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Prahran Australia mnot@mnot.net https://www.mnot.net/

General governance Despite the Internet being designed and operated as a decentralized network-of-networks, forces that encourage consolidation of power over its functions into few hands continuously emerge. This document discusses centralization in Internet protocols and relates it to consolidation of power, explains why both are undesirable, identifies forces that contribute to them, catalogues limitations of common approaches to decentralization, and explores what Internet standards efforts can do. About This Document Status information for this document may be found at . Source for this draft and an issue tracker can be found at .

Introduction The Internet has succeeded in no small part because of its purposeful avoidance of any single controlling entity. While originating in a desire to prevent a single technical failure from having a wide impact , this stance has also enabled the Internet’s rapid adoption and broad spread. The Internet can accommodate a spectrum of requirements and is now a global public good because permission is not required to connect to it, deploy an application on it, or use it for a particular purpose. While maintaining these properties remains a widely shared goal for the Internet, consistently achieving them has proven more difficult over time. Today, many successful Internet services operate in a centralized fashion -- to the point where some proprietary applications have become so well-known that they are commonly mistaken for the Internet itself. Even when open protocols incorporate techniques intended to prevent consolidation, economic and social factors can drive users to prefer solutions built with or on top of supposedly decentralized technology. These difficulties call into question what role architectural design -- in particular, that overseen by open standards bodies such as the IETF -- should play in preventing, mitigating, and controlling consolidation of power on the Internet. This document discusses aspects of centralization that relate to Internet standards efforts, and argues that while the IETF may not be able to prevent these outcomes, there are still meaningful steps it can take to help counteract them. defines centralization and consolidation, explains why and when they are undesirable, and surveys how they occur on the Internet. explores decentralization and highlights some relevant techniques, along with their limitations. Finally, considers the role that Internet standards play in avoiding centralization and mitigating its effects. The primary audience for this document is the engineers who design and standardize Internet protocols. However, designers of proprietary protocols and applications can benefit from considering these issues, especially if they intend their work to be considered for eventual standardization. Likewise, policymakers can use this document to help identify and evaluate proposed remedies for inappropriately centralized protocols and applications.

Centralization and Consolidation This document distinguishes "consolidation" from "centralization" to separate effects from (some of) their causes. "Consolidation" is the ability of a single entity or a small group of them to exclusively observe, capture, control, or extract rent from the operation or use of an Internet function. Here, "entity" could be a single person, a corporation, or a government. It does not include an organization that operates in a manner that effectively mitigates consolidation (see, e.g., ). "Internet function" is used broadly in this document. It might be an enabling protocol already defined by standards, such as IP , BGP , TCP , or HTTP . It might also be a proposal for a new enabling protocol, or an extension to an existing one. Furthermore, Internet functions are not limited to standards-defined protocols. User-visible applications built on top of standard protocols are also vulnerable to consolidation -- for example, social networking, file sharing, financial services, and news dissemination. Likewise, networking equipment, hardware, operating systems, and software act as enabling technologies that can exhibit consolidation. The supply of Internet connectivity to end users in a particular area or situation can also be subject to consolidation, as can the supply of transit between networks (so called "Tier 1" networks). "Centralization" is the source of consolidation that this document focuses upon; it measures the direct or potential contribution of a function's technical design to consolidation. For example, many consider the social networking market to be highly consolidated around a few providers who have used highly centralized architectures (see ) to reinforce their control. Centralization is not a binary condition; a function's design might contribute to or be vulnerable to consolidation in multiple ways and in various degrees. Even when decentralization techniques are purposefully used to avoid centralization in a particular aspect of a function, it often appears in other places -- for example, in its governance, implementation, deployment, or in ancillary functions. In summary, "decentralized technology alone does not guarantee decentralized outcomes."

