Independent Submission M. Nottingham

Independent Submission M. Nottingham
Request for Comments: 9518 December 2023
Category: Informational
ISSN: 2070-1721

Centralization, Decentralization, and Internet Standards

Abstract

This document discusses aspects of centralization that relate to
Internet standards efforts. It argues that, while standards bodies
have a limited ability to prevent many forms of centralization, they
can still make contributions that assist in the decentralization of
the Internet.

Status of This Memo

This document is not an Internet Standards Track specification; it is
published for informational purposes.

This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not candidates for any level of Internet Standard;
see Section 2 of RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9518.

Copyright Notice

Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents

1. Introduction
2. Centralization
2.1. Centralization Can Be Harmful
2.2. Centralization Can Be Helpful
3. Decentralization
3.1. Decentralization Strategies
3.1.1. Federation
3.1.2. Distributed Consensus
3.1.3. Operational Governance
4. What Can Internet Standards Do?
4.1. Bolster Legitimacy
4.2. Focus Discussion of Centralization
4.3. Target Proprietary Functions
4.4. Enable Switching
4.5. Control Delegation of Power
4.6. Enforce Boundaries
4.7. Consider Extensibility Carefully
4.8. Reuse What Works
5. Future Work
6. Security Considerations
7. IANA Considerations
8. Informative References
Acknowledgements
Author's Address

1. Introduction

One of the Internet's defining features is its lack of any single
point of technical, political, or economic control. Arguably, that
characteristic assisted the Internet's early adoption and broad
reach: permission is not required to connect to, deploy an
application on, or use the Internet for a particular purpose, so it
can meet diverse needs and be deployed in many different
environments.

Although maintaining that state of affairs remains a widely espoused
goal, consistently preserving it across the range of services and
applications that people see as "the Internet" has proven elusive.
Whereas early services like the Network News Transfer Protocol (NNTP)
and email had multiple interoperable providers, many contemporary
platforms for content and services are operated by single commercial
entities without any interoperable alternative -- to the point where
some have become so well-known and important to people's experiences
that they are commonly mistaken for the Internet itself [Komaitis].

These difficulties call into question what role architectural design
-- in particular, that overseen by open standards bodies such as the
IETF -- can and should play in controlling centralization of the
Internet.

This document argues that, while decentralized technical standards
may be necessary to avoid centralization of Internet functions, they
are not sufficient to achieve that goal because centralization is
often caused by non-technical factors outside the control of
standards bodies. As a result, standards bodies should not fixate on
preventing all forms of centralization; instead, they should take
steps to ensure that the specifications they produce enable
decentralized operation.

Although this document has been discussed widely in the IETF
community (see the Acknowledgements section), it represents the views
of the author, not community consensus. Its primary audience is the
engineers who design and standardize Internet protocols. Designers
of proprietary protocols and applications can benefit from
considering these issues, especially if they intend their work to be
considered for eventual standardization. Policymakers can use this
document to help characterize abuses that involve centralized
protocols and applications and evaluate proposed remedies for them.

Section 2 defines centralization, explains why it is often
undesirable but sometimes beneficial, and surveys how it occurs on
the Internet. Section 3 explores decentralization and highlights
some relevant strategies, along with their limitations. Section 4
makes recommendations about the role that Internet standards can play
in controlling centralization. Section 5 concludes by identifying
areas for future work.

2. Centralization

In this document, "centralization" is the state of affairs where a
single entity or a small group of them can observe, capture, control,
or extract rent from the operation or use of an Internet function
exclusively.

Here, "entity" could be a person, group, or corporation. An
organization might be subject to governance that mitigates
centralization risk (see Section 3.1.3), but that organization is
still a centralizing entity.

"Internet function" is used broadly in this document. Most directly,
it might be an enabling protocol already defined by standards, such
as IP [RFC791], BGP [RFC4271], TCP [RFC9293], or HTTP [HTTP]. It
might also be a proposal for a new enabling protocol or an extension
to an existing one.

Because people's experience of the Internet are not limited to
standards-defined protocols and applications, this document also
considers centralization in functions built on top of standards --
for example, social networking, file sharing, financial services, and
news dissemination. Likewise, the networking equipment, hardware,
operating systems, and software that act as enabling technologies for
the Internet can also impact centralization. The supply of Internet
connectivity to end users in a particular area or situation can
exhibit centralization, as can the supply of transit between networks
(so called "Tier 1" networks).

This definition of centralization does not capture all types of
centralization. Notably, technical centralization (for example,
where a machine or network link is a single point of failure) is
relatively well understood by engineers; it can be mitigated,
typically by distributing a function across multiple components. As
we will see, such techniques might address that type of
centralization while failing to prevent control of the function
falling into few hands. A failure because of a cut cable, power
outage, or failed server is well understood by the technical
community but is qualitatively different from the issues encountered
when a core Internet function has a gatekeeper.

Likewise, political centralization (for example, where a country is
able to control how a function is supplied across the whole Internet)
is equally concerning but is not considered in depth here.

Even when centralization is not currently present in a function, some
conditions make it more likely that centralization will emerge in the
future. This document uses "centralization risk" to characterize
that possibility.

2.1. Centralization Can Be Harmful

Many engineers who participate in Internet standards efforts have an
inclination to prevent and counteract centralization because they see
the Internet's history and architecture as incompatible with it. As
a "large, heterogeneous collection of interconnected systems" [BCP95]
the Internet is often characterized as a "network of networks" whose
operators relate as peers that agree to facilitate communication
rather than experiencing coercion or requiring subservience to
others' requirements. This focus on independence of action is
prevalent in the Internet's design -- for example, in the concept of
an "autonomous system".

