+----------+         +----------+                  +-----------+
   |Sensor or |         |  ESRP    |                  |   PSAP    |
   |Aggregator|         |          |                  |           |
   +----+-----+         +---+------+                  +----+------+
        |                   |                              |
     Sensors                |                              |
     trigger                |                              |
     emergency              |                              |
     alert                  |                              |
        |                   |                              |
        |                   |                              |
        | SIP MESSAGE w/CAP |                              |
        | (including service URN,                          |
        | such as urn:service:sos)                         |
        |------------------>|                              |
        |                   |                              |
        |              ESRP performs                       |
        |              emergency alert                     |
        |              routing                             |
        |                   |  MESSAGE with CAP            |
        |                   |  (including identity info)   | 
        |                   |----------------------------->|
        |                   |                              |
        |                   |                           PSAP
        |                   |                           processes
        |                   |                           emergency
        |                   |                           alert
        |                   |      SIP 200 (OK)            |
        |                   |<-----------------------------|
        |                   |                              |
        |  SIP 200 (OK)     |                              |
        |<------------------|                              |
        |                   |                              |
        |                   |                              |