Assessing Centralization By default, Internet protocol designers will avoid an obviously centralized design because the Internet's very nature is incompatible with it. As a "large, heterogeneous collection of interconnected systems" the Internet is often characterised as a "network of networks". These networks relate as peers who agree to facilitate communication, rather than having a relationship of subservience to others' requirements or coercion by them. This focus on independence of action carries through the way the network is architected -- for example, in the concept of an "autonomous system". However, as discussed below in , not all centralization is avoidable, and in some cases, it is even desirable. With that in mind, centralization on the Internet is most concerning when it is not broadly held to be necessary, when it has no checks, balances, or other mechanisms of accountability, when it selects "favorites" which are difficult (or impossible) to displace, and when it threatens to diminish the success factors that enable the Internet to thrive -- scalability to meet the demands of new users, adaptability to encompass new applications, flexibility to enable deployment of new technologies, and resilience to shocks and changes . Most often, unacceptable centralization is indicated when a proposal has one or more of the following damaging effects (or the potential for them):

• Power Imbalance: When a third party has unavoidable access to communications, the informational and positional advantages gained 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 or even to disrupt society itself. Just as good governance of states requires separation of powers , so too does good governance of the Internet require that power not be concentrated in one place without appropriate checks and balances.
• Limits on Innovation: Consolidation can preclude the possibility of "permissionless innovation" -- 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 consolidated service or platform must be used because no substitutes are suitable, it effectively becomes an essential facility, which encourages 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 consolidated provider, that provider's failure can have a disproportionate impact on availability.
• Monoculture: The scale available to a consolidated 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' implementation 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."
• Self-Reinforcement: As widely noted (see, e.g., ), a consolidated provider's access to data allows it the opportunity to make improvements to its offerings, while denying such access to others.

However, these are only indicators, and each needs to be evaluated carefully on a case-by-case basis. For example, it is important to distinguish centralization from anticompetitive concerns (also known as "antitrust"). While there are many interactions between these concepts and making the Internet more competitive may be a motivation for avoiding consolidation, only courts (and sometimes, regulators) have the authority to define a relevant market and determine that behavior is anti-competitive. Furthermore, what might be considered undesirable consolidation by the technical community might not attract competition regulation. Conversely, what might attract competition regulation might not be of great concern to the technical community if other mitigations are felt to be adequate. Likewise, while centralization interacts with availability, they are distinct and any relationship between them cannot be assumed without careful analysis of where and how centralization occurs. Centralized systems might be more available because of factors like the resources available to them, but also have greater impact when they encounter a fault; decentralized systems might be more resilient in the face of local failures, but less able to react to systemic issues. A failure because of a cut cable, power outage, or failed server is qualitatively different from the issues encountered when a core Internet function has a gatekeeper. For example, a large variety of Web sites might depend upon a cloud hosting provider or content delivery network; if it were to become unavailable (whether for technical or other reasons), many people's experience of the Internet might be disrupted. Likewise, a mobile Internet access provider might have an outage that affects hundreds, thousands, or more of its users. In both cases, centralization is not indicated by the loss of availability or its scale, but it well might be if the parties relying on the function don't have reasonable options to switch to if they are unhappy with the availability of the service provided, or if friction against switching to an alternative is too great.

How Centralization Occurs A function's design can exhibit and encourage centralization in a variety of ways. The subsections below describe different contributors to and expressions of centralization in Internet functions. Note that this is not a taxonomy, in that it is not complete and there may be overlap.

Proprietary Centralization Creating of a protocol or application with a fixed role for a specific party is the most obvious form of centralization. Many messaging, videoconferencing, chat, social networking, and similar applications currently operate in this fashion. Because they allow control by a single entity, proprietary protocols are often considered simpler to design, more amenable to evolution, and more likely to meet user needs , compared to decentralized alternatives. However, their centralization is absolute -- if the function has no alternative providers, or switching to those providers is too difficult, its users are "locked in." Proprietary protocols and applications are not considered as being part of the Internet per se; instead, they are more properly characterized as being built on top of the Internet. The Internet architecture and associated standards do not control them, beyond the constraints that the underlying protocols (e.g., TCP, IP, HTTP) impose.

