1998 - 1999 CS Annual Report                                                                  Faculty
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Kenneth P. Birman


PhD UC Berkeley, 1981

My research is concerned with reliability and security in modern networked environments. This work has three broad themes. 

Our main focus is on a new system called "Spinglass". The idea is to explore a class of reliable multicast protocols that are extremely scalable, and provide unusually stable
throughput under stress. We believe that stable throughput is a common requirement in demanding critical settings, but few reliable protocols have this property. The Bimodal

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Multicast protocol underlying Spinglass appears to be a real step forward, because it not only provides this guarantee, but also has a unique form of reliability a bimodal probabilistic delivery distribution, which can be formally derived and has been confirmed in practice. We see a tremendous number of fascinating challenges as we extend this into a full-scale system and develop tools to program with bimodal reliability. The work involves our whole group. Graduate students looking at Bimodal Multicast and the Spinglass per-se system
include Oznur Ozkasap, Indranil Gupta and Zhen Xiao. Ken Hopkinson is looking at some issues raised when one tries to "reason" about applications designed to use Bimodal Multicast. 

A second focus involves developing formal methods to prove properties of reliable communication protocols, such as those used in Isis, Horus and Ensemble. These employ a reliability model called virtual synchrony, which provides a mixture of guarantees involving the membership of groups of processes in a dynamic distributed setting, handling of failures and recoveries, multicast to group members, and tools for initializing a joining process. Our work is joint with R. Constable's Nuprl project and N. Lynch's group at MIT, and uses Lynch's I/O Automata to formalize the behavior of Ensemble, after which Nuprl can be exploited to reason about and manipulate complex protocol stacks. Robbert van Renesse and graduate student Xioaming Liu are leading this activity. 

Our third focus is on ways of embedding reliability tools into widely used software settings. Werner Vogels is pursuing this in a component-based system he calls Quintet. The emphasis of Quintet is on developing very scalable cluster solutions for scalable, high performance, fault-tolerant servers. R. van Renesse is doing something similar, but his focus is on system management issues, using a system he called the RMIB. Bela Ban is developing a Java embedding of Ensemble, and graduate student Ben Atkin is embedding Spinglass into CMU's RVM, a transactional distributed shared memory system. As for me, I'm looking at the restructured electric power system as a
potential source of challenging applications needing large-scale secure and reliable communication tools. Our hope through these efforts is to understand the needs better, looking at real and important technology areas, to show how such problems can be solved, and to demonstrate the solutions in settings of commercial importance. 

Finally, Tibor Janosi, Rimon Barr and Adrian Bozdog are developing a reliable and scalable architecture for electronic brokerage systems. Newspapers have reported many scalability problems with the existing systems of this sort. Our effort will explore architecture and systems challenges in making such systems scale to support really large numbers of clients. Not only is
the problem itself interesting, we hope to gain insight into how our new tools can be exploited in leading-edge application settings. 

Our project is funded primarily by DARPA, with some additional funding from the Electric Power Research Institute and DDR&E. The project is directed by myself, R. van Renesse, and W. Vogels. B. Ban is visiting as a post-doc during 1998-2000, and Raoul Bhoedjang will be joining us in the fall. T. Clark manages our software distribution effort and generally keeps things running. 

University Activities 

  • Director: Graduate Studies, Computer Science 
  • University Conflicts of Interest Committee 
  • Presidential Search, Cornell Research Foundation 
  • Engineering College Policy Committee 
  • Academic Leadership Series 
  • The Next Generation Internet: Unsafe at Any Speed? Univ. of Virginia, Apr. 1998. 
  • . CERN, Geneva, Switzerland, July 1998. 
  • . Lucent Laboratories, NJ, Oct 1998. 
  • . Computer Science Department, Univ. of Madrid, March 1999. 
  • . 17th Brazilian Symposium on Computer Networks,  Bimodal Multicast. Carnegie Mellon Univ., Dec. 1999. 
  • . Computer Science Department, Univ. of Madrid, March 1999. 
  • . 17th Brazilian Symposium on Computer Networks, Salvador di Bahia, June 1999. 
  • Bimodal multicast. ACM Transactions on Computer Systems 17 (May 1999) (with M. Hayden, O. Ozkasap, Z. Xiao, M. Budiu and Y. Minsky). 
  • The Isis Toolkit (used in the New York Stock and Swiss Stock Exchanges, next-generation French Air Traffic Control System, other projects) 
  • Horus system  Ensemble System and the Maestro Toolkit 
  • Spinglass System