Subject: [arch-d] On the (f)utility of prescriptive architecture

From: "Brian Trammell (IETF)" <[email-masked]>
Date: Sat, 21 Mar 2020 16:21:33 +0100

Hi Stewart, all,

I’ll leave the question of the appropriateness or this side meeting announcement to the side, but I did want to respond to the notion that the IAB should have some top-down master plan for the Internet, and that the lack of such is evidence that the IAB is not properly tracking changes in the Internet itself.

Architectural guidance from the IAB has admittedly been somewhat meta: 5218, 6709, and 8170 on how protocols themselves emerge and evolve in a multi-protocol, multi-implementor, multi-operator environment; 6973, 7754, and 7624 on privacy, access control, and confidentiality concerns of protocols up the stack; 8546 and 8558 on the implications additional confidentiality on the wire has on transport design and operations, and so on. Each of these efforts has been in parallel to related efforts in the IETF (I would argue that the design and deployment of QUIC, for instance, is influenced, in some cases deeply, by all of the cited RFCs).

True, there is no overarching prescriptive “architecture for the Internet”, because IMO developing such a thing would be a colossal waste of time. In the absence of a lever with which to impose architectural will, in the best case the broad and diverse community that builds and runs the Internet would look at such a thing, maybe read the abstract, say “yeah that’s nice” then go back to the business of keeping things running. What is more useful is descriptive architecture in the small: looking at the way things are and drawing insights toward evolutionary change; the RFCs cited above are all examples of this sort of thing.

Most of the problems the long history of IP replacements (including the ones I’ve worked on, and continue to work on) over the years have identified aren’t really technical, or at least are not technical in tractably addressable ways (the speed of light and the fact that all operations one can do in a network have strictly nonnegative latency are problems as old and hard as the non existence of perpetual motion machines). Rather, they are issues of inter organizational relationships and business models: rethinking inter domain routing or end to end QoS require an alignment of incentives that seldom emerges organically in a multi operator network. If you’d like the IAB to address these authoritatively, you can talk to your friendly local NomCom about appointing some economists, but it’s not clear to me that that’s the best business for the IAB to be in.

Cheers, Brian

Sent from my iPhone

> On 21 Mar 2020, at 12:11, Stewart Bryant <[email-masked]> wrote:
> 
> ...and also when the IAB fails to drive the changes needed in the Internet to support the evolving applications requirements or to properly track the changes in the Internet itself.
> 
> I did kind of think that the IAB would have had a 10 to 20 year evolution plan front and centre of its thinking, but I have never seen any evidence that it regards that to be one of its core responsibilities.
> 
> I also thought that the IAB ought to be an enabler of this thought process by encouraging input form others, but rather than that it seems to be a tightly closed community.
> 
> ... just saying.
> 
> - Stewart
> 
> 
>> On 20 Mar 2020, at 23:15, Tony Li <[email-masked]> wrote:
>> 
>> 
>> And I hate to see the IAB stomp on discussions.
>> 
>> T
>> 
>> 
>>>> On Mar 20, 2020, at 4:09 PM, Melinda Shore <[email-masked]> wrote:
>>> 
>>> On 3/20/20 3:03 PM, Stephen Farrell wrote:
>>>> AFAIK this is basically an initiative driven by one or
>>>> a small set of vendors. It is not an IAB activity and
>>>> this list is. ISTM somewhat cheeky to cast this as if
>>>> it were sort-of "official" by sending ICS invites to
>>>> this list and suggesting this list be used for follow
>>>> ups. I'm saying that as an individual and have not
>>>> asked other IAB folks what they think, but again
>>>> speaking personally, I'd be much happier if people
>>>> and organisations had a bit more style.
>>> 
>>> That was close to my reaction, as well.
>>> 
>>> Melinda
>>> 
>>> -- 
>>> Melinda Shore
>>> [email-masked]
>>> 
>>> Software longa, hardware brevis
>>> 
>>> _______________________________________________
>>> Architecture-discuss mailing list
>>> [email-masked]
>>> https://www.ietf.org/mailman/listinfo/architecture-discuss
>> 
>> _______________________________________________
>> Architecture-discuss mailing list
>> [email-masked]
>> https://www.ietf.org/mailman/listinfo/architecture-discuss
> 
> _______________________________________________
> Architecture-discuss mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/architecture-discuss