Reluctance to countenance centralization is also rooted in the many
potentially damaging effects that have been associated with it,
including:

* _Power Imbalance_: When a third party has unavoidable access to
communications, they gain informational and positional advantages
that allow observation of behavior (the "panopticon effect") and
shaping or even denial of behavior (the "chokepoint effect"):
capabilities that those parties (or the states that have authority
over them) can use for coercive ends [FarrellH] or even to disrupt
society itself. Just as [Madison] describes good governance of
the US states, good governance of the Internet requires that power
over any function not be consolidated in one place without
appropriate checks and balances.

* _Limits on Innovation_: A party with the ability to control
communication can preclude the possibility of "permissionless
innovation", i.e., the ability to deploy new, unforeseen
applications without requiring coordination with parties other
than those you are communicating with.

* _Constraints on Competition_: The Internet and its users benefit
from robust competition when applications and services are
available from many providers, especially when those users can
build their own applications and services based upon interoperable
standards. When a centralized service or platform must be used
because no substitutes are suitable, it effectively becomes an
essential facility, which opens the door to abuse of power.

* _Reduced Availability_: Availability of the Internet (and
applications and services built upon it) improves when there are
many ways to obtain access. While service availability can
benefit from the focused attention of a large centralized
provider, that provider's failure can have a disproportionate
impact on availability.

* _Monoculture_: The scale available to a centralized provider can
magnify minor flaws in features to a degree that can have broad
consequences. For example, a single codebase for routers elevates
the impact of a bug or vulnerability; a single recommendation
algorithm for content can have severe social impact. Diversity in
functions' implementations leads to a more robust outcome when
viewed systemically because "progress is the outcome of a trial-
and-error evolutionary process of many agents interacting freely"
[Aligia].

* _Self-Reinforcement_: As widely noted (e.g., see [Abrahamson]), a
centralized provider's access to data allows it the opportunity to
make improvements to its offerings while denying such access to
others.

The relationship between these harms and centralization is often
complex. It is not always the case that centralization will lead to
them; when it does, there is not always a direct and simple trade-
off.

For example, consider the relationship between centralization and
availability. A centrally operated system might be more available
because of the resources available to a larger operator, but their
size creates greater impact when a fault is encountered.
Decentralized systems can be more resilient in the face of some forms
of failure but less so in other ways; for example, they may be less
able to react to systemic issues and might be exposed to a larger
collection of security vulnerabilities in total. As such, it cannot
be said that centralization reduces availability in all cases: nor
does it improve it in all cases.

This tension can be seen in areas like the cloud and mobile Internet
access. If a popular cloud-hosting provider were to become
unavailable (whether for technical or other reasons), many Internet
experiences might be disrupted (especially due to the multiple
dependencies that a modern website often has; see [Kashaf]).
Likewise, a large mobile Internet access provider might have an
outage that affects hundreds of thousands of its users or more --
just as previous issues at large telephone companies precipitated
widespread outages [PHONE].

In both cases, the services are not technically centralized; these
operators have strong incentives to have multiple redundancies in
place and use various techniques to mitigate the risk of any one
component failing. However, they generally do rely upon a single
codebase, a limited selection of hardware, a unified control plane,
and a uniform administrative practice: each of which might
precipitate a widespread failure.

If there were only one provider for these services (like the
telephone networks of old), they would easily be considered to be
centralized in a way that has significant impact upon availability.
However, many cloud providers offer similar services. In most
places, there are multiple mobile operators available. That weakens
the argument that there is a link between centralization and their
availability because the function's users can switch to other
providers or use more than one provider simultaneously; see
Section 4.4.

These circumstances suggest one area of inquiry when considering the
relationship between centralization and availability of a given
function: what barriers are there to switching to other providers
(thereby making any disruptions temporary and manageable) or to using
multiple providers simultaneously (to mask the failure of a single
operator)?

Another example of the need for nuance can be seen when evaluating
competitive constraints. While making provision of various Internet
functions more competitive may be a motivation for many engineers,
only courts (and sometimes regulators) have the authority to define a
relevant market and determine that a behavior is anticompetitive. In
particular, market concentration does not always indicate competition
issues; therefore, what might be considered undesirable
centralization by the technical community might not attract
competition regulation.

2.2. Centralization Can Be Helpful

The potential damaging effects of centralization listed above are
widely appreciated. Less widely explored is the reliance on
centralization by some protocols and applications to deliver their
functionality.

Centralization is often present due to technical necessity. For
example, a single globally coordinated "source of truth" is by nature
centralized -- such as in the root zone of the Domain Name System
(DNS), which allows human-friendly naming to be converted into
network addresses in a globally consistent fashion.

Or, consider IP address allocation. Internet routing requires
addresses to be allocated uniquely, but if a single government or
company were to capture the addressing function, the entire Internet
would be at risk of abuse by that entity. Similarly, the Web's trust
model requires a Certificate Authority (CA) to serve as the root of
trust for communication between browsers and servers, bringing the
centralization risk, which needs to be considered in the design of
that system.

Protocols that need to solve the "rendezvous problem" to coordinate
communication between two parties who are not in direct contact also
require centralization. For example, chat protocols need to
coordinate communication between two parties that wish to talk; while
the actual communication can be direct between them (so long as the
protocol facilitates that), the endpoints' mutual discovery typically
requires a third party at some point. From the perspective of those
two users, the rendezvous function has a centralization risk.

Even when not strictly necessary, centralization can create benefits
for a function's users and for society.

For example, it has long been recognized that the efficiencies that
come with economies of scale can lead to concentration [Demsetz].
Those efficiencies can be passed on to users as higher quality
products and lower costs, and they might even enable provision of a
function that was not viable at smaller scale.

Complex and risky functions like financial services (e.g., credit
card processing) are often concentrated into a few specialized
organizations where they can receive the focused attention and
expertise that they require.

