8 T P Timer events 18 27 22 POP3 Timers client 16 14 21 23 29 25 11 13 Triggered events - higher-layer 14 17 13 21 10 10 V 28 10 R 10 7 8 7 9 S Security 27 27 Sequencing rules 17 17 17 18 17 18 17 21 21 21 22 21 Server abstract data model 20 19 21 21 22 21 21 21 22 21 22 21 21 21 22 21 22 21 10 11
8 P 27 POP3 client 14 23 25 13 14 13 10 10 28 R 7 8 7 9 S Security 27 27 Sequencing rules 17 17 17 18 17 18 17 21 21 21 22 21 Server abstract data model 20 19 21 21 22 21 21 21 22 21 22 21 21 21 22 21 22 21 10 11 T Timer events 18 22 Timers 16 21 29 11 Triggered events - higher-layer 17 21 V 10 10