I believe that change was in the Nits provided by Alex already (and I forgot to apply before re-posting the draft);
The other issue mentioned by Alex, the failing PAWS test when ACKs get reordered (and the timestamp clock granularity is fine enough to have almost "individual" timestamps per data packet), is still something that I would like to work out.
But I need to dig into this some more (if this can be addressed in a efficient way), before I can post some meaningful updates to that aspect.
IMHO, making timestamps resilient in the face of fast timestamp clocks and/or high ACK reordering would be good properties to allow future extensions. But I would like to learn if this is just a minority opinion in this WG...
To quote you:
> Also, for this issue that Alexander brings up, the
> timestamp has to be changing between ACKs. If the
> timestamp hasn't changed between the re- ordered
> ACKs, then the "SEG.TSval >= TS.recent" check will
> succeed. Generally, the TS clock shouldn't be
> ticking that often, if it is changing with every
> ACK then it might be going faster than it needs to.
> So, this issue only occurs when ACKs are re-ordered,
> *and* the Timestamp clock has ticked between the
> reordered ACKs. I'm thinking that 1323bis should
> just note that this situation does exist.
> What does everyone else think? Shall we leave the
> text as is and just document this edge case, or do
> people disagree with me and feel that this is a
> real problem that needs to be addressed, and is
> more important than the problems that the original
> change fixes?
Gebäude G, Stiege 7, 3.OG
Am Euro Platz 2
> -----Original Message-----
> From: David Borman [mailto:dab@...]
> Sent: Freitag, 18. Mai 2012 19:38
> To: Scheffenegger, Richard
> Cc: tcpm@... Extensions WG
> Subject: Re: [tcpm] I-D Action: draft-ietf-tcpm-1323bis-02.txt
> Hi Richard,
> Thanks for doing the legwork on bringing this document into the modern
> age, the original nroff code was getting a bit old. :-)
> The pseudo code needs to be updated to match the main body of the
> document. Specifically, it has:
> Check whether the segment contains a Timestamps option and
> bit Snd.TS.OK is on. If so:
> If SEG.TSval < TS.Recent and the RST bit is off, then
> test whether connection has been idle less than 24 days;
> if all are true, then the segment is not acceptable;
> follow steps below for an unacceptable segment.
> If SEG.SEQ is equal to Last.ACK.sent, then save SEG.TSval
> in variable TS.Recent.
> There are four cases for the acceptability test for an
> incoming segment:
> The second case needs to be changed to:
> If SEG.SEQ is less than or equal to Last.ACK.sent, then save SEG.TSval
> in variable TS.Recent.
> -David Borman
> On May 18, 2012, at 11:14 AM, Internet-Drafts@... wrote:
> > A New Internet-Draft is available from the on-line Internet-Drafts
> directories. This draft is a work item of the TCP Maintenance and Minor
> Extensions Working Group of the IETF.
> > Title : TCP Extensions for High Performance
> > Author(s) : David Borman
> > Bob Braden
> > Van Jacobson
> > Richard Scheffenegger
> > Filename : draft-ietf-tcpm-1323bis-02.txt
> > Pages : 45
> > Date : 2012-05-18
> > This memo presents a set of TCP extensions to improve performance
> > over large bandwidth*delay product paths and to provide reliable
> > operation over very high-speed paths. It defines TCP options for
> > scaled windows and timestamps, which are designed to provide
> > compatible interworking with TCP's that do not implement the
> > extensions. The timestamps are used for two distinct mechanisms:
> > RTTM (Round Trip Time Measurement) and PAWS (Protection Against
> > Wrapped Sequences). Selective acknowledgments are not included in
> > this memo.
> > This memo updates and obsoletes RFC 1323.
> > A URL for this Internet-Draft is:
> > http://www.ietf.org/internet-drafts/draft-ietf-tcpm-1323bis-02.txt > >
> > Internet-Drafts are also available by anonymous FTP at:
> > ftp://ftp.ietf.org/internet-drafts/
> > This Internet-Draft can be retrieved at:
> > ftp://ftp.ietf.org/internet-drafts/draft-ietf-tcpm-1323bis-02.txt
> > The IETF datatracker page for this Internet-Draft is:
> > https://datatracker.ietf.org/doc/draft-ietf-tcpm-1323bis/ > >
> > _______________________________________________
> > tcpm mailing list
> > tcpm@... > > https://www.ietf.org/mailman/listinfo/tcpm