A posteriori Agreement for Fault-tolerant Clock Synchronization on Broadcast Networks.

L. Rodrigues and P. Veríssimo

A shorter version of this report was published in the Digest of Papers, The 22th International Symposium on Fault-Tolerant Computing, July, 1992, Boston - USA.


We present a clock synchronization algorithm, dubbed a posteriori agreement, based on a new variant of the well-known convergence non-averaging technique. By exploiting an obvious characteristic of broadcast networks, the effect of message delivery delay variance is largely reduced. In consequence, the precision achieved by the algorithm is drastically improved. Accuracy preservation is near to optimal. Our solution, however, does not require the use of dedicated hardware.

Also available extended report (gzip postscript), (pdf) .

Luís Rodrigues