Dell N3200-ON EMC Networking N-Series Switches CLI Reference Guide version 6.7 - Page 1488

IGMPv3 is a major revision of the protocol and provides improved group membership latency. When a host joins a new multicast group on an interface, it immediately sends an unsolicited IGMP Report message for that group. IGMPv2 introduced a Leave Group message, which is sent by a host when it leaves a multicast group for which it was the last host to send an IGMP Report message. Receipt of this message causes the Querier possibly to reduce the remaining lifetime of its state for the group, and to send a groupspecific IGMP Query message to the multicast group.The Leave Group message is not used with IGMPv3, since the source address filtering mechanism provides the same functionality. IGMPv3 also allows hosts to specify the list of hosts from which they want to receive traffic. Traffic from other hosts is blocked inside the network. It also allows hosts to block packets for all sources sending unwanted traffic. IGMPv3 adds the capability for a multicast router to learn which sources are of interest to neighboring systems for packets sent to any particular multicast address. This information gathered by IGMP is provided to the multicast routing protocol (that is, DVMRP, PIM-DM, and PIM-SM) that is currently active on the router in order to ensure multicast packets are delivered to all networks where there are interested receivers. IGMP mode is automatically enabled when PIM, DVMRP, or IGMP Proxy is enabled. ip igmp last-member-query-count Use the ip igmp last-member-query-count command in Interface Configuration mode to set the number of Group-Specific Queries sent before the router assumes that there are no local members on the interface. Syntax ip igmp last-member-query-count Imqc no ip igmp last-member-query-count • Imqc - Query count. (Range: 1-20) Default Configuration The default last member query count is 2. Layer 3 Routing Commands 1488