feedback to
avoid retransmission timeout (RTO) events. Compared to the widely
used DUPACK threshold approach, RACK-TLP detects losses more
efficiently when there are application-limited flights of data, lost
retransmissions, or data packet reordering events. It is intended to
be an alternative to the DUPACK threshold approach.

Working Group Summary

The general approach was uncontroversial. As the algorithm is quite
intricate, there were many comments to clarify the text and the
pseudocode.

Document Quality

The core mechanisms described in the document are implemented in FreeBSD, Linux, and Windows. They are in active use on these platforms. RACK can also be used by other transport protocols. QUIC loss recovery uses the same ideas and there exists also an implementation for SCTP within a simulation environment.

Personnel

The document shepherd is Michael Tüxen. The Responsible AD is Martin Duke

[tcpm] Protocol Action: 'The RACK-TLP loss detect… The IESG