Re: [v6ops] Discussion focus: draft-ietf-v6ops-ipv6rtr-reqs

[Lorenzo Colitti <[e-mail]>]

On Fri, Jan 5, 2018 at 11:01 AM, Brian E Carpenter <
[e-mail]> wrote:

> > Help me understand. Are you saying that mobile hotspots should implement
> > DHCPv6 because this draft says so, but then never turn it on because it's
> > bad for their users?
>
> Lorenzo, are you saying that the requirements in this draft need to be
> scoped? That doesn't sound unreasonable, but if so, what would the
> scoping text look like?
>

Yes, I think that's the problem. The document takes a bit of a
one-size-fits all approach. You also don't need netconf/yang/syslog on a
mobile hotspot. Nor does it make sense to say "the I2RS interface to the
RIB be supported" on a home router that has one default route and two
directly-connected subnets. You probably also don't need DHCPv6 or RAs on a
backbone router that's primarily intended as an LSR or segment router.

IETF standards are about interoperability, they are not shopping lists.
(For an example of a document that suffered from this problem to a much
greater degree, see RFC 7849, which was taken out of the WG and published
as individual submission.)

Not sure how best to address this. A couple of options that come to mind
are:

   1. Removing the parts of the draft that are essentially a device profile
   ("routers must support X, Y and Z").
   2. Changing the aforementioned parts of the draft so that instead of
   saying "routers must support X" they say "if routers support X, they must
   support RFCs A, B, and C". An example is section 3.1. Instead of saying
   "routers must support DHCPv6, SLAAC, first-hop router selection, etc." it
   could say "if routers are intended to act as first-hop routers for hosts,
   they must support...", and "if routers are intended to be
   operator-configurable, then they must allow disabling SLAAC and enabling
   DHCPv6". This is what RFC 7084 does - it defines a basic profile that
   everything must support, and then consists of a large number of statements
   along the lines of "if the CE router supports X, then it must do A, B, and
   C".
   3. Defining a number of device profiles that have mandatory
   requirements. This risks turning the document into a number of shopping
   lists, but perhaps those will be easier to get consensus on.

Cheers,
Lorenzo