Centralization can also provide an opportunity for beneficial
controls to be imposed. [Schneider2] notes that "centralized
structures can have virtues, such as enabling publics to focus their
limited attention for oversight, or forming a power bloc capable of
challenging less-accountable blocs that might emerge. Centralized
structures that have earned widespread respect in recent centuries --
including governments, corporations, and nonprofit organizations --
have done so in no small part because of the intentional design that
went into those structures".

This can be seen when a function requires governance to realize
common goals and protect minority interests. For example, content
moderation functions impose community values that many see as a
benefit. Of course, they can also be viewed as a choke point where
inappropriate controls are able to be imposed if that governance
mechanism has inadequate oversight, transparency, or accountability.

Ultimately, deciding when centralization is beneficial is a judgment
call. Some protocols cannot operate without a centralized function;
others might be significantly enhanced for certain use cases if a
function is centralized or might merely be more efficient. Although,
in general, centralization is most concerning when it is not broadly
held to be necessary or beneficial; when it has no checks, balances,
or other mechanisms of accountability; when it selects "favorites"
that are difficult (or impossible) to displace; and when it threatens
the architectural features that make the Internet successful.

3. Decentralization

While the term "decentralization" has a long history of use in
economics, politics, religion, and international development, [Baran]
gave one of the first definitions relevant to computer networking as
a condition when "complete reliance upon a single point is not always
required".

Such technical centralization (while not a trivial topic) is
relatively well understood. Avoiding all forms of centralization --
including non-technical ones -- using only technical tools (like
protocol design) is considerably more difficult. Several issues are
encountered.

First, and most critically, technical decentralization measures have,
at best, limited effects on non-technical forms of centralization.
Or, per [Schneider1], "decentralized technology alone does not
guarantee decentralized outcomes". As explored below in Section 3.1,
technical measures are better characterized as necessary but
insufficient to achieve full decentralization of a function.

Second, decentralizing a function requires overcoming challenges that
centralized ones do not face. A decentralized function can be more
difficult to adapt to user needs (for example, introducing new
features or experimenting with user interfaces) because doing so
often requires coordination between many different actors
[Marlinspike]. Economies of scale are more available to centralized
functions, as is data that can be used to refine a function's design.
All of these factors make centralized solutions more attractive to
service providers and, in some cases, can make a decentralized
solution uneconomic.

Third, identifying which aspects of a function to decentralize can be
difficult, both because there are often many interactions between
different types and sources of centralization and because
centralization sometimes only becomes clear after the function is
deployed at scale. Efforts to decentralize often have the effect of
merely shifting centralization to a different place -- for example,
in its governance, implementation, deployment, or ancillary
functions.

For example, the Web was envisioned and widely held to be a
decentralizing force in its early life. Its potential as an enabler
of centralization only became apparent when large websites
successfully leveraged network effects (and secured legal
prohibitions against interoperability, thus increasing switching
costs; see [Doctorow]) to achieve dominance of social networking,
marketplaces, and similar functions.

Fourth, different parties might have good-faith differences on what
"sufficiently decentralized" means based upon their beliefs,
perceptions, and goals. Just as centralization is a continuum, so is
decentralization, and not everyone agrees what the "right" level or
type is, how to weigh different forms of centralization against each
other, or how to weigh potential centralization against other
architectural goals (such as security or privacy).

These tensions can be seen, for example, in the DNS. While some
aspects of the system are decentralized -- for example, the
distribution of the lookup function to local servers that users have
the option to override -- an essentially centralized aspect of the
DNS is its operation as a name space: a single global "source of
truth" with inherent (if beneficial) centralization in its
management. ICANN mitigates the associated risk through multi-
stakeholder governance (see Section 3.1.3). While many believe that
this arrangement is sufficient and might even have desirable
qualities (such as the ability to impose community standards over the
operation of the name space), others reject ICANN's oversight of the
DNS as illegitimate, favoring decentralization based upon distributed
consensus protocols rather than human governance [Musiani].

Fifth, decentralization unavoidably involves adjustments to the power
relationships between protocol participants, especially when it opens
up the possibility of centralization elsewhere. As [Schneider2]
notes, decentralization "appears to operate as a rhetorical strategy
that directs attention toward some aspects of a proposed social order
and away from others", so "we cannot accept technology as a
substitute for taking social, cultural, and political considerations
seriously". Or, more bluntly, "without governance mechanisms in
place, nodes may collude, people may lie to each other, markets can
be rigged, and there can be significant cost to people entering and
exiting markets" [Bodo].

For example, while blockchain-based cryptocurrencies purport to
address the centralization inherent in existing currencies through
technical means, many exhibit considerable concentration of power due
to voting/mining power, distribution of funds, and diversity of the
codebase [Makarov]. Overreliance on technical measures also brings
an opportunity for latent, informal power structures that have their
own risks -- including centralization [Freeman].

Overall, decentralizing a function requires considerable work, is
inherently political, and involves a large degree of uncertainty
about the outcome. If one considers decentralization as a larger
social goal (in the spirit of how the term is used in other, non-
computing contexts), merely rearranging technical functions may lead
to frustration. "A distributed network does not automatically yield
an egalitarian, equitable or just social, economic, political
landscape" [Bodo].

3.1. Decentralization Strategies

This section examines some common strategies that are employed to
decentralize Internet functions and discusses their limitations.

3.1.1. Federation

Protocol designers often attempt to address centralization through
federation, i.e., designing a function in a way that uses independent
instances that maintain connectivity and interoperability to provide
a single cohesive service. Federation promises to allow users to
choose the instance they associate with and accommodates substitution
of one instance for another, lowering switching costs.

However, federation alone is insufficient to prevent or mitigate
centralization of a function because non-technical factors can create
pressure to use a central solution.

