| dc.description.abstract | Data Distribution Service (DDS) is becoming the most recent trends in net centric system and able to do mission critical information management. DDS is an application which acts as the middleware between applications and use publish-subscribe communication model. In DDS, Data Reliability and Throughput are two important performances quality that can be measured. In many cases, during the communication in DDS there will be some problem occurred, such as packet loss rate and outdated packets which lead to data reliability and throughput problem respectively. In order to deal with those issues, OMG as the standard of DDS, provide rich set of adjustable QoS policy which enable the system to optimize the communication in DDS including the data reliability and throughput. However, the same QoS policy settings cannot be used to solve all the problem due to the resource constraint. The DDS might run under enough resource or limited resource condition. In order to deal with the data reliability and throughput issue over specified resource condition, different QoS policies settings are required.
Several experiment scenarios are conducted in order to solve the data reliability and throughput problem. In scenario 1, the experiment will be conducted in order to find the resource state of the system (whether the system is running under enough resource or limited resource). In scenario 2, the QoS policy will be adjusted to optimize the data reliability for all topics by keeping all the packets into cache history, and resend the missing packets. In scenario 3, the QoS policy will be adjusted to optimize the data reliability for several topics only. In Scenario 4, the QoS policy will be adjusted to optimize the data reliability for all topics by keeping all the packets into cache history and limit the sending rate. In scenario 5, the QoS policy will be adjusted to minimize the period of the packets transmission and optimize the throughput by increasing the number of max samples.
Based on the conducted experiments, the proposed QoS policies settings can solve data reliability and throughput problem when the system is running under enough resource or limited resource condition. | en_US |