Subject: [tsvwg] Fwd: I-D Action: draft-nielsen-tsvwg-sctp-tlr-02.txt

From: Karen Elisabeth Egede Nielsen <[email-masked]>
Date: Mon, 26 Oct 2015 13:49:34 +0100

Hi,

We recently uploaded a new version of the draft on improvements of SCTP
Tail Loss Recovery (SCTP TLR)
The approach follows the basic principle of having Loss Recovery of a data
chunk
be initiated once SACK of a later sent data chunk has arrived AND a
certain time > anticipated RTT  has elapsed.
If no SACKs have been seen when the time is up, the solution follows an
approach similar to TCP TLP by probing for SACK.

The solution is from an overall perspective similar to the TCP RACK/TCP
TLP approach for TCP.  At least in the outset.
At present the solution retains the legacy mis-indication counting
approach  (counting SACKs head of line)
and operates as a supplement (rather as a replacement)  to the legacy
approach.

The solution embeds RTO-restart principles and (delayed) Early
Retransmission for SCTP (RFC5827).
The solution, when supported,  exploit Immediate SACK, RFC7053, and
proposes a new unambiguous SACK format for SCTP, which allow for
optimization of the SCTP TLR operation.

We have implemented the functions and are presently performing test
experiments.
The results of which we will be happy to present and discuss if time
becomes available during the tsvwg session(s).

Please send any comments that you may have to the lists or directly to the
authors. Many thanks.

BR, Karen

________________________________________
A New Internet-Draft is available from the on-line Internet-Drafts
directories.

        Title           : SCTP Tail Loss Recovery Enhancements
        Authors         : Karen E. E. Nielsen
                          Rafaelle De Santis
                          Anna Brunstrom
                          Michael Tuexen
                          Randall Stewart
	Filename        : draft-nielsen-tsvwg-sctp-tlr-02.txt
	Pages           : 42
	Date            : 2015-10-19

Abstract:
   Loss Recovery by means of T3-Retransmission has significant
   detrimental impact on the delays experienced through an SCTP
   association.  The throughput achievable over an SCTP association also
   is negatively impacted by the occurrence of T3-Retransmissions.  The
   present SCTP Fast Recovery algorithms as specified by [RFC4960] are
   not able to adequately or timely recover losses in certain
   situations, thus resorting to loss recovery by lengthy
   T3-Retransimissions or by non-timely activation of Fast Recovery.  In
   this document we specify a number of enhancements to the SCTP Loss
   Recovery algorithms which amends some of these deficiencies with a
   particular focus on Loss Recovery for drops in Traffic Tails.  The
   enhancements supplement the existing algorithms of [RFC4960] with
   proactive probing and timer driven activation of the Fast
   Retransmission algorithm as well as a number of enhancements of the
   Fast Retransmission algorithm in itself are specified.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-nielsen-tsvwg-sctp-tlr/

There's also a htmlized version available at:
https://tools.ietf.org/html/draft-nielsen-tsvwg-sctp-tlr-02

A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-nielsen-tsvwg-sctp-tlr-02

Please note that it may take a couple of minutes from the time of
submission
until the htmlized version and diff are available at tools.ietf.org.

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/