Subject: Architectural Issues

From: Carl-Uno Manros <[email-masked]>
Date: Mon, 6 Jul 1998 14:04:05 PDT

Dear Members of the IESG,

In recent discussions with Keith Moore in his role as Applications Area
Director, a couple of rather fundamental questions about Internet protocol
architecture have come up. As chair of one of the Application Area WGs, I
have had some difficulty to understand the current policy within the IESG
and the IAB on the following two aspects, and might have given my WG wrong
advice on the acceptability of certain technical solutions vs. others from
an IESG/IAB perspective. 

Issue 1 - Firewalls
===================

Although I have been unable to find much said about firewalls in the IETF
RFCs (RFC1579 and RFC2356 are the only references that come up), there
seems to be some undocumented views within the IESG about what is
appropriate and what is not when it comes to distinguishing different
applications in firewalls. If such criteria are indeed used by the IESG, I
think it is urgently needed to document them. They should distinguish
between outgoing vs. incoming firewalls and should clearly state on which,
and how many  "parameters", filtering must be possible (such as TCP/IP
address, scheme, port, method, content-type).

Issue 2 - Layering of Applications
==================================

It has also been discussed whether layering one application on another is
allowed, and if so, which kind of things can be layered on what, and which
combinations would be disallowed. This has resulted in debates such as if
HTTP is specific to web traffic or a more generic transport protocol. I
think it is particularly important to answer this question in anticipation
of the HTTP-NG protocol, which is planned for introduction in the IETF
later this year. To my knowledge, the designers of that protocol have
explicitly wanted to make a protocol that is a more genereric than the
current HTTP. Would that be in conflict with the IESGs ideas about what is
allowed or not over that protocol?  Again, any criteria that the IESG will
be using for this kind of layering decisions should be clearly documented,
so the WGs have a reasonable chance to stay within the boundaries of what
the IESG considers to be "correct" design.

Thankful for your feedback on this,

Carl-Uno Manros
Chair of IETF WG on IPP

Carl-Uno Manros
Principal Engineer - Advanced Printing Standards - Xerox Corporation
701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
Phone +1-310-333 8273, Fax +1-310-333 5514
Email: [email-masked]