For example, the email suite of protocols needs to route messages to
a user even when that user changes network locations or becomes
disconnected for a long period. To facilitate this, SMTP [RFC5321]
defines a specific role for routing users' messages, the Message
Transfer Agent (MTA). By allowing anyone to deploy an MTA and
defining rules for interconnecting them, the protocol avoids a
requirement for a single central server in that role; users can (and
often do) choose to delegate it to someone else or they can run their
own MTA.

Running one's own MTA has become considerably more onerous over the
years due, in part, to the increasingly complex mechanisms introduced
to fight unwanted commercial emails. These costs create an incentive
to delegate one's MTA to a third party who has the appropriate
expertise and resources, contributing to market concentration
[Holzbauer].

Additionally, the measures that MTAs use to identify unwanted
commercial emails are often site specific. Because large MTAs handle
so many more addresses, there is a power imbalance with smaller ones;
if a large MTA decides that email from a small one is unwanted, there
is significant impact on its ability to function and little recourse.

The Extensible Messaging and Presence Protocol (XMPP) [RFC6120] is a
chat protocol that demonstrates another issue with federation: the
voluntary nature of technical standards.

Like email, XMPP is federated to facilitate the rendezvous of users
from different systems - if they allow it. While some XMPP
deployments do support truly federated messaging (i.e., a person
using service A can interoperably chat with someone using service B),
many of the largest do not. Because federation is voluntary, some
operators captured their users into a single service, deliberately
denying them the benefits of global interoperability.

The examples above illustrate that, while federation can create the
conditions necessary for a function to be decentralized, it does not
guarantee that outcome.

3.1.2. Distributed Consensus

Increasingly, distributed consensus technologies (such as a
blockchain) are touted as a solution to centralization. A complete
survey of this rapidly changing area is beyond the scope of this
document, but we can generalize about its properties.

These techniques typically guarantee proper performance of a function
using cryptographic techniques (often, an append-only transaction
ledger). They attempt to avoid centralization by distributing the
operation of a function to members of a sometimes large pool of
protocol participants. Usually, the participants are unknown and
untrusted, and a particular task's assignment to a node for handling
cannot be predicted or controlled.

Sybil attacks (where a party or coordinated parties cheaply create
enough protocol participants to affect how consensus is judged) are a
major concern for these protocols because they would have the effect
of concentrating power into the hands of the attacker. Therefore,
they encourage diversity in the pool of participants using indirect
techniques, such as proof-of-work (where each participant has to show
a significant consumption of resources) or proof-of-stake (where each
participant has some other incentive to execute correctly).

While these measures can be effective in decentralizing a function's
operation, other aspects of its provision can still be centralized:
for example, governance of its design, creation of shared
implementations, and documentation of wire protocols. That need for
coordination is an avenue for centralization even when the function's
operation remains decentralized. For example, the Ethereum "merge"
demonstrated that the blockchain could address environmental concerns
but only through coordinated community effort and governance:
coordination that was benign in most eyes but, nevertheless,
centralized [ETHEREUM].

Furthermore, a protocol or an application composed of many functions
can use distributed consensus for some but still be centralized
elsewhere -- either because those other functions cannot be
decentralized (most commonly, rendezvous and global naming; see
Section 2.2) or because the designer has chosen not to because of the
associated costs and lost opportunities.

These potential shortcomings do not rule out the use of distributed
consensus technologies in every instance, but they do merit caution
against uncritically relying upon these technologies to avoid or
mitigate centralization. Too often, the use of distributed consensus
is perceived as imbuing all parts of a project with
"decentralization".

3.1.3. Operational Governance

Federation and distributed consensus can both create the conditions
for the provision of a function by multiple providers, but they
cannot guarantee it. However, when providers require access to a
resource or cooperation of others to provide that service, that choke
point can itself be used to influence provider behavior -- including
in ways that can counteract centralization.

In these circumstances, some form of governance over that choke point
is necessary to assure the desired outcome. Often, this is through
the establishment of a multi-stakeholder body, which is an
institution that includes representatives of the different kinds of
parties that are affected by the system's operation ("stakeholders")
in an attempt to make well-reasoned, legitimate, and authoritative
decisions.

A widely studied example of this technique is the governance of the
DNS name space, which exhibits centralization as a "single source of
truth" [Moura]. That source of truth is overseen by the Internet
Corporation for Assigned Names and Numbers (ICANN)
<https://www.icann.org/resources/pages/governance/governance-en>, a
global multi-stakeholder body with representation from end users,
governments, operators, and others.

Another example is the governance of the Web's trust model,
implemented by web browsers as relying parties that have strong
incentives to protect user privacy and security and CAs as trust
anchors that have a strong incentive to be included in browser trust
stores. To promote the operational and security requirements
necessary to provide the desired properties, the CA/Browser Forum
<https://cabforum.org> was established as an oversight body that
involves both parties as stakeholders.

These examples are notable in that the governance mechanism is not
specified in the protocol documents directly; rather, they are
layered on operationally, but in a manner that takes advantage of
protocol features that enable the imposition of governance.

Governance in this manner is suited to very limited functions like
the examples above. Even then, the setup and ongoing operation of a
governance mechanism is not trivial, and their legitimacy may be
difficult to establish and maintain (e.g., see [Palladino]); by their
nature, they are vulnerable to capture by the interests that are
being governed.

4. What Can Internet Standards Do?

Given the limits of decentralization techniques like federation and
distributed consensus, the voluntary nature of standards compliance,
and the powerful forces that can drive centralization, it is
reasonable to ask what standards efforts like those at the IETF can
do to accommodate helpful centralization while avoiding the
associated harms and acknowledging that the distinction itself is a
judgment call and, therefore, inherently political.

The subsections below suggest a few concrete, meaningful steps that
standards bodies can take.

