--- Paxos Proposer ---

 1  proposer(v):
 2    while not decided:
 3      choose n, unique and higher than any n seen so far
 4      send prepare(n) to all servers including self
 5      if prepare_ok(n, na, va) from majority:
 6        v' = va with highest na; choose own v otherwise   
 7        send accept(n, v') to all
 8        if accept_ok(n) from majority:
 9          send decided(v') to all
    
    
    --- Paxos Acceptor ---

10  acceptor state on each node (persistent):
11   np     --- highest prepare seen
12   na, va --- highest accept seen
    
13  acceptor's prepare(n) handler:
14   if n > np
15     np = n
16     reply prepare_ok(n, na, va)
17   else
18     reply prepare_reject
    
    
19  acceptor's accept(n, v) handler:
20   if n >= np
21     na = n
22     va = v
23     reply accept_ok(n)
24   else
25     reply accept_reject