Re: [v6ops] draft-templin-v6ops-pdhost a working group draft?

[Brian E Carpenter <[e-mail]>]

On 16/11/2017 18:35, Templin, Fred L wrote:
> Hi Gunter,
> 
>> -----Original Message-----
>> From: v6ops [mailto:[e-mail]] On Behalf Of Van De Velde, Gunter (Nokia - BE/Antwerp)
>> Sent: Wednesday, November 15, 2017 6:31 PM
>> To: Fred Baker <[e-mail]>; [e-mail]
>> Subject: Re: [v6ops] draft-templin-v6ops-pdhost a working group draft?
>>
>> Does this mean that the document desires to include all the dynamics of address assignment subscriber management when PD is
>> used? (i.e. subscriber vs address correlation state, identification of the subscriber/host, etc...)?
> 
> This draft is about what a host can do internally when it gets a prefix delegation

What is a bit confusing is whether, having acquired a prefix, it's going
to turn itself into a forwarding device. If so, surely there is nothing
to say except that IPv6 router requirements apply. (Which does not
mean it's going to run a routing protocol, since it can default route
everything to its upstream. But things like redirects are covered by
6434(bis), which also mandates that routers must send RAs etc.)

So I guess my point is: what is specific to a host about the discussion
in this document? Just to take an example, in section 4:

   When the node receives the prefix, it can distribute the prefix to
   downstream networks and configure one or more addresses for itself on
   downstream interfaces.  The node then acts as a router on behalf of
   its downstream networks and configures a default route via a neighbor
   on an upstream interface.

So that is describing what a *router* does, not what a host does.

If it's *not* going to be a forwarding device, I wonder what it's
going to use the prefix for? Also in section 4:

   The node could instead (or in addition) use portions of the delegated
   prefix for its own multi-addressing purposes.  In a first
   alternative, the node can assign as many addresses as it wants from
   the prefix to virtual interfaces.  In that case, applications running
   on the node can use the addresses according to the weak end system
   model.

Fair enough. But it's very confusing to mix the end host behaviours
in with the router behaviours. And since a lot of the document is
about router behaviours, the document title itself is confusing.
(I don't agree with Lorenzo that the host/router distinction is
confusing in itself.)

I suggest
(a) changing the title. Something like "IPv6 Prefix Delegation Models".
(b) refactoring the contents to clearly separate the router-like
    and host-like behaviours.

Also, perhaps, identify any points that would be better moved
into 6434bis (or 6434ter).

With those changes I'd be happy to see this as a WG draft.

   Brian