+---------+ ---------\      active OPEN  
                               |  CLOSED |            \    -----------  
                               +---------+<---------\   \   create TCB  
                                 |     ^              \   \  snd SYN    
                    passive OPEN |     |   CLOSE        \   \           
                    ------------ |     | ----------       \   \         
                     create TCB  |     | delete TCB         \   \       
                                 V     |                      \   \     
                 rcv RST       +---------+            CLOSE    |    \   
          -------------------->|  LISTEN |          ---------- |     |  
        /                      +---------+          delete TCB |     |  
       |            rcv SYN      |     |     SEND              |     |  
       |           -----------   |     |    -------            |     V  
  +---------+      snd SYN,ACK  /       \   snd SYN          +---------+
  |         |<-----------------           ------------------>|         |
  |   SYN   |                    rcv SYN                     |   SYN   |
  |   RCVD  |<-----------------------------------------------|   SENT  |
  |         |                  snd SYN,ACK                   |         |
  |         |------------------           -------------------|         |
  +---------+   rcv ACK of SYN  \       /  rcv SYN,ACK       +---------+
    |           --------------   |     |   -----------                  
    |                  x         |     |     snd ACK                    
    |                            V     V                                
    |  CLOSE                   +---------+                              
    | -------                  |  ESTAB  |                              
    | snd FIN                  +---------+                              
    |                   CLOSE    |     |    rcv FIN                     
    V                  -------   |     |    -------                     
  +---------+          snd FIN  /       \   snd ACK          +---------+
 -|  FIN    |<-----------------           ------------------>|  CLOSE  |
/ | WAIT-1  |------------------                              |   WAIT  |
| +---------+          rcv FIN  \                            +---------+
|   | rcv ACK of FIN   -------   |                            CLOSE  |  
|   | --------------   snd ACK   |                           ------- |  
|   V        x                   V                           snd FIN V  
| +---------+                  +---------+                   +---------+
| |FINWAIT-2|                  | CLOSING |                   | LAST-ACK|
| +---------+                  +---------+                   +---------+
|   |                rcv ACK of FIN |                 rcv ACK of FIN |  
|   |  rcv FIN       -------------- |    Timeout=2MSL -------------- |  
|   |  -------              x       V    ------------        x       V  
|    \ snd ACK                 +---------+delete TCB         +---------+
|     ------------------------>|TIME WAIT|------------------>| CLOSED  |
 \                             +---------+                   +---------+
  \                                 ^
   \     rcv FIN,ACK                /
     ------------------------------/
           snd ACK
  
	                               TCP Connection State Diagram