[e2e] SCTP TSN/SSN reset

Dave Hart davehart at gmail.com
Thu Mar 31 03:15:15 PDT 2011

On Thu, Mar 31, 2011 at 08:16 AM, Kacheong Poon wrote:
> On 03/31/11 03:06 PM, Dave Hart wrote:
>> On Thu, Mar 31, 2011 at 05:05 AM, Kacheong Poon wrote:
>>> I guess I should summarize the confusion (!) I created on
>>> this list by asking a wrong question.
>> It seems only appropriate given the "confusion" was created by your
>> attempt to deceive your audience and your failure to disclose the axe
>> you were grinding.
> I never tried to "deceive" anyone.  I merely posted a
> question without making an assertion.

Your original message and the great majority of the traffic carried
the subject line "TCP sequence number reset" and began with the text:

> Just want to get some opinion from the list members about an
> idea proposed in an IETF draft.  The equivalent idea when
> applied to TCP is sequence number reset.  The idea is that
> assuming an application can access TCP sequence number with
> each byte of data, an app is allowed to reset the TCP sequence
> number when it wants to.

The message failed to point to the draft in question, and in fact
failed to mention SCTP at all.  That omission may have been
well-intentioned from your perspective, from mine it was deceptive to
omit important relevant information.  I would expect you to have
recognized that the SCTP proposal is not equivalent to the TCP
straw-man proposal (because TCP's sequence number is used more
narrowly and is not available to applications) and refrained from
claiming it is.

> If you don't
> agree with my TCP analogy and think that it is incorrect,
> it is fine.  But it does not mean that I "deceive" you by
> making such an analogy.  I don't know what your intention
> is by saying that I "deceive" the folks on this list.

My intention is to facilitate open, honest communication and a mature
exchange of ideas, and to discourage intentional omission of relevant

> But I don't believe it is a justified accusation.  And
> I don't think this kind of statement is appropriate in
> this mailing list.

You may be right, if you interpret my claim that you "attempt to
deceive" as an ad-hominem attack.  I consider it a criticism of your
actions here, and not upon your person.

>>> Although IMHO the same comments apply well to SCTP, I cannot
>>> say for sure that folks who had commented think the same.
>> You really ought to give up defending your mistake and start over.
>> TCP is not capable of carrying multiple distinguished streams as part
>> of a single connection and so is not an appropriate analogy.  IMO
>> nothing said about the utility of resetting TCP sequence numbers
>> within an established connection can be directly applied to SCTP,
>> simply because SCTP uses transport sequence numbers as initial stream
>> sequence numbers, which use can not be modeled by a TCP analogy.  You
>> might as well be arguing that retractable landing gear on airplanes
>> are useless because your car has never once needed to retract its
>> gear.
> You have your opinion and I have my opinion.  It is fine
> that you don't agree with my opinion.  But it does not mean
> that I need to give up my opinion and agree with yours.

Believe it or not, that was friendly advice.  I have taken no position
on the SCTP sequence number proposal and am inclined to agree with
your belatedly-apparent position.

Dave Hart

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