Switch Features 79Internet 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).Protocol Independent Multicast—Sparse ModeProtocol Independent Multicast-Sparse Mode (PIM-SM) is used to efficientlyroute multicast traffic to multicast groups that may span wide area networks,and where bandwidth is a constraint. PIM-SM uses shared trees by defaultand implements source-based trees for efficiency. This data threshold rate isused to toggle between trees.Protocol Independent Multicast—Source Specific MulticastProtocol Independent Multicast—Source Specific Multicast (PIM-SSM) is asubset of PIM-SM and is used for one-to-many multicast routingapplications, such as audio or video broadcasts. PIM-SSM does not use sharedtrees.Protocol Independent Multicast IPv6 SupportPIM-DM and PIM-SM support IPv6 routes.
