Design and Implementation of Emergency QoS of Publish-Subscribe Middleware Based on DDS

In the scene of publish / subscribe applications, users usually have QoS (Quality of Service) requirements. In some scenarios, the urgent data need to be delivered preferentially. However, relevant QoS which meets such requirements doesn't exist in DDS specification and commercial publish/subscribe middleware currently. To sovle this problen, the paper put forward an Emergency QoS measure, to modify the scheduler in publish/subscribe, which scheduling data publishing subscription depends on Emergency QoS value, so as to achieve immediate dispose to emergency tasks. Test results reveal that the introduction of Emergency QoS achieves the desired goals.