Just finished watching the IPv6 videos from Keith's CCNA course, and I feel like I have a decent handle on NDP but this seems odd to me:
After a host recieves a router advertisement which is sourced by the downstream router with its link local address for that segment, why doesn't the host just use the router's link local address in the neighbor solicitation that follows? It's more specific, and to do otherwise the host has to break the router's link local down and convert it to create the selected node multicast address.
I'm sure there's a good reason, but it seems like an unnecessary additional step. Why would we prefer multicast in this scenario over unicast?