Beneficial Centralization Some protocols and applications have goals that require centralization, because they rely on it to deliver a particular benefit. Often, this is due to technical necessity. For example, a single, globally coordinated “source of truth” is by nature centralized -- such as in the Domain Name System (DNS), which allows human-friendly naming to be converted into network addresses in a globally consistent fashion. Or, consider IP addresses 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. The same benefits and risks can be seen in the Web's trust model, thanks to the Certificate Authority's role in communication between clients and servers Protocols that need to solve the "rendezvous problem" to coordinate communication between two parties who are not in direct contact also exhibit beneficial 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 is centralized. Even when not strictly necessary, centralization can be deployed to beneficial ends. 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." For example, when traffic from many users is mixed in a way that can't be distinguished, censorship becomes more difficult. This "too big to block" phenomenon drives the design of many recent protocols (such as ), but they require a degree of centralization to meet their goals. Likewise, when a function requires governance to realize common goals and protect minority interests, a "choke point" is naturally formed by the chosen governance mechanism, increasing centralization. For example, content moderation functions concentrate decision making to impose community values. Complex and risky functions like financial services (e.g., credit card processing) can be seen as beneficially centralized into relatively few, specialized organizations, where they can received the focused attention that they require. When beneficial centralization is present, Internet protocols often attempt to mitigate the associated risks using measures such as federation (see ) or multi-stakeholder governance (see ). Protocols that successfully do so are often reused to avoid the considerable cost and risk of re-implementing those mitigations. For example, if a protocol requires a coordinated, global naming function, reusing the Domain Name System is usually preferable to establishing a new system. Ultimately, deciding what is beneficial is a judgment call. Some protocols cannot function without a centralized function; others might be significantly enhanced for certain use cases if a function is centralized, or might merely be more efficient. Such judgments should be made in light of established architectural principles and how benefits accrue to end users.

Concentration Even when a function avoids or mitigates other forms of centralization, it might become consolidated in practice when external factors influence its deployment, so that few or even just one entity provides the function. This document refers to this phenomenon as "concentration." Concentration can be caused by economic, legal, social, and even cognitive factors that encourage use of a central function despite the absence of such a requirement in the protocol itself. Concentration is often associated with the network effects that are so often seen on the Internet. While in theory every node on the Internet is equal, in practice some nodes are much more connected than others: for example, just a few sites drive much of the traffic on the Web. While expected and observed in many kinds of networks, these effects award asymmetric power to nodes that act as intermediaries to communication. There may be legitimate qualitative reasons for some nodes being favoured over others. However, when it happens because friction against using an alternative prevents switching, benefits are accrued to services rather than users. If choosing an alternate provider requires a significant amount of time, resources, expertise, coordination, loss of functionality, or effort, centralization is indicated. Conversely, a function based on a well-defined, open specification designed to minimize switching costs might be considered to have less centralization even when users continue to favor large providers, because ease of switching creates implicit competitive pressure upon them. For example, social networking is an application that is currently supplied by a few proprietary platforms despite standardization efforts (see, e.g., ), because of the powerful network effects associated. While there has been some competition in social networking, the choices that their peers make often restricts individual choices, because of the coordination required to move to a new service. See for a deeper exploration of concentration. Concentration is difficult to avoid in protocol design, and federated protocols are particularly vulnerable to it (see ).

Inherited Centralization Most Internet protocols and applications depend on other, "lower-layer" functions and their implementations. The features, deployment, and operation of these dependencies can surface centralization into functions and applications built "on top" of them. For example, the network between endpoints can introduce this kind of centralization to application-layer protocols because it is necessary for communication and therefore has power over it. A network might block access to, slow down, or change the content of various application protocols or specific services for financial, political, operational, or criminal reasons, thereby creating a disincentive (or even removing the ability) to use them. By selectively hindering the use of some services but not others, network interventions can be composed to aid concentration in those other services -- intentionally or not. Likewise, having only a single implementation of a protocol is a form of inherited centralization, because applications that use it are vulnerable to the control it has over their operation. Even Open Source projects can exhibit this if there are factors that make forking difficult (for example, the cost of maintaining that fork). Inherited centralization surfaces when viable alternatives to these dependencies are not available. It is often present when network effects restrict choices, but can also be created by legal mandates and incentives that restrict the options for a function (such as Internet access), its provision, or the range of implementations available. Alternatively, it might occur due to scarcity. For example, the exhaustion of IPv4 addresses creates a power differential between those who have addresses and those who do not, which can affect how the protocols that depend on IP connectivity are deployed and used. If those addresses are held by only a few consolidation is the result, in turn leading to ossification because new applications cannot be deployed without their cooperation. Some effects of inherited centralization can be mitigated by enforcing layer boundaries using techniques like encryption. When the number of parties who have access to content of communication are limited, parties at lower layers can be prevented from interfering with and observing it. Although those lower-layer parties might still prevent communication, encryption also makes it more difficult to discriminate a target from other users' traffic. Note that the prohibitive effect of encryption on inherited centralization is most pronounced when most (if not all) traffic is encrypted. See also .