---

From: Stewart Bryant <[email-masked]>
Date: Sun, 22 Mar 2020 09:19:14 +0000

> On 21 Mar 2020, at 15:21, Brian Trammell (IETF) <[email-masked]> wrote:
> 
> Hi Stewart, all,
> 

Maybe I have missed it, but I have not seen any IAB work with the community on the de facto fundamental restructuring of the Internet into a series of walled gardens with best effort global traffic on a path to become a minority interest.

For those that have not noticed it, I recommend reading Geoff Hustons work on the death of transit. This points to a huge elephant that is sitting on the middle of the room that we completely ignore.

Even if the IAB is not able to directly design the architecture of the Internet, it ought to at least be the body that reminds us all what it actually is, and provides some insight into both the opportunities and the threats.

From my perspective, and it is one that we articulate in our draft, the change is very much an opportunity in that it returns the Internet into an Inter-net and provides mechanisms that allow us to divide and conquer the intractable technical, operational and economic problem of advancing the capability of a global scale network. 

> True, there is no overarching prescriptive “architecture for the Internet”, because IMO developing such a thing would be a colossal waste of time. In the absence of a lever with which to impose arc…

Those RFCs largely concern things that run over the Internet data paths, not the way the we might align those paths with future needs.

There is no Internet equivalent of what 3GPP does, and continues to do for wireless networks. Nor the continuous evolution process that the IEEE has with Ethernet. We work on the basis that the data plane we designed many years ago is unchangeable except in maters of relatively minor detail such as changing the length of an IP address.

> 
> Most of the problems the long history of IP replacements (including the ones I’ve worked on, and continue to work on) over the years have identified aren’t really technical, or at least are not technical in tractably addressable ways (the speed of light and the fact that all operations one can do in a network have strictly nonnegative latency are problems as old and hard as the non existence of perpetual motion machines). Rather, they are issues of inter organizational relationships and business models: rethinking inter domain routing or end to end QoS require an alignment of incentives that seldom emerges organically in a multi operator network.

The point we make in the draft, and is one we need to develop in future versions, is that there is an evolution in the Internet architecture that make it feasible to implement change in a way that has hitherto not been possible. Furthermore there is an opportunity for an economic model that supports such change. 

> If you’d like the IAB to address these authoritatively, you can talk to your friendly local NomCom about appointing some economists, but it’s not clear to me that that’s the best business for the IAB to be in.

I had not thought of economists per se, but now you mention it that might be a good idea,

We, the IETF do need to understand the economic and, for that matter, governmental (taken from the perspective of a global exert rather than a particular government) impacts of our technical decisions and it would make sense for them to be part of the long term oversight role the IAB is chartered to take.

- Stewart

---

From: S Moonesamy <[email-masked]>
Date: Sun, 22 Mar 2020 04:02:05 -0700

Hi Brian,
At 08:21 AM 21-03-2020, Brian Trammell (IETF) wrote:
>True, there is no overarching prescriptive 
>"architecture for the Internet", because IMO 
>developing such a thing would be a colossal 
>waste of time. In the absence of a lever with 
>which to impose architectural will, in the best 
>case the broad and diverse community that builds 
>and runs the Internet would look at such a 
>thing, maybe read the abstract, say "yeah that's 
>nice" then go back to the business of keeping 
>things running. What is more useful is 
>descriptive architecture in the small: looking 
>at the way things are and drawing insights 
>toward evolutionary change; the RFCs cited above 
>are all examples of this sort of thing.

I read Stewart's message differently.  If I 
understood it correctly, it was about thinking 
about the long-term evolution of the Internet.  A 
person can look at the details (what is referred 
to as "in the small") if he/she has the time to 
do that.  The person might still have to look at 
the broad picture if he/she is interested in the 
evolutionary/architectural aspects.