4.1. Bolster Legitimacy

Where technical standards have only limited ability to control
centralization of the Internet, legal standards (whether regulation,
legislation, or case law) show more promise and are actively being
considered and implemented in various jurisdictions. However,
regulating the Internet is risky without a firm grounding in the
effects on the architecture informed by a technical viewpoint.

That viewpoint can and should be provided by the Internet standards
community. To effectively do so, its institutions must be seen as
legitimate by the relevant parties -- for example, competition
regulators. If the IETF is perceived as representing or being
controlled by "big tech" concerns or only US-based companies, its
ability to guide decisions that affect the Internet will be
diminished considerably.

The IETF already has features that arguably provide considerable
legitimacy. Examples of these features include open participation
and representation by individuals rather than by companies, both of
which enhance input legitimacy); a well-defined process with multiple
layers of appeals and transparency, which contributes to throughput
legitimacy; and a long history of successful Internet standards,
which provides perhaps the strongest source of legitimacy for the
IETF -- its output.

However, it is also widely recognized that the considerable costs
(not just financial) involved in successfully participating in the
IETF have a tendency to favor larger companies over smaller concerns.
Additionally, the specialized and highly technical nature of the work
creates barriers to entry for non-technical stakeholders. These
factors have the potential to reduce the legitimacy of the IETF's
decisions, at least in some eyes.

Efforts to address these shortcomings are ongoing; for example, see
[RFC8890]. Overall, bolstering the legitimacy of the organization
should be seen as a continuous effort.

When engaging in external efforts, the IETF community (especially its
leadership) should keep firmly in mind that its voice is most
authoritative when focused on technical and architectural impact.

4.2. Focus Discussion of Centralization

Centralization and decentralization are increasingly being raised in
technical standards discussions. Any claim needs to be critically
evaluated. As discussed in Section 2, not all centralization is
automatically harmful. Per Section 3, decentralization techniques do
not automatically address all centralization harms and may bring
their own risks.

However, standards participants rarely have the expertise or
information available to completely evaluate those claims, because
the analysis involves not only technical factors, but also economic,
social, commercial, and legal aspects. For example, economies of
scale can cause concentration due to the associated efficiencies
[Demsetz], and so determining whether that concentration is
appropriate requires a detailed economic analysis that is not in
scope for a technical standards body. Furthermore, claims of
centralization may have other motivations; in particular, they can be
proxies for power struggles between actors with competing interests,
and a claim of centralization might be used to deny market
participants and (perhaps more importantly) users the benefits of
standardization.

Therefore, approaches like requiring a "Centralization
Considerations" section in documents, gatekeeping publication on a
centralization review, or committing significant resources to
searching for centralization in protocols are unlikely to improve the
Internet.

Similarly, refusing to standardize a protocol because it does not
actively prevent all forms of centralization ignores the very limited
power that standards efforts have to do so. Almost all existing
Internet protocols -- including IP, TCP, HTTP, and DNS -- fail to
prevent centralized applications from using them. While the
imprimatur of the standards track [RFC2026] is not without value,
merely withholding it cannot prevent centralization.

Thus, discussions should be very focused and limited, and any
proposals for decentralization should be detailed so their full
effects can be evaluated. [Schneider1] implores those who propose
decentralization to be "really, really clear about what particular
features of a system a given design seeks to decentralize" and
promotes considered use of tools like separation of powers and
accountability from "old, institutional liberal political theory".

When evaluating claims that a given proposal is centralized, the
context of those statements should be examined for presuppositions,
assumptions, and omissions. [Bacchi] offers one framework for
critical interrogations, which can be adapted for centralization-
related discussions:

1. What is the nature of the centralization that is represented as
being problematic?

2. What deep-seated presuppositions or assumptions (conceptual
logics) underlie this representation of the "problem"?

3. How has this representation of the problem come about?

4. What is left unproblematic in this problem representation? Where
are the silences? Can the "problem" be conceptualized
differently?

5. What effects are produced by this representation of the
"problem"?

6. How and where has this representation of the "problem" been
produced, disseminated, and defended? How has it been and/or how
can it be disrupted and replaced?

4.3. Target Proprietary Functions

Functions that are widely used but lacking in interoperability are
ripe for standardization efforts. Targeting prominent and
proprietary functions (e.g., chat) is appropriate, but so are smaller
efforts to improve interoperability and portability of specific
features that are often used to lock users into a platform, for
example, a format for lists of contacts in a social network.

A common objection to this approach is that adoption is voluntary;
there are no "standards police" to mandate their use or enforce
correct implementation. For example, specifications like
[ACTIVITYSTREAMS] were available for some time without being used in
a federated manner by commercial social-networking providers.

That objection ignores the fact that while standards aren't
mandatory, legal regulation is. Legal mandates for interoperability
are increasingly proposed by policymakers as a remedy for competition
issues (e.g., see [DMA]). This appetite for regulation presents an
opportunity for new specifications to decentralize these functions,
backed by a legal mandate in combination with changing norms and the
resulting market forces [Lessig].

That opportunity also presents a risk, if the resulting legal
regulation is at odds with the Internet architecture. Successfully
creating standards that work in concert with legal regulation
presents many potential pitfalls and will require new and improved
capabilities (especially liaison) and considerable effort. If the
technical community does not make that effort, it is likely that
regulators will turn to other sources for interoperability
specifications.

4.4. Enable Switching

The ability to switch between different function providers is a core
mechanism to control centralization. If users are unable to switch,
they cannot exercise choice or fully realize the value of their
efforts because, for example, "learning to use a vendor's product
takes time, and the skill may not be fully transferable to a
competitor's product if there is inadequate standardization"
[FarrellJ].

Therefore, standards should have an explicit goal of facilitating
users switching between implementations and deployments of the
functions they define or enable.

