Netgear M5300-28G-POE+ (GSM7228PSv1h2) - 12-Port Managed Gigabit Switch Ratgeber Für Administratoren

The IGMP Layer 3 protocol is widely used for IPv4 network multicasting. In Layer 2 networks, 
the IGMP protocol uses resources inefficiently. For example, a Layer 2 switch multicast traffic 
to all ports even if there are receivers connected to only a few ports.

To fix this problem, the IGMP snooping protocol was developed. But the problem reappears 
when receivers are in different VLANs. Multicast VLAN registration (MVR) is intended to 
solve the problem of receivers in different VLANs. It uses a dedicated manually configured 
VLAN, called the multicast VLAN, to forward multicast traffic over Layer 2 network in 
conjunction with IGMP snooping.

MVR, like the IGMP Snooping protocol, allows a Layer 2 switch to snoop on the IGMP control 
protocol. Both protocols operate independently of each other. Both protocols can be enabled 
on the switch interfaces at the same time. In such a case, MVR listens to the join and report 
messages only for groups configured statically. All other groups are managed by IGMP 
snooping.

There are two types of MVR ports: source and receiver.

The source port is the port to which the multicast traffic flows using the multicast VLAN.

The receiver port is the port where a listening host is connected to the switch. It can 
utilize any (or no) VLAN, except the multicast VLAN. This implies that the MVR switch 
performs VLAN tag substitution from the multicast VLAN source port to the VLAN tag 
used by the receiver port.

The multicast VLAN is the VLAN that you configure in the specific network for MVR 
purposes. The multicast VLAN is used to transfer multicast traffic over the network to avoid 
duplication of multicast streams for clients in different VLANs. The operator must configure 
the multicast VLAN manually for all source ports in the network. A diagram of a network 
configured for MVR is shown in the following illustration. SP is the source port and RP is the 
receiver port.