>Most of the problems the long history of IP 
>replacements (including the ones I've worked on, 
>and continue to work on) over the years have 
>identified aren't really technical, or at least 
>are not technical in tractably addressable ways 
>(the speed of light and the fact that all 
>operations one can do in a network have strictly 
>nonnegative latency are problems as old and hard 
>as the non existence of perpetual motion 
>machines). Rather, they are issues of inter 
>organizational relationships and business 
>models: rethinking inter domain routing or end 
>to end QoS require an alignment of incentives 
>that seldom emerges organically in a multi 
>operator network. If you'd like the IAB to 
>address these authoritatively, you can talk to 
>your friendly local NomCom about appointing some 
>economists, but it's not clear to me that that's 
>the best business for the IAB to be in.

Some points (please see above) could be doable 
without replacing IAB members with economists.

There is a message from the IAB at 
https://mailarchive.ietf.org/arch/msg/ietf/AWEWI7rCmbOzifT5xQRpyciPLE8/ 
It is understandable that it has to see to the 
other aspects of its Charter.  I could not find 
anything [1] in there which takes a "let's think 
ahead" approach or a "let's rethink".

The recent events could produce a significant shift in the existing models.

Regards,
S. Moonesamy

1. There may be an exception to that.  It may 
take a few years to see whether that is actually the case.

---

From: Marie-Jose Montpetit <[email-masked]>
Date: Sun, 22 Mar 2020 09:14:50 -0400

Stewart: I think you that you are a bit unfair about the IETF not being as
worthy of 3GPP or IEEE but I will not launch a polemic on this. But I will
suggest you may want to be looking at what is happening in the IRTF wrt
looking at Internet evolution. I actually smiled at your "We work on the
basis that the data plane we designed many years ago is unchangeable” as we
are looking at programming that data plane in the COINRG group not changing
a few bits in the header.

mjm (with my coinrg co-chair hat)

Marie-José Montpetit, Ph.D.
[email-masked]

On March 22, 2020 at 5:20:47 AM, Stewart Bryant ([email-masked])
wrote:

> I’ll leave the question of the appropriateness or this side meeting
announcement to the side, but I did want to respond to the notion that the
IAB should have some top-down master plan for the Internet, and that the
lack of such is evidence that the IAB is not properly tracking changes in
the Internet itself.
>
> Architectural guidance from the IAB has admittedly been somewhat meta:
5218, 6709, and 8170 on how protocols themselves emerge and evolve in a
multi-protocol, multi-implementor, multi-operator environment; 6973, 7754,
and 7624 on privacy, access control, and confidentiality concerns of
protocols up the stack; 8546 and 8558 on the implications additional
confidentiality on the wire has on transport design and operations, and so
on. Each of these efforts has been in parallel to related efforts in the
IETF (I would argue that the design and deployment of QUIC, for instance,
is influenced, in some cases deeply, by all of the cited RFCs).

Maybe I have missed it, but I have not seen any IAB work with the community
on the de facto fundamental restructuring of the Internet into a series of
walled gardens with best effort global traffic on a path to become a
minority interest.

For those that have not noticed it, I recommend reading Geoff Hustons work
on the death of transit. This points to a huge elephant that is sitting on
the middle of the room that we completely ignore.

Even if the IAB is not able to directly design the architecture of the
Internet, it ought to at least be the body that reminds us all what it
actually is, and provides some insight into both the opportunities and the
threats.

>From my perspective, and it is one that we articulate in our draft, the
change is very much an opportunity in that it returns the Internet into an
Inter-net and provides mechanisms that allow us to divide and conquer the
intractable technical, operational and economic problem of advancing the
capability of a global scale network.

>
> True, there is no overarching prescriptive “architecture for the
Internet”, because IMO developing such a thing would be a colossal waste of
time. In the absence of a lever with which to impose architectural will, in
the best case the broad and diverse community that builds and runs the
Internet would look at such a thing, maybe read the abstract, say “yeah
that’s nice” then go back to the business of keeping things running. What
is more useful is descriptive architecture in the small: looking at the way
things are and drawing insights toward evolutionary change; the RFCs cited
above are all examples of this sort of thing.