One necessary condition for switching is the availability of
alternatives; breadth and diversity of implementation and deployment
are required. For example, if there is only a single implementation
of a protocol, applications that use it are vulnerable to the control
it has over their operation. Even open source projects can be an
issue in this regard if there are factors that make forking difficult
(for example, the cost of maintaining that fork). Section 2.1 of
[RFC5218] explores some factors in protocol design that encourage
diversity of implementation.

The cost of substituting an alternative implementation or deployment
by users is another important factor to consider. This includes
minimizing the amount of time, resources, expertise, coordination,
loss of functionality, and effort required to use a different
provider or implementation -- with the implication that the standard
needs to be functionally complete and specified precisely enough to
allow substitution.

These goals of completeness and diversity are sometimes at odds. If
a standard becomes extremely complex, it may discourage
implementation diversity because the cost of a complete
implementation is too high (consider web browsers). On the other
hand, if the specification is too simple, it may not enable easy
switching, especially if proprietary extensions are necessary to
complete it (see Section 4.7).

One objection to protocols that enable easy switching is that they
reduce the incentives for implementation by commercial vendors.
While a completely commoditized protocol might not allow
implementations to differentiate themselves, they provide
opportunities for specialization and improvement elsewhere in the
value chain [Christensen]. Well-timed standards efforts leverage
these forces to focus proprietary interests on top of open technology
rather than as a replacement for it.

4.5. Control Delegation of Power

The users of some functions might realize substantial benefits if
they are provided by a third party in communication. Adding a new
party to communication can improve the following:

* _Efficiency_: Many functions on the Internet are more efficient
when performed at a higher scale. For example, a content delivery
network can offer services at a fraction of the financial and
environmental cost that someone serving content themselves would
otherwise pay because of the scale they operate at. Likewise, a
two-sided market platform can introduce sizable efficiencies over
pair-wise buyer/seller trading [Spulber].

* _Simplicity_: Completely disintermediating communication can shift
the burden of functions onto endpoints. This can cause increased
cognitive load for users; for example, compare commercial social-
networking platforms with self-hosted efforts.

* _Specialization_: Having a function consolidated into a few hands
can improve outcomes because of the resulting specialization. For
example, services overseen by professional administrators are
often seen to have a better security posture and improved
availability.

* _Privacy_: For some functions, user privacy can be improved by
consolidating their activity to prevent individual behaviors from
being discriminated from each other [Chaum]. Introduction of a
third party can also enforce functional boundaries -- for example,
to reduce the need for users to trust potentially malicious
endpoints, as seen in the so-called "oblivious" protocols (e.g.,
[RFC9230]) that allow end users to hide their identity from
services while still accessing them.

However, if that new party is able to make their participation
"sticky" -- for example, by leveraging their position in the network
to require use of an intermediary, by exploiting their access to
data, or because it is difficult to switch to another provider of the
function -- there is a risk of centralization.

Most often, third parties are added to functions as "intermediaries"
or in designated "agent" roles. Designing such functions with
thoughtful constraints on these roles can prevent at least the most
egregious abuses of such power.

When adding new parties to a function, two guidelines have proven
useful. First, third parties should only be interposed into
communication when at least one of the primary parties takes a
positive action to do so. Second, third parties should have their
ability to observe or control communication limited to what is
necessary to perform their intended function.

For example, early deployments of HTTP allowed intermediaries to be
interposed by the network without knowledge of the endpoints, and
those intermediaries could see and change the full content of traffic
by default -- even when they were only intended to perform basic
functions such as caching. Because of the introduction of HTTPS and
the CONNECT method (see Section 9.3.6 of [HTTP]), combined with
efforts to encourage its adoption, those intermediaries are now
required to be explicitly interposed by one endpoint, and they only
have access to basic routing information.

See [THOMSON-TMI] for more guidance on protocol intermediation.

The term "intermediary" is also used (often in legal and regulatory
contexts) more broadly than it has been in protocol design; for
example, an auction website that intermediates between buyers and
sellers is considered an intermediary, even though it is not formally
an intermediary in HTTP (see Section 3.7 of [HTTP]). Protocol
designers can address the centralization associated with this kind of
intermediation by standardizing the function rather than restricting
the capabilities of the underlying protocols; see Section 4.3.

4.6. Enforce Boundaries

Most Internet protocols and applications depend on other, "lower-
layer" functions and their implementations. The features,
deployment, and operation of these dependencies can become
centralization risks for the functions and applications built "on
top" of them.

For example, application protocols require a network to function;
therefore, a degree of power over communication is available to the
network provider. They might block access to, slow down, or change
the content of a specific service for financial, political,
operational, or criminal reasons, creating a disincentive (or even
removing the ability) to use a specific provider of a function. By
selectively hindering the use of some services but not others,
network interventions can be composed to create pressure to use those
other services -- intentionally or not.

Techniques like encryption can discourage such centralization by
enforcing such boundaries. When the number of parties who have
access to the content of communication is limited, other parties who
handle it but are not party to it can be prevented from interfering
with and observing it. Although those parties might still prevent
communication, encryption also makes it more difficult to
discriminate a target from other users' traffic.

4.7. Consider Extensibility Carefully

The Internet's ability to evolve is critical, allowing it to meet new
requirements and adapt to new conditions without requiring a "flag
day" to upgrade implementations. Typically, functions accommodate
evolution by defining extension interfaces, which allow optional
features to be added or change over time in an interoperable fashion.

However, these interfaces can also be leveraged by a powerful entity
if they can change the target for meaningful interoperability by
adding proprietary extensions to a standard. This is especially true
when the core standard does not itself provide sufficient utility on
its own.

