3com 8807 Guia Do Utilizador

Based on the current multicast on demand, when users in different VLANs request 
the service, multicast flow is duplicated in each VLAN and thus a great deal of 
bandwidth is wasted. To solve this problem, we provide the multicast VLAN 
feature. With this feature, you can add switch ports to a multicast VLAN and 
enable IGMP Snooping to allow users in different VLANs to share the same 
multicast VLAN. In this way, multicast flow is transmitted in one multicast VLAN 
instead of multiple user VLANs and bandwidth is greatly saved.

As multicast VLAN is isolated from user VLANs, this guarantees both security and 
enough bandwidth. After you configure the multicast VLAN, multicast information 
flow can be transmitted to users continuously.

Multicast VLAN is based on layer 2 multicast. The following table describes the 
multicast VLAN configuration tasks:

n 

■

A port can only belong to one multicast VLAN.

■

The type of the ports connected to user terminals must be hybrid untagged.

■

The current system supports up to three multicast VLANS.

Table 421   Configure multicast VLAN

Enter system view 

system-view 

- 

Enable IGMP Snooping in 
system view 

igmp-snooping enable 

Required 

Enter VLAN view 

vlan vlan-id 

- 

IGMP Snooping is enabled on 
the VLAN

Enable IGMP Snooping in 
VLAN view 

igmp-snooping enable 

Required 

Enable multicast VLAN 

service-type multicast 

Required 

Quit VLAN view 

quit 

Enter the view of the Ethernet 
port connected to the user 

interface interface-type 
interface-number 

 - 

Define the port type to hybrid  port link-type hybrid 

Required 

Add ports to corresponding 
VLANs 

port hybrid vlan vlan-id-list 
untagged 

Required