Why used DHCPv6 when RA has RDNSS and DNSSL?

[otroan at employees.org]

> DHCPv6-PD works, and AFAIK it is implemented by every vendor wanting to
> be taken seriously.
> 
> HNCP probably works too.  Time will tell, if/when it is actually
> implemented at a scale making it possible to test it outside the lab.
> 
> HNCP is currently irrelevant wrt end host addressing.  It depends on
> either DHCPv6 or SLAAC there.

As one of the authors of DHCPv6 PD, I might be biased.
But PD was analysed in detail for the homenet use case and was found wanting.

It does not support multiple sources of information (think multihoming).
Hierarchical PD does not deal with arbitrary topologies. Think having to implement a spanning tree with PD.
HNCP is the IETF's answer to this.

Considering how poorly hosts deal with multiple addresses, I'm not sure we have operational experience justifying pushing even more addresses to hosts (ref /64).

If we want to discuss how to deal with multiple links, I always thought the idea of multilink subnet routing, with the same /64 crossing multiple links showed promise. Regardless I think experience has shown that the "anarchy" that SLAAC brings with it has operational issues. Forcing the use of DHCP for address assignment. Or requiring modifications to SLAAC, e.g. introduction of something like the ARO option.

Cheers,
Ole