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An Engineering Perspective on Protocol Layering

Guest Scholar:
Christopher Yoo
Professor of Law
University of Pennsylvania Law School

The layered architecture of the Internet is often lauded as an important source of innovation.  A review of both the engineering and management literature reveals that the relationship between protocol layering and innovation is more complex than this simple perspective suggests.  As an initial matter, the existing architecture is only one of many possible protocol stacks.  Indeed, many thought it would simply be a transitional step toward a different stack with different and greater functionality.  Moreover, layering channels technology in a particular direction, facilitating innovations that are consistent with the existing design hierarchy while impeding innovations that require a different architecture.  Indeed, the engineering literature is replete with articles recognizing that the Internet is not well designed to support many features that end users now demand, such as security, mobility, multicasting, and multihoming.  As a result, the National Science Foundation and the European Commission are sponsoring “clean slate” research designed to help the network overcome the obstacles that are locking it into place.  Interestingly, the fact that network providers and content/application providers offer complementary services necessarily means that the relationship between them possesses both cooperative and noncooperative elements.  On the one hand, they have the incentive to cooperate to jointly maximize surplus.  On the other hand, they simultaneously have the noncooperative incentive to claim the largest proportion of that surplus possible.  The literature on New Institutional Economics suggest that parties in such an industry will attempt to manage this process by entering into strategic partnerships that can be quite complex.  In addition, they may compete by trying to invade each other’s territory, as exemplified by the growing rivalry between Apple and Google.  Rather than use regulation to lock the current layered stack into place, the engineering literature instead suggests that policymakers should “design for tussle” in ways that allows the network architecture to continue to develop and evolve.

Barton Beebe
Professor of Law
New York University School of Law

Steve Bellovin
Professor of Computer Science
Columbia University

Dan Cohen
Dean’s Fellow
Fordham Law School

Jamela Debelak
Executive Director, CLIP
Fordham Law School

Thomas Nachbar
Professor of Law
University of Virginia School of Law

Joel R. Reidenberg
Stanley D. & Nikki Waxberg Professor of Law
Academic Director, CLIP
Fordham Law School

Ira Rubenstein
Research Fellow
New York University School of Law

Adina Schwartz
John Jay College of Criminal Justice

Lawrence Solum
John E. Cribbet Professor of Law
University of Illinois College of Law

Olivier Sylvain
Associate Professor of Law
Fordham Law School

Felix Wu
Assistant Professor of Law
Cardozo School of Law