Subject: [seamoby] IETF Architecture Work (RANT)

From: "Phil Neumiller" <[email-masked]>
Date: Wed, 11 Apr 2001 15:15:36 -0500

// BEGIN RANT

I am sending this rant to SeaMoby since I think its important to the
whole WG.  I am basing this off some threads I have seen go astray
due to a lack of a common set of terminology and assumptions (i.e.
stuff that can often be provided by an architecture).

I think when the IETF was young it was probably like working for a
startup.  You can't tolerate people that aren't good so they are immediately
gotten moved off the critical path and you keep the top talent that buys into
a common vision going.  In these situations, architecture is done implicitly,
its almost a Zen thing.

Today, we have a different IETF with lots of different visions, interests,
and time frames.  There are only a few people that can catch the "gestalt" of
an entire WG let alone multiple WGs and other SDOs that are coming
into the IETF to "influence" it.   If there was EVER a time for the IETF
to sincerely start documentings is architecture work (which it is doing a
lot of these days under the covers) it is now.

More comments below:

----- Original Message ----- >  >

>    The IETF has been well served by steering clear
>    of architectures. That isn't to say that lots
>    of people don't have architectures in mind when
>    they do protocol design; I'm sure most do.
>    However, I think there's a lot of merit to
>    leaving the architecture ambiguous because:

I think there is a subtle difference between ambiguity and
generality.  I think most people want to strive for work
that is the most general purpose and handles the most
cases, by its very nature this type of design is very flexible
and can transcend the boundaries of many architectures.

>    1) It postpones that debate till deployment
>    2) IETF already incorporates deployment
>       experience as part of its process
>    3) "Architectures" have a tendency to become
>       ossified when they are too narrow.
>    4) Leaving the deployment architecture unspoken
>       is a feature, not a bug. There are many
>       reuses of existing protocols which probably
>       wouldn't have happened if they had to be
>       vetted against some architecture.
>

I would argue that there are probably just as many
problems caused by existing protocols that may have
been prevented with a bit more "architecture" work.

In many cases it may boil down to the size of the WG.
In the case of SeaMoby its a pretty big group and to
handle the diverging opinions it would seem to me
that architecture is a useful tool.

If it were me and Peter coding it... wait a minute, we
finished this stuff in 1998!

Regards,

-Phil

// END RANT

---

From: "Charles E. Perkins" <[email-masked]>
Date: Wed, 11 Apr 2001 13:49:18 -0700

Hello Phil,

If you think there are architectural issues that need attention,
can you say what they are?

If you can say what they are, do you think there is value in
bringing the list items to the attention of the IAB?

> stuff that can often be provided by an architecture).

It can also be provided by a terminology document and a requirements
document.

> a common vision going.  In these situations, architecture is done implicitly,

But four out of five startups fail.  We need to keep the failure average
lower in the IETF, I reckon.

> lot of these days under the covers) it is now.

That's because the Internet is huge enough to encompass a
major diversity of applications and utilizations.  I just hope
we can avoid the tragedy of the commons.  Sometimes it seems
inevitable, as clever people make local optimizations that
damage the overall good.  Architecture with teeth could help
in this regard.  But the market can dump any solution it
has not been groomed to prefer, architecture or not.  Examples
abound.  Worse, if the architecture has teeth, and it's not
great according to your definition, then you won't like the
teeth marks.

..........

> finished this stuff in 1998!

But coding isn't architecture.  And I know you didn't say
it was.  But your comment here would be more appropriate in
a discussion about why the IETF should NOT DO architecture.

I absolutely agree that architecture is needed.  I just question
whether it belongs in a working group like [seamoby].  It would
seem to be more appropriate at the area directorate level,
or probably better within a group like the IAB.  I wonder if
there should be an [iawg].  We'd need some wild-eyed masochists
as chairs, I reckon.

Regards,
Charlie P.

---

From: "Phil Neumiller" <[email-masked]>
Date: Wed, 11 Apr 2001 16:29:22 -0500

> can you say what they are?

I really don't need rocket science to explain this and this will
probably will offend some folks and maker others happy...

I guess one big one is as follows:  the IETF seems to be good
at solving problems at the protocol scale, i.e. I need to transport
data of type X between boxes of type Y with bearer characteristics Z
and signalling characteristics Q.  Which is fine for some things.

