Chapter 3 Multicast Vlan Configuration; Introduction To Multicast Vlan; Configuring Multicast Vlan - H3C S5500-SI Series Manual

Operation Manual – Multicast Protocol
H3C S5500-SI Series Ethernet Switches

Chapter 3 Multicast VLAN Configuration

3.1 Introduction to Multicast VLAN

As shown in Figure 3-1, in the traditional multicast programs-on-demand mode, when
hosts that belong to different VLANs, Host A, Host B and Host C require multicast
programs on demand service, Router A needs to forward a separate copy of the
multicast data in each VLAN. This results in not only waste of network bandwidth but
also extra burden on the Layer 3 device.
Multicast packet transmission
Source
HostA
Receiver
Figure 3-1 Before and after multicast VLAN is enabled on the Layer 2 device
To solve this problem, you can enable the multicast VLAN feature on Switch A, namely
configure the VLANs to which these hosts belong as sub-VLANs of a multicast VLAN
on the Layer 2 device and enable Layer 2 multicast in the multicast VLAN. After this
configuration, Router A replicates the multicast data only within the multicast VLAN
instead of forwarding a separate copy of the multicast data to each VLAN. This saves
the network bandwidth and lessens the burden of the Layer 3 device.

3.2 Configuring Multicast VLAN

Follow these steps to configure a multicast VLAN:
Enter system view
without Multicast VLAN
RouterA
SwitchA
VLAN10 VLAN 30
VLAN 20
HostC
Receiver
HostB
Receiver
Multicast Packets
To do...
system-view
Chapter 3 Multicast VLAN Configuration
Multicast packet
when Multicas
Source
VLAN 111
VLAN10
VLAN 2
HostA
Receiver
Receiver
Use the command...
3-1
transmission
t VLAN runs
RouterA
SwitchA
VLAN 30
0
HostC
Receiver
HostB
Remarks
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