Re: "The IETF has difficulty solving complex problems" or alternatively Why IMS is a big fat ugly incomprehensiable protocol

[Pekka Nikander <[e-mail]>]

Jari Arkko wrote:
>> - Good architecture and good design. Placement of
>>  functionality in the right place. I suspect that we
>>  don't do enough work in this area. Almost all
>>  of our activities are related to specific protocol
>>  pieces, not so much on how they work together,
>>  what the whole needs to do, what etc.
>>

Henning Schulzrinne wrote:
> These days, this seems to be the domain of the "systems"  
> standardization bodies, such as 3GPP and CableLabs. The 3GPP  
> architecture diagram seems to be a good demonstration object,  
> although it is not directly the fault of the IETF. (I think there  
> are some interesting reasons for complexity here, in particular the  
> need for interworking with legacy technology, that also appear  
> elsewhere.)

I don't think "architecture" necessarily means the kind of "systems"  
architecture that the "systems" standardisation bodies are  
producing.  While the Internet architecture has never been defined in  
terms of nodes and interconnections like the 3GPP architectures  
typically are, I still think we had a fairly well functioning and  
beautiful Internet architecture some 10-15 years back.  So, it may  
just be harder to pinpoint what the Internet architecture was, even  
though I think that, for example, some of Bob Braden's slide sets  
give quite a good idea.

Consequently, the kind of "new" architecture work that I think we  
need might be called by some people something else, perhaps "vision",  
rather than "architecture".   That is, like we've had the e2e  
principle for quite a long time, maybe we should try to develop a  
number of almost as fundable principles, like ones for wireless  
operations, mobility and multi-homing, o & m, distributed security  
management, etc.  Then, by consciously applying those principles to  
existing protocol designs, sometimes perhaps working on  
simultaneously in enhancing an existing protocol and in creating a  
new "version" of the particular protocol, based on a completely  
different architectural design, we might be able to inch to a  
somewhat less complex overall architecture.  OTOH, maybe I am just a  
dreamer and totally off the ground here?

> I suspect a fair amount of complexity is because we had to bolt on  
> various things (NAT traversal, security, reliability or large  
> messages seem common after-market add-ons) or couldn't arrive at  
> decisions during protocol design time.

I pretty much agree.  Furthermore, more generally, I think that the  
current state of the architecture is pretty much a consequence of  
collectively not accepting the reality for a too long time.  In my  
quite humble opinion, a number of vocal people at the IETF have far  
too long been preaching the architecture as it used to be 10-15 years  
back, disparately trying to clung to the ideal and ignoring the  
reality.  As a result, the Internet architecture as-out-there-in-real- 
life has ran over the architecture-as-in-our-heads, causing a  
multitude of point solutions to be built to work around the problems  
in the ideal architecture.

So, as I state in my little web page, I think we really should work  
hard to create a new waist for the architecture.   I, of course, have  
my own theory where the new waist should be and how it should be  
implemented, but I also try to stretch myself here to be as open  
minded as I can in order to better understand the concerns from all  
of the community.  My problem is that I don't know how best to engage  
the community in this kind of discussion, and relatedly, whether  
creating "a vision of a new waist" is possible at all, or at least  
whether it is possible to get any level of acceptance of such a  
vision within the community.

--Pekka Nikander


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