Platform Centralization The complement to inherited centralization is platform centralization -- where a function does not directly define a central role, but could facilitate consolidation in the applications it supports. For example, HTTP is not generally considered a centralized protocol; interoperable servers are easy to instantiate, and multiple clients are available. It can be used without central coordination beyond that provided by DNS, as discussed above. However, applications built on top of HTTP (as well as the rest of the “Web Platform”) often exhibit consolidation (for example, social networking). HTTP is therefore an example of platform centralization -- while the protocol itself is not centralized, it facilitates the creation of consolidated services and applications. Like concentration, platform centralization is difficult to prevent with protocol design. Because of the layered nature of the Internet, most protocols allow considerable flexibility in how they are used, to promote permissionless innovation.

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." This seemingly straightforward technical definition hides several issues. First, identifying which aspects of a function to decentralize and how to do so can be difficult, both because there are often many ways a function might be centralized, and because consolidation sometimes only becomes clear after the function is deployed at scale. Efforts to decentralize often have the effect of merely shifting consolidation to a different place. For example, a cloud storage function might be implemented using a distributed consensus protocol, assuring that the failure of any single node will not affect the system's operation or availability. In that sense, it is decentralized. However, if it is operated by a single legal entity, that brings a very different kind of centralization, especially if there are few other options available, or if there is friction against choosing other options. Another example is the Web, which was envisioned and widely held to be a decentralizing force in its early life. Its inherent platform centralization only became apparent when large sites successfully leveraged network effects for dominance of social networking, marketplaces, and similar functions. Second, 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 one what the "right" level or type is, how to weigh different forms of centralization against each other, or how to weigh potential consolidation against other architectural goals (such as security or privacy). These tensions can be seen, for example, in the DNS. While much of the system is decentralized through the distribution of the lookup function to local servers that users have the option to override, the DNS is also 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 ). 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 multistakeholderism. Third, decentralization unavoidably involves adjustments to the power relationships between protocol participants, especially when it opens up the possibility of consolidation elsewhere. As Schneider notes in , 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, as more bluntly stated in , "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." For example, while blockchain-based cryptocurrencies might address the consolidation inherent in traditional currencies through technical means, the concentration of power that many exhibit in terms of voting/mining power, distribution of funds, and diversity of codebase causes some to question how decentralized they actually are. The lack of formal structures brings an opportunity for latent, informal power structures that have their own risks -- including consolidation. In practice, this means that decentralizing a function requires considerable work, is inherently political, and involves a large degree of uncertainty about the outcome. In particular, 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."

Decentralization Techniques Over time, a few different techniques have been used to facilitate decentralization of Internet protocols. The subsection below examine some of these techniques, along with their limitations. None of them is a panacea; it is not possible to completely remove all forms of centralization from protocols that, at their heart, require agreement between multiple parties. However, when performed properly, decentralization might produce an outcome where that risk is understood, acceptable, and, where possible and appropriate, mitigated. There is also no "correct" way to decentralize; it does not require that provision of a function need be distributed in a particular fashion, or to a particular degree. For example, the Domain Name System is widely agreed to have an acceptable form of centralization, despite it being provided by a limited set of entities.

Federation A common technique for addressing centralization in Internet protocols is federation -- designing them in such a way that new instances of a function are easy to create and can maintain interoperability and connectivity with other instances. For example, SMTP is the basis of the e-mail suite of protocols, which has two functions that exhibit centralization:

1. Giving each user a globally unique address, and
2. Routing messages to the user, even when they change network locations or become disconnected for long periods of time.

