In IPv4, Layer 2 switches can use 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 address. 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 configured to receive IPv6 multicast packets) on its directly attached links 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 IGMPv3. MLD is a subprotocol of Internet Control Message Protocol version 6 (ICMPv6), and MLD messages are a subset of ICMPv6 messages, identified in IPv6 packets by a preceding Next Header value of 58.
The switch can snoop on both MLDv1 and MLDv2 protocol packets and bridge IPv6 multicast data based on destination IPv6 multicast MAC addresses. The switch can be configured to perform MLD snooping and IGMP snooping simultaneously.
For more information, see the following support articles:
- What is Multicast Listener Discovery (MLD) and how does it work with my managed switch?
- How do I configure Multicast Listener Discovery (MLD) snooping using the web interface on my managed switch?
This article applies to the following managed switches and their respective firmware:
- M5300 - firmware version 10.0.0.x
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- M5300-28G (GSM7228S)
- M5300-5G (GSM7252S)
- M5300-28G3 (GSM7328Sv2h2)
- M5300-52G3 (GSM7352Sv2h2)
- M5300-28G_POE+ (GSM7228PSv1h2)
- M5300-52G-POE+ (GSM7252PSv1h2)
- M5300-28GF3 (GSM7328FSv2)
- XSM7224S - firmware version 9.0.1.x (license required to support the feature described in this article)