ZyXEL Communications IES-708-22A - Manual (Page 159)

IES-708-22A User’s Guide
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H A P T E R
20
Multicast VLAN
This feature is available in STU-C mode only.
This chapter describes the Multicast VLAN screens.
20.1 Multicast VLAN Overview
Multicast VLAN allows one single multicast VLAN to be shared among different subscriber
VLANs on the network. This improves bandwidth utilization by reducing multicast traffic in
the subscriber VLANs and simplifies multicast group management.
When the IES-708-22A forwards traffic to a subscriber port, it tries to forward traffic to a
normal PVC with the same VLAN ID. If this PVC does not exist, the IES-708-22A uses the
super channel instead. This applies to all downstream traffic, not just multicast traffic.
It is suggested to use a super channel for multicast VLAN. If a normal PVC is used and the
multicast VLAN ID is not the same as the PVC’s VID, the IES-708-22A does not forward
traffic to this PVC even if the subscriber’s port has joined the multicast VLAN.
Since the IES-708-22A might change the subscriber’s VLAN ID to the multicast VLAN ID,
both the subscriber’s port and the Ethernet port should join the multicast VLAN.
20.2 MVLAN Status Screen
Use this screen to look at a summary of all multicast VLAN on the IES-708-22A. To open this
screen, click Advanced Application > Multicast VLAN.
Figure 75 Advanced Application > Multicast VLAN