ZyXEL Communications GS2200-24P Series, Руководство пользователя, Страница: 193 / 360

Chapter 23 Multicast
GS2200-24/24P User’s Guide
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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 98 MVR Network Example
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 traffic.
Once configured, the Switch maintains a forwarding table that matches the
multicast stream to the associated multicast group.
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.
How MVR Works
The following figure shows a multicast television example where a subscriber
device (such as a computer) in VLAN 1 receives multicast traffic from the
streaming media server, S, via the Switch. Multiple subscriber devices can connect
through a port configured as the receiver on the Switch.
When the subscriber selects a television channel, computer A sends an IGMP
report to the Switch to join the appropriate multicast group. If the IGMP report