Subject: Re: NewReno and the 2001 Revision

From: Sally Floyd <[email-masked]>
Date: Tue, 13 Oct 1998 16:10:11 PDT

> So, it seems to
>me that the appropriate approach is to outline the general
>principles that should guide the development of SACK-based
>algorithms, in order to prevent such algorithms from hurting the
>network and contributing to congestion collapse.  However, it seems
>less important to try to decide which SACK-based algorithm is the
>best and standardize it (at least at this time).

Actually, I would agree with this approach on a wide range of issues
regarding TCP implementations, not just about SACK algorithms.  I think
it is important to make sure that TCP implementations follow such basic
congestion control principles as slow-start, cutting the congestion
control window in half in response to a packet drop or in response to
Explicit Congestion Notification, etc.  I also think it is important to
list clear bugs such as those catalogued in the tcpimpl documents.
However, I don't know of any reason why TCP responses have to be
standardized in complete detail, even without considering SACK.  There
are a number of areas that it seems to me don't involve
interoperability, dangers of congestion collapse, dangers of
inexcuseably poor performance for the user, etc., and therefore could
perfectly safely be left to the discretion of the implementor.  I am
going to try to write something up making this position more clear...

- Sally