NetworkManager doesn't use the interface id in IPv6CP as address suffix when doing PPPoE over Vlan
I do PPPoE over a Vlan interface with 802.1Q tagged. I get both IPv4 and IPv6 address. However, because NetworkManager doesn't use the interface-ID in IPv6CP packet as the IPv6 address's suffix and the ISP assigned /128 IPv6 address to me, the IPv6 doesn't work well. There is an error in NetworkManager's logs:"no interface identifier; IPv6 address creation may fail".
As I use my switch to add 802.1Q tag and do PPPoE directly on ethernet Interface, everything works well.