708 Configuring L2 Multicast Featurespermanently assigned (well-known) multicast address FF0x::/12 to all ports inthe VLAN, except for MLD packets, which are handled according the MLDsnooping rules.What Is Multicast VLAN Registration?IGMP snooping helps limit multicast traffic when member ports are in thesame VLAN; however, when ports belong to different VLANs, a copy of themulticast stream is sent to each VLAN that has member ports in themulticast group. MVR eliminates the need to duplicate the multicast trafficwhen multicast group member ports belong to different VLANs.MVR uses a dedicated multicast VLAN to forward multicast traffic over theL2 network. Only one MVLAN can be configured per switch, and it is usedonly for certain multicast traffic, such as traffic from an IPTV application, toavoid duplication of multicast streams for clients in different VLANs. Clientscan dynamically join or leave the mutlicast VLAN without interfering withtheir membership in other VLANs.MVR, like IGMP snooping, allows a layer 2 switch to listen to IGMP messagesto learn about multicast group membership.There are two types of MVR ports: source and receiver.• Source port is the port where multicast traffic is flowing to. It has to be themember of so called multicast VLAN.• Receiver port is the port where listening host is connected to the switch. Itcan be the member of any VLAN, except multicast VLAN.NOTE: It is strongly recommended that users enable IGMP snooping if MLDsnooping is enabled and vice-versa. This is because both IGMP snooping andMLD snooping utilize the same forwarding table, and not enabling both maycause unwanted pruning of protocol packets utilized by other protocols, e.g.OSPFv2.