For example, the extreme flexibility of SOAP [SOAP] and its failure
to provide significant standalone value allowed vendors to require
use of their preferred extensions, favoring those who had more market
power.

Therefore, standards efforts should focus on providing concrete
utility to the majority of their users as published, rather than
being a "framework" where interoperability is not immediately
available. Internet functions should not make every aspect of their
operation extensible; boundaries between modules should be designed
in a way that allows evolution, while still offering meaningful
functionality.

Beyond allowing evolution, well-considered interfaces can also aid
decentralization efforts. The structural boundaries that emerge
between the sub-modules of the function -- as well as those with
adjacent functions -- provide touchpoints for interoperability and an
opportunity for substitution of providers.

In particular, if the interfaces of a function are well-defined and
stable, there is an opportunity to use different providers for that
function. When those interfaces are open standards, change control
resides with the technical community instead of remaining in
proprietary hands, further enhancing stability and enabling (but not
ensuring) decentralization.

4.8. Reuse What Works

When centralization is purposefully allowed in an Internet function,
protocol designers often attempt to mitigate the associated risks
using technical measures such as federation (see Section 3.1.1) and
operational governance structures (see Section 3.1.3).

Protocols that successfully do so are often reused to avoid the
considerable cost and risk of reimplementing those mitigations. For
example, if a protocol requires a coordinated global naming function,
incorporating the Domain Name System is usually preferable to
establishing a new system.

5. Future Work

This document has argued that, while standards bodies have little
means of effectively controlling or preventing centralization of the
Internet through protocol design, there are still concrete and useful
steps they can take to improve the Internet.

Those steps might be elaborated upon and extended in future work;
however, it is doubtless there is more that can be done. New
decentralization techniques might be identified and examined; what we
learn from relationships with other, more effective regulators in
this space can be documented.

Some have suggested creating a how-to guide or checklist for dealing
with centralization. Because centralization is so contextual and so
varied in how it manifests, this might best be attempted within very
limited areas -- for example, for a particular type of function or a
function at a particular layer.

The nature of centralization also deserves further study; in
particular, its causes. While there is much commentary on factors
like network effects and switching costs, other aspects -- such as
behavioral, cognitive, social, and economic factors have received
comparatively little attention, although that is changing (e.g.,
[Fletcher]).

6. Security Considerations

This document does not have a direct security impact on Internet
protocols. That said, failure to consider centralization might cause
a myriad of security issues; see Section 2.1 for a preliminary
discussion.

7. IANA Considerations

This document has no IANA actions.

8. Informative References

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Abrahamson, Z., "Essential Data", Yale Law Journal, Vol.
124, No. 3, December 2014,
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[ACTIVITYSTREAMS]
Prodromou, E., Ed. and J. Snell, Ed., "Activity Streams
2.0", W3C Recommendation, 23 May 2017,
<https://www.w3.org/TR/2017/REC-activitystreams-core-
20170523/>. Latest version available at
<https://www.w3.org/TR/ activitystreams-core/>.

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Ostrom, and Beyond", Governance: An International Journal
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2, p. 237, DOI 10.1111/j.1468-0491.2011.01550.x, April
2012, <https://onlinelibrary.wiley.com/doi/abs/10.1111/
j.1468-0491.2011.01550.x>.

[Bacchi] Bacchi, C., "Introducing the 'What's the Problem
Represented to be?' approach", Chapter 2, Engaging with
Carol Bacchi, 2012, <https://library.oapen.org/bitstream/
handle/20.500.12657/33181/560097.pdf?sequence=1#page=34>.

[Baran] Baran, P., "On Distributed Communications: Introduction to
Distributed Communications Networks", DOI 10.7249/RM3420,
1964, <https://www.rand.org/pubs/research_memoranda/
RM3420.html>.

[BCP95] Alvestrand, H., "A Mission Statement for the IETF",
BCP 95, RFC 3935, October 2004.

<https://www.rfc-editor.org/info/bcp95>

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"Decentralization: a multidisciplinary perspective",
Internet Policy Review, Vol. 10, No. 2,
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and digital pseudonyms", Communications of the ACM, Vol.
24, No. 2, DOI 10.1145/358549.358563, February 1981,
<https://dl.acm.org/doi/10.1145/358549.358563>.

[Christensen]
Christensen, C., "The Law of Conservation of Attractive
Profits", Harvard Business Review, "Breakthrough Ideas for
2004", February 2004.

[Demsetz] Demsetz, H., "Industry Structure, Market Rivalry, and
Public Policy", Journal of Law and Economics, Vol. 16, No.
1, April 1973, <https://www.jstor.org/stable/724822>.

[DMA] The European Parliament and the Council of the European
Union, "Regulation (EU) 2022/1925 of the European
Parliament and of the Council of 14 September 2022 on
contestable and fair markets in the digital sector and
amending Directives (EU) 2019/1937 and (EU) 2020/1828
(Digital Markets Act)", OJ L 265/1, 12.10.2022, September
2022, <https://eur-lex.europa.eu/legal-content/EN/
TXT/?uri=CELEX%3A32022R1925>.

[Doctorow] Doctorow, C., "Adversarial Interoperability", October
2019, <https://www.eff.org/deeplinks/2019/10/adversarial-
interoperability>.

[ETHEREUM] Ethereum, "The Merge", February 2023,
<https://ethereum.org/en/roadmap/merge/>.

[FarrellH] Farrell, H. and A. Newman, "Weaponized Interdependence:
How Global Economic Networks Shape State Coercion",
International Security, Vol. 44, No. 1, p. 42,
DOI 10.1162/ISEC_a_00351, July 2019,
<https://doi.org/10.1162/ISEC_a_00351>.

[FarrellJ] Farrell, J. and C. Shapiro, "Dynamic Competition with
Switching Costs", UC Berkeley Department of Economics
Working Paper 8865, DOI 10.2307/2555402, January 1988,
<https://doi.org/10.2307/2555402>.

