Multicast Listener Discovery (MLD) is classified as MLDv1 or MLDv2. MLDv1 supports the ASM model, whereas MLDv2 supports ASM and SSM models.
Multicast Listener Discovery (MLD) is a sub-protocol of the Internet Control Message Protocol version 6 (ICMPv6). MLD is used to set up and maintain group memberships between user hosts and their directly connected multicast devices. The functions and principles of MLD are similar to those of IGMP.
MLD has two versions:
MLDv1
MLDv1 is derived from IGMPv2 and supports the ASM model. With the help of SSM mapping, MLDv1 supports the SSM model.
MLDv2
MLDv2 is derived from IGMPv3 and supports ASM and SSM models.