It does not handle well at all, other SDO's coming into the IETF
with their own stove-pipe architectures and expecting the IETF
to work really hard to preserve or build towards those transient
architectures.  The IETF should be in a good position to influence
others to adopt the architecture of the global Interent rather than
be pandering to the voices of whichever group can send the most
bodies to a WG list or microphone (one way to gain consensus is
to outnumber your adversaries - Cisco comes to mind!!).

The global internet is hierarchical in the DNS systems and the way
prefixes are aggragated, peer-to-peer with respect to IP transport,
and client server with respect to DNS and the interior / exterior
gateway protocol relationships of edge versus core.   It would
seem that this particular way of arranging routers has proven itself
a viable architecture with planetary scalability, albeit with some
very serious growing pains that it is still battling daily.

At one time it was fashionable to say "Apple won" with respect to
the way Microsoft kept stealing (I mean succesfully marketing)
everything the Mac did.  Is it not time to say the same about the
Internet architecture?

CONCLUSION of RANT (we can only hope!)

The INTERNET WON!  Now, if you build a system, you probably
want to take a close look at the arrangement of its constituent boxes
and sort of make sure they are arranged in a manner consistent with
the IP routers that constitute the global Internet (and I am sure that
Cisco, Redback, etc) would tend to agree with this view!

-pdn (Then again...  I could be dead wrong!)

---

From: Arthur Ross <[email-masked]>
Date: Wed, 11 Apr 2001 16:11:21 -0700

>-pdn (Then again...  I could be dead wrong!)

<Begin RANT>

Au contraire Phil ... I think you are dead right.

Echoing what I said in my letter to the WSJ last week ("Readers Respond" to
the Journal's "Capital" column on March 29 re spectrum auctions), I am
DELIGHTED that this discussion is being floated in a public, deliberative
forum that is well-known for thouroughly thrashing out the technical
issues. The notion of overlaying IP somehow on the 3GPPx PSTN-centric
(Bell-shaped?) architectures (SS7, HLR, VLR, etc.) has always seemed to me
obviously inappropriate, bordering on insane. One can only conclude that
the potentially lucrative, vertically-integrated services envisioned by the
auction winners motivate the obviously inappropriate architectural models.

These discussions of paging, context transfer, etc, have been suffering
from big-time disconnect of the implicit models brought by the participants
from their various disjoint universes. This debate on requirements has, I
think, been very healthy in that it has been uncovering & airing these
implicit, inconsistent world views.

As you say, the underlying conceptual model (note my careful choice of
words - not necessarily an "architecture") needs to be confronted. I
wholeheartedly support the notion of formal definition. This might entail
only identification of the functional entities, and a minimal set of
assumptions about their interconnection rules and properties. But it is
needed.

The obvious, stunning, global success of IP stems, in large part, from the
EXTREMELY SIMPLE underlying conceptual model. That model needs to be
mobile-ized, while retaining that underlying minimalist philosophy.

I probably don't need to tell anyone that the outcome of this will have
ENORMOUS consequences for the business of wireless telecom. WW-III(G, that
is) was not really the trans-atlantic chip rate, modulation & coding
skirmish, which ended in a stalemate; the real WW-III will be this - the
IP-centric world view versus the PSTN-centric world view.

<End RANT>

   -- Regards,
   -- Arthur

---

From: Jim Bound <[email-masked]>
Date: Thu, 12 Apr 2001 10:43:20 -0400 (EDT)

Charlie,

I strongly disagree that the architecture belongs in the Area Director or
IAB.  That is a very bad idea.  Direction statements are fine.  But good
architecture is a very serious process to accomplish what Phil stated so
that multiple solutions can be attained.  It also may permit a more
laizzes-faire approach to implementation with interoperability the only
goal from our specs in this and other working groups in the IETF.

If an architecture draft or picture will help us declare and put on the
table all our assumptions then its worth its weight in gold to this
working group.  One reason for failure and drafts numbers greater than
lets xxxxx-05.txt is precisely what Phil stated and I would add to that
the working group members were operating on different assumptions which is
death to a clear consensus solution.

/jim