Channeled Multicast for Group Communications

Multi-agent systems can benefit from the possibility of broadcasting messages to a wide audience. The audience may include overhearing agents which, unknown to senders, observe conversations and, among other things, pro-actively send suggestions. Current mainstream agent communication languages however lack adequate support for broadcasting. This paper defines the requirements for a form of broadcast that we call channeled multicast, whose distinguishing features include the ability to distinguish streams of messages by their theme, and to address agents by their characteristics. We present an implementation based on multicast IP, called LoudVoice. We show how channeled multicast could be used in alternative to matchmaking, and present in some detail a broadcast-based version of the English Auction Interaction Protocol. Finally, we discuss how we use the ability to overhear conversations in order to build innovative applications and we present a case study which is a testbed for various types of agents and multi-agent systems