+------------+              +------------+
 | Sensor     |              | Aggregator |
 |            |              |            | 
 +---+--------+              +------+-----+
     |                              |
  Sensors                           |
  trigger                           |
  emergency                         |
  alert                             |
     |    SIP MESSAGE with CAP      |
     |----------------------------->|
     |                              |
     |                           Aggregator
     |                           processes
     |                           emergency
     |                           alert
     |      SIP 200 (OK)            |
     |<-----------------------------|
     |                              |
     |                              |