On Fri, Jul 8, 2022, 09:22 Andrei Borzenkov <arvidjaar@xxxxxxxxx> wrote:
On 07.07.2022 18:25, Bent Bagger wrote:
>
> The prefix delegation problem starts with the interactions between net0
> and net2. Net0 is delegated a /56 prefix from the main router (which
> runs radvd and dhcpd6, not networkd, for historical reasons). I want
> net2 to delegate a /60 subnet to net3, but it doesn't happen.
networkd does not support prefix subdelegation. It supports querying
upstream for delegated prefixes and allocating one /64 received prefix
to downstream interface announcing it via RA. The same functionality as
NetworkManager. Nor does networkd support DHCPv6 server functionality.
For all practical purposes IPv6 on-link prefix can only be /64. So
"delegated a /56 prefix" is misleading. You get delegated block of
prefixes that are aggregated into /56 mask.
IME, "prefix" is a *very* common term for routed prefixes, not only on-link ones – probably much more common than "/56 mask" (given that nothing uses actual mask notation in IPv6). The upstream router doesn't care about whether you're going to use it as on-link prefixes or not, anyway.
