HP 6125XLG - Page 52

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Figure 18 Sub-VLAN-based multicast VLAN
IGMP snooping manages router ports in the multicast VLAN and user ports in each sub-VLAN. Switch A
forwards only one copy of the received multicast data to the multicast VLAN on Switch B. Switch B
replicates the multicast data and sends the copy to each sub-VLAN of the multicast VLAN.
Port-based multicast VLAN
As shown in Figure 19:
• 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 19 Port-based multicast VLAN
IGMP snooping manages the router ports and user ports in the multicast VLAN. When Switch B receives
an IGMP message from a user port, it tags the message with the multicast VLAN ID and sends it to the
IGMP querier. Switch A forwards only one copy of the received multicast data to the multicast VLAN on
Switch B. Switch B replicates the multicast data and sends a separate copy to each user port in the
multicast VLAN.