Disclosed are a computing apparatus for providing an entity search means so as to perform data communication between different entities of a Data Distribution Service (DDS) in a multi-network domain environment, and a method of operating the same. A method of operating a computing system for a Data Distribution Service (DDS) service in a DDS system including a first network domain and a second network domain includes: searching for search information of DDS entities included in the first network domain; determining at least a DDS entity among the DDS entities as a representative entity of the first network domain; and providing the search information of the DDS entities to a representative entity of the second network domain through the representative entity of the first network domain.