E-mail reuses DNS to help mitigate the first. To mitigate the second, it 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's users avoid a requirement for a single central router. Users can (and often do) choose to delegate that role to someone else, or run their own MTA. However, many now consider running a personal MTA to be impractical because of the likelihood of a small MTA being classified as a spam source. Because large MTA operators are widely known and have greater impact if their operation is affected, they are less likely to be classified as such, concentrating the protocol’s operation (see ). Another example of a federated Internet protocol is XMPP , supporting "instant messaging" and similar functionality. Like e-mail, it reuses DNS for naming and requires federation to facilitate rendezvous of users from different systems. While some deployments of XMPP 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, denying them the benefits of global interoperability. The examples above illustrate that, while federation can be a useful technique for avoiding proprietary centralization and managing beneficial centralization, it does not prevent concentration or platform centralization. If a single entity can capture the value provided by a protocol, it may use the protocol as a platform to get a “winner take all” outcome -- a significant risk with many Internet protocols, since network effects often promote such outcomes. Likewise, external factors (such as spam control) might naturally “tilt the table” towards a few operators.

Multi-Stakeholder Governance Protocol designers sometime attempt to mitigate beneficial centralization (see ) by delegating that function's governance to a multi-stakeholder body -- 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. The most widely studied example of this technique is the governance of the DNS name space, which as a “single source of truth” exhibits beneficial centralization. The associated risk is managed through administration by the Internet Corporation for Assigned Names and Numbers (ICANN), 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 and Certificate Authorities as trust anchors. To promote the operational and security requirements necessary to provide the desired properties, the CA/Browser Forum was established as an oversight body that involves both parties as stakeholders. Yet another example of multi-stakeholderism is the standardization of Internet protocols themselves. Because a specification controls implementation behavior, the standardization process can be seen as a single point of control. As a result, Internet standards bodies like the IETF allow open participation and contribution, make decisions in an open and accountable way, have a well-defined process for making (and when necessary, appealing) decisions, considering the views of different stakeholder groups . A major downside of this approach is that setup and ongoing operation of multi-stakeholder bodies is not trivial. Additionally, their legitimacy cannot be assumed, and may be difficult to establish and maintain (see, e.g., ). This concern is especially relevant if the function being coordinated is broad, complex, and/or contentious.

Distributed Consensus Increasingly, distributed consensus technologies (such as the blockchain) are touted as a solution to consolidation issues. A complete survey of this rapidly changing area is beyond the scope of this document, but we can generalize about its properties. These techniques attempt to avoid centralization by distributing functions to members of a sometimes large pool of protocol participants. They typically guarantee proper performance of a function using cryptographic techniques (often, an append-only transaction ledger). A particular task's assignment to a node for handling usually 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. They encourage diversity in the pool of participants using indirect techniques, such as proof-of-work (where each participant has to show significant consumption of resources) or proof-of-stake (where each participant has some other incentive to execute correctly). Use of these techniques can create barriers to proprietary and inherited centralization. However, depending upon the application in question, both concentration and platform centralization are still possible. Furthermore, a protocol or an application can use distributed consensus for some functions, but still be centralized elsewhere -- either because those functions cannot be decentralized (most commonly, rendezvous and global naming; see ) or because the designer has chosen not to because of the associated costs and lost opportunities. Even when distributed consensus is used for all technical functions of a service, some coordination is still necessary -- whether that be through governance of the function itself, creation of shared implementations, or documentation of shared wire protocols. That represents centralization, just at a different layer (inherited or platform). For example, the Ethereum "merge" demonstrated that the blockchain could address environmental concerns, but only through coordinated community effort and governance. These potential shortcomings do not rule out the use of distributed consensus technologies in every instance. They do, however, caution against uncritically relying upon these technologies to avoid or mitigate centralization.

What Should Internet Standards Do? Centralization is driven by powerful forces -- both economic and social -- as well as the network effects that come with Internet scale. Bodies like the IETF create voluntary standards; they cannot require adoption, but when a specification succeeds it creates those very network effects. As such, standards bodies cannot prevent all forms of consolidation, but they can still take meaningful steps to prevent some of them. The subsections below suggest a few.

