300
MLD configuration (available only on the
A5500 EI)
MLD overview
An IPv6 router uses the Multicast Listener Discovery (MLD) protocol to discover the presence of multicast
listeners on the directly attached subnets. Multicast listeners are nodes that want to receive IPv6 multicast
packets.
Through MLD, the router can determine whether any IPv6 multicast listeners exist on the directly
connected subnets, put corresponding records in the database, and maintain timers related to IPv6
multicast addresses.
Routers that are running MLD use an IPv6 unicast link-local address as the source address to send MLD
messages. MLD messages are Internet Control Message Protocol for IPv6 (ICMPv6) messages. All MLD
messages are confined to the local subnet, with a hop count of 1.
NOTE:
The term
router in this chapter refers to both routers and Layer 3 switches.
The interfaces in this chapter refer to Layer 3 interfaces in generic sense and Ethernet interfaces
operating in route mode. For more information about the operating mode of the Ethernet interface,
see the
Layer 2—LAN Switching Configuration Guide.
MLD versions
The following MLD versions are available:
•
MLDv1—Defined in RFC 2710, which is derived from IGMPv2.
•
MLDv2—Defined in RFC 3810, which is derived from IGMPv3.
All MLD versions support the Any-Source Multicast (ASM) model. In addition, you can directly use
MLDv2 to implement the Source-Specific Multicast (SSM) model, but MLDv1 needs to work with the MLD
SSM mapping function to implement SSM service.
NOTE:
For more information about the ASM and SSM models, see the chapter “Multicast overview.”
How MLDv1 works
MLDv1 implements IPv6 multicast listener management based on the query/response mechanism.
MLD querier election
Of multiple IPv6 multicast routers on the same subnet, all the routers can monitor MLD listener report
messages (often called “reports”) from hosts, but only one router is needed for sending MLD query
Summary of Contents for A5500 EI Switch Series
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