Re: [v6ops] WGLC: draft-ietf-v6ops-unique-ipv6-prefix-per-host-02 - multiple prefixes per device

[Ross Chandler <[e-mail]>]

> On 20 Mar 2017, at 09:28, Lorenzo Colitti <[e-mail]> wrote:
> 
> Given that this is an operational draft, then I would suggest an applicability statement: state that DHCPv6 PD is better, but also state that best *current* practice is to provide a /64 via RA, because currently very few hosts have DHCPv6 PD clients and providing PD on the network side is not going to help the vast majority of clients.
> 
> Using shared links on public deployments with untrusted hosts has all sorts of security and scalability issues (ND spoofing, DAD spoofing, ND cache exhaustion attacks, etc.) /64 to the host is just a much better solution.



It might also be worth noting in the draft how 3GPP TS.23401 5.3.1.2.6  says prefix shorter than /64 assignment to UEs should work. 

"Optionally a single network prefix shorter than the default /64 prefix may be assigned to a PDN connection. In this case, the /64 default prefix used for IPv6 stateless autoconfiguration will be allocated from this network prefix; the remaining address space from the network prefix can be delegated to the PDN connection using prefix delegation after the default bearer establishment and IPv6 prefix allocation via IPv6 stateless address autoconfiguration as defined in clause 5.3.1.2.2.”

“The UE uses DHCPv6 to request additional IPv6 prefixes (i.e. prefixes in addition to the default prefix) from the PDN GW after completing stateless IPv6 address autoconfiguration procedures.”


Having a single contiguous prefix is allowed for by specifying the minor extra detail of prefix length in CDRs.

Ross