IPv6 Multicast Destination Addresses
When sending to a multicast destination address, the Microsoft IPv6 protocol normally requires that the application have an outgoing interface specified. This is done with the IPV6_MULTICAST_IF socket option or by binding the socket to a specific source address.
You can also specify a default interface for a specific multicast address, an entire multicast address scope, or all multicast addresses. This is done with a route that places the multicast prefix on-link to the desired outgoing interface. For following examples show how this can be specified:
ipv6 rtu ff02::5/128 3
ipv6 rtu ff0e::/16 3
ipv6 rtu ff00::/8 3