734
18.4 MLD Snooping
18.4.1 MLD Snooping Introduction
MLD
, the Multicast Listener Discovery Protocol, is used to realize multicasting in the
IPv6. MLD is used by the network equipments such as routers which supports multicast
for multicast listener discovery, also used by listeners looking forward to join certain
multicast group informing the router to receive data packets from certain multicast
address, all of which are done through MLD message exchange. First the router send an
MLD Multicast listener Query message through a multicast address which can address
all the listeners (namely ff02::1). Once there is a listener who wishes to join the multicast
address, it will send a MLD Multicast listener Report back through the multicast address.
MLD Snooping is namely the MLD listening. The switch restricts the multicast traffic
from flooding through MLD Snooping, and forward the multicast traffic to ports associated
to multicast devices only. The switch listens to the MLD messages between multicast
routers and listeners, and maintains the multicast group forwarding list based on the
listening result. The switches forwards multicast packets according to the multicast
forwarding list
The switch realizes the MLD Snooping function while supporting MLD v2. This way,
the user can acquire IPv6 multicast with the switch.
18.4.2 MLD Snooping Configuration Task
1. Enable the MLD Snooping function
2. Configure the MLD Snooping
1.
Enable the
MLD Snooping
function
Command
Explanation
Global Mode
ipv6 mld snooping
no ipv6 mld snooping
Enable global MLD Snooping, the “
no ipv6 mld
snooping
” command disables the global MLD
snooping
2.
Configure MLD Snooping
Command
Explanation
Global Mode