Bolster Legitimacy Many efforts to address Internet consolidation are likely to take place outside of standards bodies. If the IETF wishes to contribute to these efforts and assure their compatibility with the Internet's architectural goals, it must be seen as legitimate by the relevant parties -- especially, by competition regulators. Otherwise, if the IETF is perceived as representing or being controlled by "big tech" concerns, its ability to guide decisions that affect the Internet will be diminished considerably. The IETF already has features that arguably provide considerable legitimacy; for example, open participation and representation by individuals rather than companies both enhance input legitimacy; a well-defined process with multiple layers of appeals and transparency contributes to throughput legitimacy, and a long history of successful Internet standards provides perhaps the strongest source of legitimacy for the IETF -- its output. However, it is also widely recognized the considerable costs (not just financial) involved in successfully participating in the IETF have a tendency to favour larger companies over smaller concerns. Likewise, the specialised 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; see, for example, . Overall, bolstering the legitimacy of the organization should be seen as a continuous effort.

Engage with Centralization Thoroughly but Realistically Some kinds of centralization are easy to manage in standards efforts. For example, if a protocol with a fixed role for a single party were to be proposed to the IETF for publication as a standard, it would be rejected out of hand. There is a growing body of knowledge and experience in managing the risks of beneficial centralization, and a strong inclination to reuse existing infrastructure where possible. As discussed above, encryption is often a way to manage inherited centralization, and has become the norm in standard protocols. These responses are appropriate ways for Internet standards to manage centralization. However, mitigating concentration and platform centralization is much more difficult in standards efforts. Because the IETF has no "protocol police", it’s not possible to demand, for example, that someone stop building a proprietary service using a federated protocol; even if it could, doing so would contradict architectural goals like permissionless innovation. While the imprimatur of an Internet Standard is not without value, merely withholding it cannot prevent these sources of consolidation. Therefore, committing significant resources to scrutinizing protocols for latent centralization -- especially for concentration and platform centralization -- is unlikely to be effective in preventing Internet consolidation. Almost all existing Internet protocols -- including IP, TCP, HTTP, and DNS -- exhibit concentration or platform centralization. Refusing to standardize a newer protocol because it exhibits similar properties would not be equitable, proportionate, or effective. When claims are made that a given proposal is "centralized" or "decentralized", the context of those statements should be examined for presuppositions, assumptions, and omissions. offers one framework for such critical interrogations. implores that proposals to decentralize be "really, really clear about what particular features of a system a given design seeks to decentralize" and promotes borrowing remedies from more traditional governance systems, such as separation of powers and accountability. When centralization is found, standards efforts should consider its relationship with architectural goals as they consider how to address it. In particular, attention should be paid to how effective standards (as a form of architectural control) is in achieving each goal. For example, privacy is often more effectively ensured by ex ante technical constraints, as compared to ex post legal regulation. Conversely (as discussed) some centralization may be more effectively addressed through legal regulation. Thus, a standards effort balancing these concerns might focus primarily on privacy. However, these are often not completely separable goals. Concentration can result in one or a few entities having greater volume and variety of data available exclusively to them, raising significant privacy and security concerns.

Decentralize Proprietary Functions It is worthwhile to create specifications for functions that are currently only available from proprietary providers. Open standards can provide a viable alternative to a consolidated function. Such efforts might include large-scale protocols for existing proprietary functions (e.g., chat) as well as smaller efforts to improve interoperability and portability of specific features that are often used to "lock in" users to 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, not mandatory; there are no "standards police" to mandate their use or enforce correct implementation. For example, specifications like ) have been available for some time without being used in a federated manner by commercial social networking providers. However, while standards aren't mandatory, legal regulation is, and legal mandates for interoperability are increasingly discussed by policymakers as a remedy for competition issues (see, e.g., ). As such, 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 . That opportunity also presents a risk, however, 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 improved and new capabilities (especially liaison, likely originating in the IAB), and considerable effort. If the Internet community does not make that effort, it is likely that regulators will turn to other sources of interoperability specifications -- most likely, with less transparency, more narrow input, limited experience, and without reference to the Internet’s architectural goals.

