54
Figure 21 Sub-VLAN-based multicast VLAN
IGMP snooping manages router ports in the multicast VLAN and member ports in each sub-VLAN.
When Switch A receives multicast data from the multicast source, it sends only one copy of the
multicast data to the multicast VLAN on Switch B. Then, Switch B sends a separate copy to each
sub-VLAN in the multicast VLAN.
Port-based multicast VLAN
As shown in
•
Host A, Host B, and Host C are in VLAN 2 through VLAN 4, respectively.
•
On Switch B, VLAN 10 is a multicast VLAN. All the user ports are hybrid ports and are assigned
to VLAN 10.
•
IGMP snooping is enabled for the multicast VLAN and VLAN 2 through VLAN 4.
Figure 22 Port-based multicast VLAN
IGMP snooping manages the router ports and member ports in the multicast VLAN. When Switch A
receives multicast data from the multicast source, it sends only one copy of the multicast data to the
multicast VLAN on Switch B. Switch B sends a separate copy to each user port in the multicast
VLAN.
Source
Switch A
IGMP querier
VLAN 2
VLAN 3
VLAN 4
Switch B
Receiver
Host A
Receiver
Host B
Receiver
Host C
Multicast packets
VLAN 2
VLAN 3
VLAN 4
VLAN 10 (Multicast VLAN)
Source
VLAN 2
VLAN 3
VLAN 4
HGE1/0/1
HGE1/0/2
HGE1/0/3
HGE1/0/4
Switch B
Multicast packets
Receiver
Host A
Receiver
Host B
Receiver
Host C
Switch A
IGMP querier
VLAN 10 (Multicast VLAN)