[Fletcher] Fletcher, A., "The Role of Behavioural Economics in
Competition Policy", DOI 10.2139/ssrn.4389681, March 2023,
<https://doi.org/10.2139/ssrn.4389681>.

[Freeman] Freeman, J., "The Tyranny of Structurelessness", Berkeley
Journal of Sociology, Vol. 17, 1972,
<https://www.jstor.org/stable/41035187>.

[Holzbauer]
Holzbauer, F., Ullrich, J., Lindorfer, M., and T. Fiebig,
"Not that Simple: Email Delivery in the 21st Century",
July 2022,
<https://www.usenix.org/system/files/atc22-holzbauer.pdf>.

[HTTP] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", STD 97, RFC 9110,
DOI 10.17487/RFC9110, June 2022,
<https://www.rfc-editor.org/info/rfc9110>.

[Kashaf] Kashaf, A., Sekar, V., and Y. Agarwal, "Analyzing Third
Party Service Dependencies in Modern Web Services: Have We
Learned from the Mirai-Dyn Incident?",
DOI 10.1145/3419394.3423664, October 2020,
<https://dl.acm.org/doi/pdf/10.1145/3419394.3423664>.

[Komaitis] Komaitis, K., "Regulators Seem to Think That Facebook Is
the Internet", August 2021,
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regulation.html>.

[Lessig] Lessig, L., "The New Chicago School", Journal of Legal
Studies, Vol. 27, DOI 10.1086/468039, June 1998,
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[Madison] Madison, J., "The Structure of the Government Must Furnish
the Proper Checks and Balances Between the Different
Departments", The Federalist Papers, No. 51, February
1788.

[Makarov] Makarov, I. and A. Schoar, "Blockchain Analysis of the
Bitcoin Market", National Bureau of Economic Research,
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<https://www.nber.org/papers/w29396>.

[Marlinspike]
Marlinspike, M., "Reflections: The ecosystem is moving",
May 2016,
<https://signal.org/blog/the-ecosystem-is-moving/>.

[Moura] Moura, G., Castro, S., Hardaker, W., Wullink, M., and C.
Hesselman, "Clouding up the Internet: how centralized is
DNS traffic becoming?", DOI 10.1145/3419394.3423625,
October 2020,
<https://dl.acm.org/doi/abs/10.1145/3419394.3423625>.

[Musiani] Musiani, F., "Alternative Technologies as Alternative
Institutions: The Case of the Domain Name System", The
Turn to Infrastructure in Internet Governance,
DOI 10.1057/9781137483591_4, 2016,
<https://link.springer.com/
chapter/10.1057/9781137483591_4>.

[Palladino]
Palladino, N. and M. Santaniello, "Legitimacy, Power, and
Inequalities in the Multistakeholder Internet Governance",
DOI 10.1007/978-3-030-56131-4, November 2020,
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book/10.1007/978-3-030-56131-4>.

[PHONE] Skrzycki, C. and J. Burgess, "Computer Failure Paralyzes
Region's Phone Service", June 1991,
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politics/1991/06/27/computer-failure-paralyzes-regions-
phone-service/0db94ac7-89f0-446e-ba33-c126c751b251/>.

[RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, DOI 10.17487/RFC2026, October 1996,
<https://www.rfc-editor.org/info/rfc2026>.

[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.

[RFC5218] Thaler, D. and B. Aboba, "What Makes for a Successful
Protocol?", RFC 5218, DOI 10.17487/RFC5218, July 2008,
<https://www.rfc-editor.org/info/rfc5218>.

[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
DOI 10.17487/RFC5321, October 2008,
<https://www.rfc-editor.org/info/rfc5321>.

[RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Core", RFC 6120, DOI 10.17487/RFC6120,
March 2011, <https://www.rfc-editor.org/info/rfc6120>.

[RFC791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.

[RFC8890] Nottingham, M., "The Internet is for End Users", RFC 8890,
DOI 10.17487/RFC8890, August 2020,
<https://www.rfc-editor.org/info/rfc8890>.

[RFC9230] Kinnear, E., McManus, P., Pauly, T., Verma, T., and C.A.
Wood, "Oblivious DNS over HTTPS", RFC 9230,
DOI 10.17487/RFC9230, June 2022,
<https://www.rfc-editor.org/info/rfc9230>.

[RFC9293] Eddy, W., Ed., "Transmission Control Protocol (TCP)",
STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
<https://www.rfc-editor.org/info/rfc9293>.

[Schneider1]
Schneider, N., "What to do once you admit that
decentralizing everything never seems to work", Hacker
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soap12-part0/>.

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[THOMSON-TMI]
Thomson, M., "Principles for the Involvement of
Intermediaries in Internet Protocols", Work in Progress,
Internet-Draft, draft-thomson-tmi-04, 8 September 2022,
<https://datatracker.ietf.org/doc/html/draft-thomson-tmi-
04>.

Acknowledgements

This document was born out of early discussions with Brian Trammell
during our shared time on the Internet Architecture Board.

Special thanks to Geoff Huston and Milton Mueller for their well-
considered, thoughtful, and helpful reviews.

Thanks to Jari Arkko, Kristin Berdan, Richard Clayton, Cory Doctorow,
Christian Huitema, Eliot Lear, John Levine, Tommy Pauly, and Martin
Thomson for their comments and suggestions. Likewise, the arch-
[email protected] (mailto:[email protected]) mailing list and
Decentralized Internet Infrastructure Research Group provided
valuable discussion and feedback.

No large language models were used in the production of this
document.

Author's Address

Mark Nottingham
Prahran
Australia
Email: [email protected]
URI: https://www.mnot.net/