How to choose IPv6 addresses for customer links?

[Martin Horneffer]

Hello,

I'd like to collect opinions from the experienced IPv6 network
engineers that meet here so nicely:

Consider a service provider that provides IPv6 services to leased line
customers.
In almost all cases the customer gets a /48 out of the aggregate of
the service provider.
In many cases and probaly in most future-oriented cases the physical
interface is some kind of ethernet (10/100/100/10000 Mbit/s). Thus the
link to the customer needs its own addresses.
Some customers might want operate their own routers and maintain
several subnets. But some customers might also be happy with having
just one subnet and probably some kind of (layer-2) switches.

My questions is now: How should the addresses for the link network be
chosen?

My understanding would be that it might be best to select one /64 out
of the customer's /48. And to route the complete /48 to one address of
that /64.
Thus the customer can easily put their hosts in the simple /64 if they
only have layer-2 devices.
Or they can set up their own router. It would have to use the address
mentioned above from the link network and can use up to 65535 more /64
subnets. They lose one /64 for the link network, though.

Would that be a sensible addressing scheme? Or would a customer insist
to get a completely independet /64 for the link addresses?


Best regards,  Martin

-- 
Dr. Martin Horneffer
Deutsche Telekom Netzproduktion GmbH
Technical Engineering Center

Deutsche Telekom Netzproduktion GmbH
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