Notes: This article is absurdly long, and I don’t expect you to read every part of it closely (or necessarily at all). Instead, the article is interesting because it is an attempt to make a technical principle normative. Solum and Chung argue that the architecture of the Internet as it currently exists (as of 2004, when they were writing, that is) is layered. They then claim that laws should respect that architecture: lawmakers should not write laws that cross between layers, or that undermine the layering itself. This is an interesting kind of argument! Remember that Lessig said law can change architecture–Solum and Chung are saying that architecture should drive law.
Questions:
What is “layering”? Is it something that we only see on the Internet, or can other systems also be layered?
Was the Internet actually layered in 2004 when they wrote? Is it layered now in 2023?
Just because the Internet is layered now, does it follow that it it should be layered? (What do Solum and Chung say? Are there counterarguments? Better arguments that they fail to make?)
What makes a law “layer-crossing”? Is this a coherent category, or a catch-all term for bad Internet laws?
Does the layers principle imply network neutrality?
Have you seen this type of attempt to make technical principles normative anywhere else? Are those other attempts persuasive?
Additional Resources:
The Cursed Computer Iceberg Meme. Computers are deeply weird. We talk about them using logical and well-structured abstractions, but sometimes—often—those abstractions break down. This is a compilation of incredible, and frequently hilarious, stories about times when those abstractions broke down.
Eric Wustrow, Scott Wolchok, Ian Goldberg, and J. Alex Halderman, Telex: Anticensorship in the Network Infrastructure, Proceedings of the 20th USENIX Security Symposium (USENIX Security ‘11) (2011). An interesting technical proposal to help users circumvent governmental censorship, which depends in a fundamental way on violating the layers principle. See also the authors’ companion sites for Telex and its descendant Refraction Networking and my blog post about Telex, Planet Telex.
Larry Patterson and Bruce Davie Computer Networks: A Systems Approach (Morgan Kaufmann 6th ed. 2021). This is my personal favorite networking textbook; it presents the standard model of the Internet. It is useful to read while pondering the question of where the layers principle comes from.
Pamela Zave and Jennifer Rexford, The Real Internet Architecture (Princeton University Press 2024). This book gives a more modern model of Internet architecture, including developments like VPNs, firewalls, and CDNs. It is useful to read while pondering whether the Internet today obeys the layers principle.
Barbara van Schewick, Internet Architecture and Innovation (MIT Press 2010). A thorough and detailed analysis of the role that the layers principle and the related end-to-end principle play in Internet policy. The literature review is exceptional; if you are going to do serious research on Internet architecture and law, this is an essential reference.
J[erome] H. Saltzer, D[avid] P. Reed, and D[avid] D. Clark, End-to-End Arguments in System Design, 2 ACM Transactions on Computer Systems 277 (1984). This is the paper that introduced the end-to-end principle; it remains highly readable and a canonical reference.
Jerome H. Saltzer and M. Frans Kaashoek, Principles of Computer System Design: An Introduction (Morgan-Kaufmann 2009). This is a full-on computer-science textbook about system design. Part I is only legally available in print, but Part II is free online and includes a chapter about layers and modularity in networks. A good place to look to understand how system designers think about abstractions.