Tussle in Cyberspace: Defining Tomorrow’s InternetDavid D. ClarkMIT Lab for Computer [email protected] WroclawskiMIT Lab for Computer [email protected] R. SollinsMIT Lab for Computer [email protected] BradenUSC Information Sciences [email protected] architecture of the Internet is based on a number ofprinciples, including the self-describing datagram packet,the end to end arguments, diversity in technology and globaladdressing. As the Internet has moved from a research cu-riosity to a recognized component of mainstream society,new requirements have emerged that suggest new designprinciples, and perhaps suggest that we revisit some oldones. This paper explores one important reality that sur-rounds the Internet today: different stakeholders that arepart of the Internet milieu have interests that may be ad-verse to each other, and these parties each vie to favor theirparticular interests. We call this process “the tussle”. Ourposition is that accommodating this tussle is crucial to theevolution of the network’s technical architecture. We dis-cuss some examples of tussle, and offer some technical designprinciples that take it into account.Categories and Subject DescriptorsC.2.1 [Computer Systems Organization]: ComputerCommunications Networks—Network Architecture and De-sign;H.1[Information Systems]: Models and Principles;K.4.1 [Computing Milieux]: Computers and Society—Public Policy IssuesGeneral TermsDesign, Economics, Legal Aspects, Security, Standardiza-tionKeywordsTussle, Network Architecture, Trust, Economics, DesignPrinciples, CompetitionWork sponsoredin part bythe DefenseAdvancedResearchProjects Agency(DARPA) and Air Force Research Laboratory, Air Force Materiel Com-mand, USAF, under agreement number F30602-00-2-0553 at MIT, andagreement number F30602-00-1-0540 at ISI. The U.S. Government is au-thorized to reproduce and distribute reprints for Governmental purposesnotwithstanding any copyright annotationthereon.Permission to make digital or hard copies of all or part of this work forpersonal or classroom use is granted without fee provided that copies arenot made or distributed for profit or commercial advantage and that copiesbear this notice and the full citation on the first page. To copy otherwise, torepublish, to post on serversor to redistribute to lists, requires prior specificpermission and/or a fee.SIGCOMM’02, August 19-23, 2002, Pittsburgh, Pennsylvania, USA.Copyright 2002 ACM 1-58113-570-X/02/0008...$5.00.1. INTRODUCTIONThe Internet was created in simpler times. Its creatorsand early users shared a common goal—they wanted to builda network infrastructure to hook all the computers in theworld together so that as yet unknown applications couldbe invented to run there. All the players, whether designers,users or operators, shared a consistent vision and a commonsense of purpose.Perhaps the most important consequence of the Internet’ssuccess is that the common purpose that launched and nur-tured it no longer prevails. There are, and have been forsome time, important and powerful players that make upthe Internet milieu with interests directly at odds with eachother.Some examples are very current. Music lovers of a cer-tain bent want to exchange recordings with each other, butthe rights holders want to stop them. People want to talkin private, and the government wants to tap their conversa-tions. Some examples are so obvious that they are almostoverlooked. For the Internet to provide universal intercon-nection, ISPs must interconnect, but ISPs are sometimesfierce competitors. It is not at all clear what interests arebeing served, to whose advantage, to what degree, whenISPs negotiate terms of connection. It is not a single happyfamily of people dedicated to universal packet carriage.We suggest that this development imposes new require-ments on the Internet’s technical architecture. These newrequirements, in turn, motivate new design strategies to ac-commodate the growing tussle among and between differentInternet players. The purpose of this paper is to explorewhat these requirements and strategies might be.We begin by briefly discussing the Internet landscape -some fundamental differences between the mechanisms ofengineering and society, and the players that populate ourfield. We then outline some proposed design principles in-tended to accommodate within the Internet mechanisms ofsociety as well as those of engineering. We believe this ac-commodation is central to designing an Internet that is re-silient to the challenges of society as well as those of tech-nology. We conclude by discussing some tussle spaces, waysin which our principles might guide the technical responseto these spaces, and specific technical research that may beof value in accommodating these tussles.1.1 The natures of engineering and societyEngineers attempt to solve problems by designing mech-347anisms with predictable consequences. Successful engineer-ing yields bridges that predictably don’t fall down, planesthat predictably don’t fall out of the sky, and calculatorsthat give the “right” answer. The essence of engineering isthe development and codification of models, techniques andtools that deliver predictable, desirable behavior.The technical development of the Internet has followedthis path. As a community, we focus on design princi-ples that deliver such virtues as robustness, scalability andmanageability in the face of complexity, component failures,growth, and other challenges. However, as the Internet be-comes mainstream it inevitably moves from being an engi-neering curiosity to being a mirror of the societies in whichit operates. The Internet may have been designed by engi-neers, but its behavior (and its evolution) is by no meanspredictable today.The operation of societies follows a different model. His-torically, the essence of successful societies is the dynamicmanagement of evolving and conflicting interests. Such so-cieties are structured around ‘controlled tussle’ – regulatedby mechanisms such as laws, judges, societal opinion, sharedvalues, and the like. Today, this is the way the Internet isdefined—by a series of ongoing tussles. Different partiesadapt its mix of mechanisms to try to achieve their conflict-ing goals, and others respond by adapting the mechanismsto push back. Thus, conservative governments and corpo-rations put their users behind firewalls, and the users routeand