Receiver-initiated group membership protocol (RGMP): A new group management protocol for IP multicasting

Internet multicast is an important networked service for many existing and emerging applications. The dominant mechanism for group management of IP multicasting is the Internet group management protocol (IGMP). IGMP is based on a query/reply model and refreshes group membership periodically. IGMP has been evolving through three versions. IGMP v1 develops the basis of the query/reply group management model and suppression mechanism, IGMP v2 reduces leave latency that IGMP v1 suffers from, and IGMP v3 adds the capability of source filtering but removes the suppression mechanism of IGMP v1/v2. In this paper, a new group management protocol called receiver-initiated group membership protocol (RGMP) is proposed. Both source filtering and membership report suppression are supported. An RGMP host actively refreshes group membership in the neighboring multicast routers. No querier, and hence no query messages and timers, is required for periodically probing the presence of known groups. An individual host maintains a refresh timer per group. The refresh timer is reset once the suppression rule holds for a received report message, where the report may be a join, leave, state change, or a periodical refresh message. The receiver-initiated, self-synchronized refresh timer makes the RGMP suppression mechanism superior to that of IGMP v1/v2, which applies only for periodical refresh report message. As a result, the protocol overhead compared to IGMP v3 is significantly reduced, over a wide variety of service scenarios. In addition to reduced protocol overhead, RGMP is robust, scalable and adaptive to serve as a group management protocol.