H3C Technologies H3C S3100 Series Switches - Manual (Page 309)

3-2
Figure 3-1 Before and after MLD snooping is enabled on the Layer 2 device
IPv6 multicast packet transmission
without MLD Snooping
Source
Multicast router
Host A
Receiver
Host B
Host C
Receiver
IPv6 multicast packets
Layer 2 switch
IPv6 multicast packet transmission
when MLD Snooping runs
Source
Multicast router
Host A
Receiver
Host B
Host C
Receiver
Layer 2 switch
MLD snooping forwards multicast data to only the receivers requiring it at Layer 2. It brings the following
advantages:
z Reducing Layer 2 broadcast packets, thus saving network bandwidth.
z Enhancing the security of multicast traffic.
z Facilitating the implementation of per-host accounting.
Basic Concepts in MLD Snooping
MLD Snooping related ports
As shown in Figure 3-2 , Router A connects to the multicast source, MLD snooping runs on Switch A and
Switch B, Host A and Host C are receiver hosts (namely, IPv6 multicast group members).
Figure 3-2 MLD snooping related ports
Router A Switch A
Switch B
Eth1/0/1 Eth1/0/2
Eth1/0/3
Eth1/0/1
Eth1/0/2
Receiver
Receiver
Host A
Host B
Host C
Host D
IPv6 multicast packets
Router port
Member port