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Multicast Forwarding
Configuring MLD Snooping
Configuring MLD Snooping
STEP 1
STEP 2
Cisco 220 Series Smart Plus Switches Administration Guide Release 1.0.0.x
To support selective Multicast forwarding (IPv6), MLD Snooping must be enabled
globally and for each relevant VLAN. The switch supports MLD Snooping only on
static VLANs. It does not support MLD Snooping on dynamic VLANs.
Hosts use the MLD protocol to report their participation in Multicast sessions, and
the switch uses MLD Snooping to build Multicast membership lists. It uses these
lists to forward Multicast packets only to switch ports where there are host nodes
that are members of the Multicast groups. The switch does not support MLD
Querier.
The switch supports two versions of MLD Snooping:
•
MLDv1 Snooping detects MLDv1 control packets, and sets up traffic
bridging, based on IPv6 destination Multicast addresses.
•
MLDv2 Snooping uses MLDv2 control packets to forward traffic based on
the source IPv6 address, and the destination IPv6 Multicast address.
The actual MLD version is selected by the Multicast router in the network.
In an approach similar to IGMP Snooping, MLD frames are snooped as they are
forwarded by the switch from stations to an upstream Multicast router and vice
versa. This facility enables a switch to conclude the following:
•
On which ports stations interested in joining a specific Multicast group are
located
•
On which ports Multicast routers sending Multicast frames are located
This knowledge is used to exclude irrelevant ports (ports on which no stations
have registered to receive a specific Multicast group) from the forwarding set of an
incoming Multicast frame.
If you enable MLD Snooping in addition to the manually-configured Multicast
groups, the result is a union of the Multicast groups and port memberships derived
from the manual setup and the dynamic discovery by MLD Snooping. However,
only the static definitions are preserved when the switch is rebooted.
To enable MLD Snooping:
Click Multicast > MLD Snooping.
Enter the following IGMP Snooping general paramters:
•
MLD Snooping Version—Select either MLDv1 or MLDv2.
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