Netgear XCM8810 - 8800 SERIES 10-SLOT CHASSIS SWITCH ユーザーズマニュアル

In the topology above, the MSP multicast VLAN is carried on two switches that also carry the 
customer multicast VLAN. When multiple switches carry both multicast VLANs, it is 
imperative that MVR is configured on only one switch. Only that switch should be used as the 
transit point for multicast streams from one multicast ring into another. Otherwise, duplicate 
packets are forwarded. Also on the non-MVR switches, the ring ports should be configured as 
static router ports, so that ring ports are excluded from forwarding packets onto the customer 
ring. There is no mechanism to elect a designated MVR forwarder, so it must be configured 
correctly. 

MVR Configurations

MVR enables Layer 2 network installations to deliver bandwidth intensive multicast streams. 
It is primarily aimed at delivering IPTV over Layer 2 networks, but it is valuable in many 
existing STP installations. This section explores a few possible deployment scenarios and 
configuration details. Of course, real world networks can be lot different from these examples. 
This section is meant to present some ideas on how to deploy MVR over existing networks, 
as well as to design new networks that support MVR.

In a Layer 2 ring topology, MVR works with STP. However, in other Layer 2 topologies, 
additional configuration steps may be needed to make sure that multicast feeds reach all 
network segments. Extra configuration is required because all ports in the VLAN are part of 
an STP domain, so that solely by examining the configuration it is not clear whether a port is 
part of bigger ring or is just serving a few hosts. Consider a simplified Layer 2 STP network 
as shown in 

.