Evaluate New Decentralization Techniques The decentralization techniques listed in are not a closed set; wide interest has spurred development of new approaches, both in general and as solutions to specific problems. For example, secure multi-party computation techniques (see, e.g., ) can be composed to allow parties to compute over private inputs without revealing them. Protocols like and use them to limit the information available to participants in protocols to realize privacy goals; as discussed in doing so might also counteract some sources of centralization. However, as with those covered above, these techniques do not automatically preclude all consolidation; such systems often still require trust, even if it is limited, and that might result in other forms of consolidation emerging. Whether use of these techniques (or others) can meaningfully counteract consolidation is still uncertain. Standards bodies (including the IETF) can serve an important function by incubating them, applying (and, where necessary, developing) architectural guidelines for privacy, security, operability, and other goals, and assuring interoperability. When appropriate, publication on the standards track or as experimental can send signals to implementers, users, and regulators about their fitness for particular purposes.

Enable Switching To minimize centralization, standards-defined functions should have an explicit goal enabling users' switching between implementations and deployments of protocols. One necessary condition for this is the availability of alternatives; breadth and diversity of implementation and deployment are required. explores some factors in protocol design that encourage this outcome. Another factor is the cost of substituting an alternative implementation or deployment by users. This implies that the standard needs to be functionally complete and specified precisely enough to allow substitution. These goals of completeness and diversity are sometimes in tension. 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 ). 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 . Well-timed standards efforts leverage these forces to focus proprietary interests on top of open technology, rather than as a replacement for it.

Control Delegation of Power Some functions might see substantial benefits if they are provided by a third party in communication. Adding a new party to communication can improve:

• 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 sizeable efficiencies over pair-wise buyer/seller trading .
• 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 concentrated 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 concentrating their activity to prevent individual behaviors from being discriminated from each other. 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., ) that allow end users to hide their identity from services, while still accessing them.

However, introducing a new party to communication adds concentration and platform centralization to Internet functions, because it brings opportunities for control and observation. While (as discussed above) standards efforts have a very limited capability to prevent or control the resulting consolidation, designing functions with thoughtful constraints on third party functions can prevent at least the most egregious outcomes. Most often, third parties are added to functions as "intermediaries" or in designated "agent" roles. In general, they should only be interposed because of the positive action of at least one of the primary parties, and 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 are only intended to perform basic functions such as caching. Because of the introduction of HTTPS and the CONNECT method (see ), combined with efforts to encourage its adoption, those intermediaries are now required to be explicitly interposed by one endpoint. See 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 Web site intermediates between buyers and sellers is considered an intermediary, even though it is not formally an intermediary in HTTP (see ). Protocol designers can address the centralization associated with this kind of intermediation by standardising the function, rather than restricting the capabilities of the underlying protocols; see .

Consider Extensibility and Modularity 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 a basis for platform centralization if a powerful entity 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 SOAP protocol's extreme flexibility and 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 and discourages consolidation, 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 Internet community instead of remaining in proprietary hands, further enhancing stability and enabling (but not ensuring) decentralization.

Security Considerations This document does not have a direct security impact on Internet protocols. However, failure to consider centralization might cause a myriad of security issues.

