Almost Peer-to-Peer Clock Synchronization

In this paper, an almost peer-to-peer (AP2P) clock synchronization protocol is proposed. AP2P is almost peer-to-peer in the sense that it provides the desirable features of a purely hierarchical (client/server) clock synchronization protocol while avoiding the undesirable consequences of a purely peer-to-peer one. In AP2P, a unique node is elected as a leader in a distributed manner. Each non-leader node adjusts its clock rate based on message exchanges with its neighbors, taking into consideration that neighbors that are closer to the leader have more effect on the adjustment than the neighbors that are further away from the leader. We compare the performance of AP2P with that of the server time protocol (STP), which is a purely hierarchical clock synchronization protocol. Simulation results, which have been conducted on several network topologies, have shown that AP2P can provide a clock synchronization accuracy that is indistinguishable from that of STP. Furthermore, AP2P is more fault-tolerant because it can recover from certain types of failures that STP cannot recover from.

[1]  Bill Ogden,et al.  Ibm system z9 109 technical introduction , 2005 .

[2]  Deborah Estrin,et al.  Directed diffusion for wireless sensor networking , 2003, TNET.

[3]  Jennifer L. Welch,et al.  Self-Stabilizing Clock Synchronization in the Presence of ByzantineFaults ( Preliminary Version ) Shlomi Dolevy , 1995 .

[4]  Hagit Attiya,et al.  Optimal clock synchronization under different delay assumptions , 1993, PODC '93.

[5]  Flaviu Cristian,et al.  Probabilistic clock synchronization , 1989, Distributed Computing.

[6]  P. M. Melliar-Smith,et al.  Synchronizing clocks in the presence of faults , 1985, JACM.

[7]  Ellen W. Zegura,et al.  How to model an internetwork , 1996, Proceedings of IEEE INFOCOM '96. Conference on Computer Communications.

[8]  Danny Dolev,et al.  Dynamic fault-tolerant clock synchronization , 1995, JACM.

[9]  Scott D. Stoller.  Leader Election in Asynchronous Distributed Systems , 2000, IEEE Trans. Computers.

[10]  David L. Mills,et al.  Network Time Protocol (Version 3) Specification, Implementation and Analysis , 1992, RFC.

[11]  Cathy H. Xia,et al.  Clock synchronization algorithms for network measurements , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[12]  Dahlia Malkhi,et al.  Omega Meets Paxos: Leader Election and Stability Without Eventual Timely Links , 2005, DISC.

[13]  Kang G. Shin,et al.  Probabilistic clock synchronization in large distributed systems , 1991, [1991] Proceedings. 11th International Conference on Distributed Computing Systems.

[14]  Hector Garcia-Molina,et al.  Elections in a Distributed Computing System , 1982, IEEE Transactions on Computers.

[15]  J.E. Abate,et al.  AT&T's new approach to the synchronization of telecommunication networks , 1989, IEEE Communications Magazine.

[16]  Boaz Patt-Shamir,et al.  Optimal and efficient clock synchronization under drifting clocks , 1999, PODC '99.

[17]  I. Cidon,et al.  Network time synchronization using clock offset optimization , 2003, 11th IEEE International Conference on Network Protocols, 2003. Proceedings..

[18]  Scott D. Stoller.  Leader Election in Distributed Systems with Crash Failures , 1999 .