HI, Thanks a lot.
Please find inline below. Nothing outstanding as far as I can tell :-) BR, Karen > -----Original Message----- > From: Brian Trammell [mailto:i...@trammell.ch] > Sent: 12. november 2015 15:47 > To: Karen Elisabeth Egede Nielsen <karen.niel...@tieto.com> > Cc: taps@ietf.org; Mirja Kühlewind <mirja.kuehlew...@tik.ee.ethz.ch>; > Michael Tuexen <tue...@fh-muenster.de> > Subject: Re: [Taps] I-D Action: draft-ietf-taps-transports-07.txt > > hi Karen, > > Thanks for the comments and review! Commentcomments inline, anything > not remarked on is accepted into -08 as-is. > > > On 28 Oct 2015, at 13:16, Karen Elisabeth Egede Nielsen > <karen.niel...@tieto.com> wrote: > > > > HI, > > > > Please accept the following comments. > > Use them as/if you see fit. > > (Given my wretched, non-twistable, arms you are allowed not to take > > them too seriously) > > > > Section 3.1.1: > > > > 6'th paragraph: > > > > " In addition, a congestion control > > mechanism may react to changes in delay as an early indication for > > congestion." > > > > I think one will need to give a reference to this as it is not covered > > by the reference to RFC5681. > > Possibly this statement is better given in the context of the next > > paragraph referring to extensions. > > > > [I am aware that I have given this comment before. The reason that > > this continues to be an issue for me is that delay based CC alg's also > > are applicable to, e.g., SCTP (and have been applied there, though I > > don't know much about real deployment of them for SCTP). > > I am not sure if the solution to this is to have a special common > > section about congestion control algorithms - referring possibly to > > that these special CC als mostly are in deployment for TCP]. > > It does seem to me that CC algorithms as deployed in the Internet are > somewhat orthogonal to the mechanics of the underyling transport protocol, > so this is probably not a bad idea... I'll have a look at how this could > be easily > refactored out of the document, probably into a new section 4 (before the > present section 4)... > [Karen Elisabeth Egede Nielsen] This would be great, _I_ think. > > 9'th paragraph: > > > > Reference to push flag: > > > > The sentence: > > > > "TCP provides a push and a urgent function to enable data to be > > directly accessed by the receiver without having to wait for in-order > > delivery of the data." > > > > Should be revised I think. It is not very clear what the push flag > > contribute with in this sentence. The PUSH flag helps to release a > > "tail" > > packet from a TSO/GRO function/temporary packet buffering function. > > This feature of TCP might be significantly enough to describe the PUSH > > flag function as an implicit and internal protocol implementation > > optimization making TCP "push" tails through intermediate buffering > > functions. But the PUSH function is not really a "function" that TCP > > stacks provide to the ULP today (even if this is described as an > > optional possibility in RFC1122) - Or is it ? > > I've never seen it treated as one; to my knowledge inconsistent treatment > has led to PSH being largely ignored/ignorable, but there are probably > people > with more thorough knowledge on this list... > [Karen Elisabeth Egede Nielsen] Yes. Unfortunately we have had outtages (killing services in regions - not a small issue..) recently as some applications had put trust into the PUSH bit. That's why I would not like the document to point to this as valid service provided by TCP to ULP. Except for what I wrote above. > > The urgent flag is not recommended ... so does it belong here ? > > It does provide a (not very functional) out of order delivery mechanism, > though its deprecation should be referenced here here. Will do so in -08. > [Karen Elisabeth Egede Nielsen] super. > > Section 4.1: > > Section 4.1 has been removed, in the interests of getting the document out > the door. The hierarchical list in Section 4 replaces it. > > > I wonder if SCTP Reliability could be Full/Partial/None > > This is captured in the present (GitHub) revision of the list. [Karen Elisabeth Egede Nielsen] ok thanks. > > > I wonder if unordered delivery should be added as a row. > > Unordered delivery is an entry in the list. > > > I am not sure if ECN for SCTP should be marked as TBD. Applicability > > of > > RFC3168 to SCTP is described in RFC4960. > > We don't have a line item for ECN in the list yet, perhaps we should. > > > I personally don’t know of any deployment of this. > > > By "no deployment" you mean "no implementation" or "it's not turned on"? [Karen Elisabeth Egede Nielsen] It is not turned on. One of the Ericsson SCTP SW bases (there are two) implements the feature following the "traditional" approach of RFC3168/RFC4960. This is the SCTP SW base with the largest deployment base/footprint. But we don't know of anywhere were it is active. Likely in many nodes the feature has not even made it to the O&M api. I.e., the applications has chosen not to expose the feature to the operators even if it _is_ exposed at SCTP API. Hopefully this will change. [A different issue of course is that the ECN in itself may change] > > Thanks again, cheers, > > Brian _______________________________________________ Taps mailing list Taps@ietf.org https://www.ietf.org/mailman/listinfo/taps
