"Flour Power: From PAST to present, or Pastry: Scalable, distributed object location and routing for large-scale peer-to-peer systems"

Ant Rowstron

Peer-to-peer (p2p), initially conceived for the purpose of sharing music in the Internet, promises to be a more general paradigm for organizing large-scale distributed applications. We define p2p systems broadly as self-organizing, decentralized, and distributed systems where most or all communication is symmetric. The self-organization, decentralization, diversity and redundancy of resources inherent in the approach lend themselves to a large domain of applications beyond file sharing, anonymity and anti-censorship. At the same time, the decentralization and diversity also pose difficult problems, particularly in resource management and security. Recent work on p2p overlay networks like CAN, Chord, Pastry and Tapestry has made significant strides towards providing a general substrate that simplifies the construction of a wide range of p2p applications. These overlay networks effectively shield applications from the complexities of organizing and maintaining a secure overlay network, tolerating node failure, and from distributing and locating resources. In this talk, I'll present an overview of Pastry, a p2p overlay network that provides self-organization, fault-tolerance, efficient resource location and distribution, and incorporates interesting heuristics that exploit proximity in the underlying Internet. I will also sketch two applications built upon Pastry to date: PAST, an archival, cooperative file storage and distribution facility, and SCRIBE, a highly scalable event notification system. Pastry Project: http://www.research.microsoft.com/~antr/Pastry

Jon Crowcroft

Paraphrasing W. Churchill, one might say "The Internet - the worst network architecture, except for all the rest".

In this talk, I will look at some of the design mistakes (assuming that the Internet was actually designed, rather than discovered, like Tigger and Piglet finding the North Pole), that were made in the selection of algorithms and techniques in the lower levels of the Internet.

The talk will be structured around 20 key problems (well 23, in fact, for readers of the Illuminati trilogy), and will take in alternative solutions, and their relative merits and tradeoffs.

Specific areas of concern are pretty much everything, including naming, addressing, routing, reliability and security, as well as manageability and scaling.

At the end of the talk there will be time for questions, but probably not for answers.