Those RFCs largely concern things that run over the Internet data paths,
not the way the we might align those paths with future needs.

There is no Internet equivalent of what 3GPP does, and continues to do for
wireless networks. Nor the continuous evolution process that the IEEE has
with Ethernet. We work on the basis that the data plane we designed many
years ago is unchangeable except in maters of relatively minor detail such
as changing the length of an IP address.

>
> Most of the problems the long history of IP replacements (including the
ones I’ve worked on, and continue to work on) over the years have
identified aren’t really technical, or at least are not technical in
tractably addressable ways (the speed of light and the fact that all
operations one can do in a network have strictly nonnegative latency are
problems as old and hard as the non existence of perpetual motion
machines). Rather, they are issues of inter organizational relationships
and business models: rethinking inter domain routing or end to end QoS
require an alignment of incentives that seldom emerges organically in a
multi operator network.

The point we make in the draft, and is one we need to develop in future
versions, is that there is an evolution in the Internet architecture that
make it feasible to implement change in a way that has hitherto not been
possible. Furthermore there is an opportunity for an economic model that
supports such change.

> If you’d like the IAB to address these authoritatively, you can talk to
your friendly local NomCom about appointing some economists, but it’s not
clear to me that that’s the best business for the IAB to be in.

I had not thought of economists per se, but now you mention it that might
be a good idea,

We, the IETF do need to understand the economic and, for that matter,
governmental (taken from the perspective of a global exert rather than a
particular government) impacts of our technical decisions and it would make
sense for them to be part of the long term oversight role the IAB is
chartered to take.

- Stewart

>> ...and also when the IAB fails to drive the changes needed in the
Internet to support the evolving applications requirements or to properly
track the changes in the Internet itself.
>>
>> I did kind of think that the IAB would have had a 10 to 20 year
evolution plan front and centre of its thinking, but I have never seen any
evidence that it regards that to be one of its core responsibilities.
>>
>> I also thought that the IAB ought to be an enabler of this thought
process by encouraging input form others, but rather than that it seems to
be a tightly closed community.

---

From: Jared Mauch <[email-masked]>
Date: Sun, 22 Mar 2020 11:36:34 -0400

> Even if the IAB is not able to directly design the architecture of the Internet, it ought to at least be the body that reminds us all what it actually is, and provides some insight into both the op…

	I live much of this daily and am working with our internal teams to 
cope with the changes in the industry on a regular basis.  We ourselves
built our own backbone to get around regional networking issues that many
are aware of.  It's often in our economic advantage to take our fate into
our own hands for a number of reasons:

  1) networks have no incentive to ensure they have off-network connectivity
  2) networks have no incentive to improve off-network performance
  3) networks have no incentive to lower costs, or can be immune to what
     might be otherwise market pressures.
  4) content providers and delivery networks have paying customers who
     outsource fixing or working around the problem.
  5) private networks have better performance than public networks
  6) private networks are harder to measure than public networks
  7) we can understand the properties of our own private network and deploy
     non-standard fixes to our problems (eg: SR, BGP-LU) that have zero place
     in public networks
  8) costs are significantly lower in a private network vs public

	For these reasons amongst others, it's been in my employers best
interest to privatize traffic, but this has consequences that impact
existing models.

	While Geoff is often right IMO, he's also wrong.  Transit is dead,
long live transit.  You may reach your VPS with a single network hop
from your broadband service directly peering with your cloud provider,
they still rely on transit services to reach networks they do not interconnect
with.  We have the same situations and often hear from providers when
we start using paid transit links that can't handle the load due to #1 or #2
above.

	I have observations about how global players do better than what
I call the super-regional players (eg: multi-market incumbents that do
not span country boundaries).  If someone exists in many countries or
continents, they are more likely to be well suited for traffic vs
someone who owns a market.

	Building last mile is expensive, I can tell you this first hand
as my side job is running a small FTTH network.  It's also very rewarding
if you can adapt to the local market conditions.

	I expect that my perspective on many of these things contributed
to why my virtual badge has a dot on it starting later this week.  It's
something I care about and suspect I'll bring this perspective to the
table in a way others perhaps haven't.

