Re: [Last-Call] [Anima] Opsdir last call review of draft-ietf-anima-constrained-join-proxy-09

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

Hi Jürgen,
On 05-Apr-22 20:36, Jürgen Schönwälder wrote:
...

>> Pvds==>
>>
>> Now I am confused. I expected you to require more text here.
>>
>> Something seems to be missing in the description of the base line scenario,
>> and I need more info to understand what the missing pieces are.
> 
> I think it is rather obvious for people familiar with IPv6 that (i) if
> you don't have the Registrar's address you can't talk to it and (ii)
> if the Registrar is multiple hops away, you can't talk to it. Things
> that are less obvious are the assumptions made about how devices are
> connected. Apparently (if I understand your response) we are not
> talking about devices joining a regular wireless LAN, i.e., a shared
> link. This is where I got lost, i.e., in which scenario such a Join
> Proxy is applicable. It is not about more or less text, but text that
> helps me to figure out whether this is applicable to my networks or
> not.

This may or may not help, but our general assumption in Anima is that
when bootstrapping a network there is *nothing* in place except
IPv6 link-local addressing, i.e. there is no layer 3 forwarding
anywhere. It's only after the secure joining has happened that the
layer 3 forwarding can be put in place for traffic to and from
the newly joined node. In the general case the layer 2 topology
could be anything, so the mechanisms have to avoid any assumptions
about topology.

The join proxy itself was a pledge when first switched on, until
it discovered it had other links so it needed to behave as a join
proxy too.

(I can see some issues with that as applied in a pure mesh
network, where we'd need a mechanism to prevent every pledge
also becoming a join proxy.)

Regards
    Brian