Informative References RAND Corporation The Hypertext Transfer Protocol (HTTP) is a stateless application-level protocol for distributed, collaborative, hypertext information systems. This document describes the overall architecture of HTTP, establishes common terminology, and defines aspects of the protocol that are shared by all versions. In this definition are core protocol elements, extensibility mechanisms, and the "http" and "https" Uniform Resource Identifier (URI) schemes. This document updates RFC 3864 and obsoletes RFCs 2818, 7231, 7232, 7233, 7235, 7538, 7615, 7694, and portions of 7230. University of Notre Dame SCIENCE, Vol. 286, No. 15, p. 509 Columbia Law School University of Chicago Law Review, Vol. 82, p. 573 George Washington University Georgetown University International Security, Vol. 44, No. 1, p. 42 Signal Journal of Legal Studies, Vol. 27 Governance: An International Journal of Policy, Administration, and Institutions, Vol. 25, No. 2, p. 237 Yale Law Journal, Vol. 124, No. 3 OECD Communications of the ACM, Vol. 24, No. 2 The Federalist Papers, No. 51 Harvard Business Review, "Breakthrough Ideas for 2004" Northwestern University Law Review, Vol. 104, No. 2 SFCS '82 Apple Google Journal of Cultural Economy, Vol. 12, No. 4 bitcoinera University of Amsterdam Durham University Radboud University Internet Policy Review, Vol. 10, No. 2 The Turn to Infrastructure in Internet Governance Berkeley Journal of Sociology, Vol. 17 Internet Society Internet Society Global Internet Report RTFM, Inc. Fastly Cloudflare Cloudflare This document describes a mechanism in Transport Layer Security (TLS) for encrypting a ClientHello message under a server public key. Discussion Venues This note is to be removed before publishing as an RFC. Source for this draft and an issue tracker can be found at https://github.com/tlswg/draft-ietf-tls-esni (https://github.com/tlswg/draft-ietf-tls-esni). Hacker Noon Chapter 2, Engaging with Carol Bacchi Ethereum This document discusses the Border Gateway Protocol (BGP), which is an inter-Autonomous System routing protocol. The primary function of a BGP speaking system is to exchange network reachability information with other BGP systems. This network reachability information includes information on the list of Autonomous Systems (ASes) that reachability information traverses. This information is sufficient for constructing a graph of AS connectivity for this reachability from which routing loops may be pruned, and, at the AS level, some policy decisions may be enforced. BGP-4 provides a set of mechanisms for supporting Classless Inter-Domain Routing (CIDR). These mechanisms include support for advertising a set of destinations as an IP prefix, and eliminating the concept of network "class" within BGP. BGP-4 also introduces mechanisms that allow aggregation of routes, including aggregation of AS paths. This document obsoletes RFC 1771. [STANDARDS-TRACK] This memo gives a mission statement for the IETF, tries to define the terms used in the statement sufficiently to make the mission statement understandable and useful, argues why the IETF needs a mission statement, and tries to capture some of the debate that led to this point. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Pervasive monitoring is a technical attack that should be mitigated in the design of IETF protocols, where possible. This RFC is the revised specification of the protocol and format used in the implementation of the Domain Name System. It obsoletes RFC-883. This memo documents the details of the domain name client - server communication. This document is a specification of the basic protocol for Internet electronic mail transport. It consolidates, updates, and clarifies several previous documents, making all or parts of most of them obsolete. It covers the SMTP extension mechanisms and best practices for the contemporary Internet, but does not provide details about particular extensions. Although SMTP was designed as a mail transport and delivery protocol, this specification also contains information that is important to its use as a "mail submission" protocol for "split-UA" (User Agent) mail reading systems and mobile environments. [STANDARDS-TRACK] The Extensible Messaging and Presence Protocol (XMPP) is an application profile of the Extensible Markup Language (XML) that enables the near-real-time exchange of structured yet extensible data between any two or more network entities. This document defines XMPP's core protocol methods: setup and teardown of XML streams, channel encryption, authentication, error handling, and communication primitives for messaging, network availability ("presence"), and request-response interactions. This document obsoletes RFC 3920. [STANDARDS-TRACK] This document explains why the IAB believes that, when there is a conflict between the interests of end users of the Internet and other parties, IETF decisions should favor end users. It also explores how the IETF can more effectively achieve this. The Internet community has specified a large number of protocols to date, and these protocols have achieved varying degrees of success. Based on case studies, this document attempts to ascertain factors that contribute to or hinder a protocol's success. It is hoped that these observations can serve as guidance for future protocol work. This memo provides information for the Internet community. This document describes a protocol that allows clients to hide their IP addresses from DNS resolvers via proxying encrypted DNS over HTTPS (DoH) messages. This improves privacy of DNS operations by not allowing any one server entity to be aware of both the client IP address and the content of DNS queries and answers. This experimental protocol has been developed outside the IETF and is published here to guide implementation, ensure interoperability among implementations, and enable wide-scale experimentation. Mozilla This document proposes a set of principles for designing protocols with rules for intermediaries. The goal of these principles is to limit the ways in which intermediaries can produce undesirable effects and to protect the useful functions that intermediaries legitimately provide.

Acknowledgements This document benefits from discussions with Brian Trammell during our shared time on the Internet Architecture Board. Thanks to Jari Arkko, Kristin Berdan, Christian Huitema, Mallory Knodel, Eliot Lear, Tommy Pauly, and Martin Thomson for their comments and suggestions.