	- Jared

---

From: Stephen Farrell <[email-masked]>
Date: Sun, 22 Mar 2020 22:09:32 +0000

Hi Stewart,

On 22/03/2020 09:19, Stewart Bryant wrote:
> 
> From my perspective, and it is one that we articulate in our draft,

Just as a reminder, that's [1].

I had a read. I'm unconvinced by a lot of the argument
(many of the assertions made have no backing) but do agree
that there are topics there worthy of open discussion,
where participants are highly likely to arrive with very
different starting points. We saw exactly that when we
had earlier discussions about whether applications would
or would not want to expose information to the network.
I don't see how the kind of set-piece side-meeting is
likely to progress such discussion in a useful direction
myself.

I also agree with Brian that the idea of the IAB, or of
any single vendor, or of any international organisation,
setting out the architecture that'll be followed by all
of us in a decade's time is... more than unconvincing.

Cheers,
S.

[1] https://tools.ietf.org/html/draft-bryant-arch-fwd-layer-ps-00

---

From: Ted Hardie <[email-masked]>
Date: Mon, 23 Mar 2020 10:06:18 -0700

Hi Stewart,

On Sun, Mar 22, 2020 at 2:20 AM Stewart Bryant <[email-masked]>
wrote:

>
> Maybe I have missed it, but I have not seen any IAB work with the
> community on the de facto fundamental restructuring of the Internet into a
> series of walled gardens with best effort global traffic on a path to
> become a minority interest.
>
>
You might want to take a look at the background material for the DEDR
workshop: https://www.iab.org/activities/workshops/dedr-workshop/ .  It
points to some of the previous work of the IAB in defining successful
protocols and successful protocol transitions, then tackles the question of
"What happens when the environment the protocol was designed for
changes?".  Consolidation was a big part of both the input documents and
that discussion, and Geoff and others focused on what that means for
modern networks.  model-t and chirp are both discussions that emerged from
that.

regards,

Ted Hardie

---

From: Geoff Huston <[email-masked]>
Date: Mon, 23 Mar 2020 18:32:09 +0000

> On 24 Mar 2020, at 4:06 am, Ted Hardie <[email-masked]> wrote:
> 
> Hi Stewart,
> 
> On Sun, Mar 22, 2020 at 2:20 AM Stewart Bryant <[email-masked]> wrote:
> 
> You might want to take a look at the background material for the DEDR workshop: https://www.iab.org/activities/workshops/dedr-workshop/ .  It points to some of the previous work of the IAB in defining successful protocols and successful protocol transitions, then tackles the question of "What happens when the environment the protocol was designed for changes?".  Consolidation was a big part of both the input documents and that discussion, and Geoff and others focused on what that means for modern networks.  model-t and chirp are both discussions that emerged from that.

To chime on in Ted’s note, I found the DEDR workshop to be incredibly interesting - my thoughts after attending it can be found at http://www.potaroo.net/ispcol/2019-06/dedr.pdf

I am not sure what or where you are heading with your comment Stewart. Yes what we call the Internet has changed radically over the past decade in the light of the inexorable expansion of CDNs (http://www.potaroo.net/ispcol/2016-10/xtransit.pdf). But what strikes me as an important observation is that we have not shifted to new protocols and entirely novel infrastructure to support this different form of service behaviour. In fact this entire shift uses the same technology base and the same infrastructure base. Anyone else would call that kind of incredibly flexible architecture that preserves the essential investments in technology and infrastructure an amazing success in architecture. 

The telephone network was a one-trick pony - you spoke into it - and the network was built on the physics and social behaviours of the way people speak to each other. We originally constructed the Internet as a computer facsimile of the telephone network, and for a short period computers used the network in a manner similar to the telephony network. But we adapted and learned and the Internet today is a very different beast. But what never ceases to amaze me is that the essential architectural elements we used at the start are with us today - edge-centric and decentralised control mechanisms, decoupled behaviours, and so on. So what’s your issue here Stewart? What is the _architectural_ discussion that we are missing here?

regards,

Geoff