Causal Consistency

updating (events):

n1: ------------------------<n1_u1>--------

n2: ------------------------<n2_u1>--------

n3: ---<n3_u1>-----------------------------


ordering:

n1:
       (n3_u1)              (n1_u1) (n2_u1)

n2:
       (n3_u1)              (n2_u1) (n1_u1) 

n3:
       (n3_u1)              (n1_u1) (n2_u1)
  or:
       (n3_u1)              (n2_u1) (n1_u1)