Research On Remote Procedure Call Over Data Distribution Service

Data Distribution Service(DDS)is the distributed real-time communication middleware standard published by Object Management Group(OMG).Its data-centric communication decouples subscribers from publishers,has efficient real-time transmission capabilities,and provides rich QoS policies that is widely used in real-time distributed systems providing publish/subscribe communications.Usually in large distributed systems,more than one type of communications is required.DDS works great for one-to-many dissemination of information.However,other communication styles like request/reply and remote method invocation are cumbersome to express using DDS.Using two or more middleware is not practical due to complexity,cost and maintenance.To solve this problem,this thesis proposes a remote procedure call(RPC)mechanism based on DDS.This mechanism uses the basic components of DDS to provide users with the semantics of request/reply.It describes services provided by the server using interfaces to realize remote procedure call.The main contributions of the thesis are:1.An implementation solution of RPC over DDS and its key mechanisms is proposed,provides services to upper application with semantics of remote procedure calls.DDS and RPC communication characteristics are researched.The system architecture is designed according to the RPC over DDS specification published by OMG organization and key mechanisms are put forward:interface-based service representation,request/response and publish/subscribe semantic mapping mechanisms,communication mechanisms with information filtering and request/reply matching function,and the service binding mechanism based on the SDP protocol which solves the "race-condition"problem.2.An RPC over DDS prototype is designed and implemented based on the aforementioned implementation solution and a DDS middleware named Information Integration Software.The system consists of four modules:the procedure call services are implemented in the client processing model,the request acception and implementation functions are implemented in service processing module,the exception services are handled in the exception processing model,and data serialization and deserialization and information encapsulation services are processed in protocol processing module.3.The function tests and performance tests of the RPC over DDS prototype are accomplished to show that the RPC over DDS mechanism is valid.The results illustrate that the RPC over DDS prototype system can provide remote procedure call development efficiently using DDS.