IPv6 equivalent to DHCP Option 82 for geolocating customer MACs to certain ports of Multi-port Layer 2 demarcation devices

[Florian Weimer]

* Ben Jencks:

> If you don't want to use stateful DHCPv6, you don't actually get to
> assign addresses, so you just have to observe what the clients do. You
> can do this with ARP table scraping on the router and MAC table
> scraping on the access switches.

Is there a technology which allows you to run such a configuration in
a secure way without sacrificing at least a /64 per host?