sverweij/mscgen_js

# SIP protocol with an intermediate proxy (source: wikipedia)
msc {
  Alice, P1, P2, Bob;

  Alice->P1 [label="INVITE"];
  Alice<-P1 [label="100 Trying"];
  P1->P2    [label="INVITE"];
  P1<-P2    [label="100 Trying"];
  P2->Bob   [label="INVITE"];
  P2<-Bob   [label="100 Trying"];
  P2<-Bob   [label="180 Ringing"];
  P1<-P2    [label="180 Ringing"];
  Alice<-P1 [label="180 Ringing"];
  ---       [label="Alice's client plays ringing"];
  ...;
  
  ---       [label="Bob answers"];
  P2<-Bob   [label="200 Ok"];
  P1<-P2    [label="200 Ok"];
  Alice<-P1 [label="200 Ok"];
  Alice->P1 [label="ACK"];
  P1->P2    [label="ACK"];
  P2->Bob   [label="ACK"];
  ---       [label="two way media"];
  ...;
  
  ---       [label="Bob hangs up"];
  P2<-Bob   [label="BYE"];
  P2->Bob   [label="200 Ok"];
  P1<-P2    [label="BYE"];
  P1->P2    [label="200 Ok"];
  Alice<-P1 [label="BYE"];
  Alice->P1 [label="200 Ok"];
}