The Abstract of the RFC is:

This document specifies a mechanism for protecting hosts connected to
a switched network against rogue DHCPv6 servers.  It is based on
DHCPv6 packet filtering at the layer 2 device at which the packets
are received.  A similar mechanism has been widely deployed in IPv4
networks ('DHCP snooping'); hence, it is desirable that similar
functionality be provided for IPv6 networks.  This document specifies
a Best Current Practice for the implementation of DHCPv6-Shield.