Deno: DEcentralized Network Objects

 Goal
The goal is to investigate decentralized, "homeless" approaches to consistency maintenance in shared object databases. To this end, we are building Deno, a new shared-object infrastructure specifically designed to support replicated data in mobile and unreliable, wide-area environments.

The following are key attributes of our approach:

  • Decentralized consistency maintainence - Deno objects have no "home", and no dedicated owner. Instead, objects "flow" to where they are accessed. Responsibility is handed off in pairwise fashion. Objects are located using hints. Advantages of this approach are:
    1. No single point of failure.
    2. Disconnection of no one node can prevent updates from being made to any event.
    3. No serialization hot spots.
  • Reliability - Replication is used to adjust object reliability to application constraints.
  • Mobile and disconnected operation - Deno transparently supports mobile environments by avoiding global consistency guarantees.

 Papers
  • U. «etintemel, P. J. Keleher, B. Bhattacharjee, and M. J. Franklin. Deno: A Decentralized, Peer-to-Peer Object-Replication System for Weakly-Connected Environments. IEEE Transactions on Computers (TOCS), 52(7), July 2003. [pdf]
  • U. «etintemel and P. J. Keleher. Light-Weight Currency Management Mechanisms in Mobile and Weakly-Connected Environments. Journal of Distributed and Parallel Databases, 11(1), pages 53-71, January 2002. [pdf]
  • U. «etintemel, P. J. Keleher, and M. J. Franklin. Support for Speculative Update Propagation and Mobility in Deno. In proceedings of the 21th IEEE International Conference on Distributed Computing Systems (ICDCSí01), Phoenix, Arizona, April 2001. [pdf]
  • U. «etintemel and P. J. Keleher. Performance of Mobile, Single-Object Replication Protocols. In proceedings of the 19th IEEE Symposium on Reliable Distributed Systems (SRDSí00), Nurnberg, Germany, October 2000. [pdf]
  • U. «etintemel and P. J. Keleher. Light-Weight Currency Management Mechanisms in Deno. In proceedings of the 10th IEEE Workshop on Research Issues in Data Engineering (RIDE 2000) on "Middleware for Mobile Business Applications and E-Commerce", San Diego, CA, March 2000 (best paper award). [pdf]
  • P. J. Keleher and U. «etintemel. Consistency Management in Deno. In ACM-Baltzer Journal on Special Topics in Mobile Networking and Applications (MONET), 5(4), pages 299-309, 2000. [pdf]
 People
Software
  • The Linux and Win32 implementation of Deno can be found here.
  • The WinCE version will soon be available.