The majority of FCR‘s will agree to an identical result in the presents of an arbitrary fault in a FCR


  • Indenticaly results in the majority of FCR‘s can only be obtained, if the input data are identical (input congruency requirement)
  • The FCR‘s must be connected by cross-strapped point to point data path (connectivity requirement)
  • The FCR‘s must be synchronised by a known skew (synchronisation requirement)
  • The Byzantine law with f = number of arbitrary faults to be tolerated:

Redundance (FCR‘s):

R = 3 f + 1

Connectivity (Links per FCR):

N = 2 f + 1

Distribution rounds:

K = f + 1


Fault tolerant clock