Once a session has been established, the Responder may wish to send a request asynchronously such as a
KEY_UPDATE request but cannot due to the limitations of the physical bus or transport protocol. In such a scenario,
the transport and/or physical layer is responsible for defining an alerting mechanism for the Requester. Upon
receiving the alert, the Requester shall issue a GET_ENCAPSULATED_REQUEST to the Responder.
Once a session has been established, the Responder may wish to send a request asynchronously such as a KEY_UPDATE request but cannot due to the limitations of the physical bus or transport protocol. In such a scenario, the transport and/or physical layer is responsible for defining an alerting mechanism for the Requester. Upon receiving the alert, the Requester shall issue a GET_ENCAPSULATED_REQUEST to the Responder.