Back-to-Basics Weekend Reading - U-Net: A User-Level Network Interface
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Many of you know Thorsten von Eicken as the founder of Rightscale, the company that has helped numerous organizations find their way onto AWS. In what seems almost a previous life by now Thorsten was one of the top young professors in Distributed Systems and I had the great pleasure of working with him at Cornell in the early 90’s. What set Thorsten aside from so many other system research academics was his desire to build practical, working systems, a path that I followed as well.
In the back to basics readings this week I am re-reading a paper from 1995 about the work that I did together with Thorsten on solving the problem of end-to-end low-latency communication on high-speed networks. The problem we were facing in those days was than many new high-speed network technologies, such as ATM, became available for standard workstations but that the operating systems were not able to deliver those capabilities to its applications. Throughput was often acceptable but individual message latency was as bad as over regular ethernet, a problem that Chandu Tekkath had described earlier in “Limits to Low-Latency Communication on High-Speed Networks”
The lack of low-latency made that distributed systems (e.g. database replication, fault tolerance protocols) could not benefit from these advances at the network level. The research to unlock these capabilities led to an architecture called U-Net. What set U-Net aside from other research was that it was first and foremost and engineering effort as we set out to build a system that actually had to function in production. Many of those engineering experiences found their way back into the paper. U-Net also heavily influenced what later became the Virtual Network Architecture industry standard.
The work on U-Net was continued by Matt Welsh who built among other things a version that could be used for fast-ethernet on regular PCs and one that could safely integrate into type-safe environments such as the JVM.
U-Net: A User-Level Network Interface for Parallel and Distributed Computing, Anindya Basu, Vineet Buch, Werner Vogels, Thorsten von Eicken. Proceedings of the 15th ACM Symposium on Operating Systems Principles (SOSP), Copper Mountain, Colorado, December 3-6, 1995