Discovery is one of the most important activities in ubiquitous and distributed computing, with a plethora of available protocols. Most of these protocols are designed for one concrete purpose: network nodes discovery, service discovery, search of specific information stored through the network, and so forth. Designing a single discovery system able to deal with the particularities of many different information structures and purposes seems not feasible. Moreover, these data structures possess some underlaying meanings and relationships that are usually hidden from traditional discovery protocols that use simple text-based matchmaking. A semantic discovery protocol could solve this problem by taking advantage of semantically annotated data and performing reasoning over the information to obtain additional knowledge that can be crucial in processing the queries. In this paper, we describe the basics of a novel semantic discovery mechanism called mRDP (Multicast Resource Discovery Protocol) built upon HTTP and Semantic Web technology to provide more powerful discovery capabilities.