C H A P T E R
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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
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Configuring IPv6 MLD Snooping
You can use Multicast Listener Discovery (MLD) snooping to enable efficient distribution of IP
Version 6 (IPv6) multicast data to clients and routers in a switched network on the switch. Unless
otherwise noted, the term
switch
refers to a standalone switch and to a switch stack.
Note
To use IPv6, you must configure the dual IPv4 and IPv6 Switch Database Management (SDM) template
on the switch. You select the template by entering the
sdm prefer
dual-ipv4-and-ipv6
{
default
|
routing
|
vlan
} global configuration command.
For related information, see these chapters:
•
For more information about SDM templates, see
Chapter 8, “Configuring SDM Templates.”
•
For information about IPv6 on the switch, see
Chapter 39, “Configuring IPv6 Unicast Routing.”
Note
For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release or the Cisco IOS documentation referenced in the procedures.
This chapter includes these sections:
•
“Understanding MLD Snooping” section on page 25-1
•
“Configuring IPv6 MLD Snooping” section on page 25-5
•
“Displaying MLD Snooping Information” section on page 25-11
Understanding MLD Snooping
In IP Version 4 (IPv4), Layer 2 switches can use Internet Group Management Protocol (IGMP) snooping
to limit the flooding of multicast traffic by dynamically configuring Layer 2 interfaces so that multicast
traffic is forwarded to only those interfaces associated with IP multicast devices. In IPv6, MLD snooping
performs a similar function. With MLD snooping, IPv6 multicast data is selectively forwarded to a list
of ports that want to receive the data, instead of being flooded to all ports in a VLAN. This list is
constructed by snooping IPv6 multicast control packets.
MLD is a protocol used by IPv6 multicast routers to discover the presence of multicast listeners (nodes
wishing to receive IPv6 multicast packets) on the links that are directly attached to the routers and to
discover which multicast packets are of interest to neighboring nodes. MLD is derived from IGMP;
MLD Version 1 (MLDv1) is equivalent to IGMPv2, and MLD Version 2 (MLDv2) is equivalent to