ZyXEL Communications ZyXEL Dimension ES-3124 - Manual (Page 172)

Dimension ES-3124 Ethernet Switch
22-6 Multicast
22.5 MVR Overview
Multicast VLAN Registration (MVR) is designed for applications (such as Media-on-Demand (MoD)) that use
multicast traffic across an Ethernet ring-based service provider network.
MVR allows one single multicast VLAN to be shared among different subscriber VLANs on the network. While
isolated in different subscriber VLANs, connected devices can subscriber to and unsubscribe from the multicast
stream in the multicast VLAN. This improves bandwidth utilization with reduced multicast traffic in the subscriber
VLANs and simplifies multicast group management.
You must enable IGMP snooping to use MVR. However, MVR only responds to IGMP join and leave control
messages from multicast groups that are configured under MVR. Join and leave reports from other multicast groups
are managed by IGMP snooping.
The following figure shows a network example. The subscriber VLAN (1, 2 and 3) information is hidden from the
streaming media server, S. In addition, the multicast VLAN information is only visible to the switch and S.
Figure 22-4 MVR Network Example
22.5.1 Types of MVR Ports
In MVR, a source port is a port on the switch that can send and receive multicast traffic in a multicast VLAN while
a receiver port can only receive multicast data. Once configured, the switch maintains a forwarding table that
matches the multicast stream to the associated multicast group.
22.5.2 MVR Modes
You can set your switch to operate in either dynamic or compatible mode.
In dynamic mode, the switch sends IGMP leave and join reports to the other multicast devices (such as multicast
routers or servers) in the multicast VLAN. This allows the multicast devices to update the multicast forwarding
table to forward or not forward multicast traffic to the receiver ports.
In compatible mode, the switch does not send any IGMP reports. In this case, you must manually configure the
forwarding settings on the multicast devices in the multicast VLAN.