Protocol Independence Using the Sockets API

The BSD sockets API provides abstractions and other features that help applications be protocol-independent. Unfortunately, not all of the API is abstract and generic, and many programs do not use the APIs in a protocol- independent way. This means that most network programs, in practice, only work with one layered set of communications protocols - usually TCP over IP. This hinders compatibility with older protocols and deployment of new ones, and is making IP a victim of its own success.

During the course of next-generation IP development, implementors worked to convert protocol-dependent applications into protocol-independent applications. Along the way, they defined new interfaces to fix some problems and they found a number of usage problems that lead to protocol dependencies.

This paper explains many of the problems encountered, using examples from freely available software, and how to solve them. It also explains many of the new protocol-independent interfaces.