Switch Features 83Layer 3 Multicast FeaturesFor information about configuring L3 multicast features, see "Managing IPv4and IPv6 Multicast" on page 1153.Distance Vector Multicast Routing ProtocolDistance Vector Multicast Routing Protocol (DVMRP) exchanges probepackets with all DVMRP-enabled routers, establishing two way neighboringrelationships and building a neighbor table. It exchanges report packets andcreates a unicast topology table, which is used to build the multicast routingtable. This multicast route table is then used to route the multicast packets.Internet Group Management ProtocolThe Internet Group Management Protocol (IGMP) is used by IPv4 systems(hosts and routers) to report their IP multicast group memberships to anyneighboring multicast routers. PowerConnect 7000 Series switches performthe “multicast router part” of the IGMP protocol, which means it collects themembership information needed by the active multicast router.IGMP ProxyThe IGMP Proxy feature allows the switch to act as a proxy for hosts bysending IGMP host messages on behalf of the hosts that the switchdiscovered through standard IGMP router interfaces.Protocol Independent Multicast—Dense ModeProtocol Independent Multicast (PIM) is a standard multicast routingprotocol that provides scalable inter-domain multicast routing across theInternet, independent of the mechanisms provided by any particular unicastrouting protocol. The Protocol Independent Multicast-Dense Mode (PIM-DM) protocol uses an existing Unicast routing table and a Join/Prune/Graftmechanism to build a tree. PIM-DM creates source-based shortest-pathdistribution trees, making use of reverse path forwarding (RPF).
