      | State
      |    0         1         2         3         4         5         6         7         8           9
Events| Initial   Starting  Closed    Stopped   Closing   Stopping  Req-Sent  Ack-Rcvd  Ack-Sent    Opened
------+-----------------------------------------------------------------------------------------------------
 Up   |    2     irc,scr/6     -         -         -         -         -         -         -           -
 Down |    -         -         0       tls/1       0         1         1         1         1         tld/1
 Open |  tls/1       1     irc,scr/6     3r        5r        5r        6         7         8           9r
 Close|    0       tlf/0       2         2         4         4     irc,str/4 irc,str/4 irc,str/4 tld,irc,str/4
      |                                                            
  TO+ |    -         -         -         -       str/4     str/5     scr/6     scr/6     scr/8         -
  TO- |    -         -         -         -       tlf/2     tlf/3     tlf/3p    tlf/3p    tlf/3p        -
      |                                                            
 RCR+ |    -         -       sta/2 irc,scr,sca/8   4         5       sca/8   sca,tlu/9   sca/8   tld,scr,sca/8
 RCR- |    -         -       sta/2 irc,scr,scn/6   4         5       scn/6     scn/7     scn/6   tld,scr,scn/6
 RCA  |    -         -       sta/2     sta/3       4         5       irc/7     scr/6x  irc,tlu/9   tld,scr/6x
 RCN  |    -         -       sta/2     sta/3       4         5     irc,scr/6   scr/6x  irc,scr/8   tld,scr/6x
      |                                                            
 RTR  |    -         -       sta/2     sta/3     sta/4     sta/5     sta/6     sta/6     sta/6   tld,zrc,sta/5
 RTA  |    -         -         2         3       tlf/2     tlf/3       6         6         8       tld,scr/6
      |                                                            
 RUC  |    -         -       scj/2     scj/3     scj/4     scj/5     scj/6     scj/7     scj/8       scj/9
 RXJ+ |    -         -         2         3         4         5         6         6         8           9
 RXJ- |    -         -       tlf/2     tlf/3     tlf/2     tlf/3     tlf/3     tlf/3     tlf/3   tld,irc,str/5
      |                                                            
 RXR  |    -         -         2         3         4         5         6         7         8         ser/9


   Events                                   Actions

   Up   = lower layer is Up                 tlu = This-Layer-Up
   Down = lower layer is Down               tld = This-Layer-Down
   Open = administrative Open               tls = This-Layer-Started
   Close= administrative Close              tlf = This-Layer-Finished

   TO+  = Timeout with counter > 0          irc = Initialize-Restart-Count
   TO-  = Timeout with counter expired      zrc = Zero-Restart-Count

   RCR+ = Receive-Configure-Request (Good)  scr = Send-Configure-Request
   RCR- = Receive-Configure-Request (Bad)
   RCA  = Receive-Configure-Ack             sca = Send-Configure-Ack
   RCN  = Receive-Configure-Nak/Rej         scn = Send-Configure-Nak/Rej

   RTR  = Receive-Terminate-Request         str = Send-Terminate-Request
   RTA  = Receive-Terminate-Ack             sta = Send-Terminate-Ack

   RUC  = Receive-Unknown-Code              scj = Send-Code-Reject
   RXJ+ = Receive-Code-Reject (permitted)
       or Receive-Protocol-Reject
   RXJ- = Receive-Code-Reject (catastrophic)
       or Receive-Protocol-Reject
   RXR  = Receive-Echo-Request              ser = Send-Echo-Reply
       or Receive-Echo-Reply
       or Receive-Discard-Request
