Re: [6lo] Draft applicability for 6775bis

[Christian Huitema <[e-mail]>]

On 4/20/2017 9:15 AM, Pascal Thubert (pthubert) wrote:
>
> What about :
>
>  
>
> « 
>
>     This implies that a 6LR or 6LBR which is intended to support N
> hosts MUST have space to register at least on the order of 10N IPv6
> addresses.
>
> « 
>
> ->
>
> « 
>
>     This implies that the capabilities of 6LR and 6LBRs in terms of
> number of registrations must be clearly announced in the router
> documentation, and that a network administrator should deploy adapted
> 6LR/6LBRs to support the number and type of devices in his network,
> based on the number of IPv6 addresses that those devices require.
>
> « 
>
>  
>
> Works ?
>

I don't have a strong opinion on this wording, but I have a
recommendation for the authors of the draft. This discussion outlined a
couple of concerns about potential abuses. For example, I noted the
following:

1) Registration procedure could be used to deny access, by abusing the
administrative rejection option.

2) Nodes registering a large number of IID could overwhelm the
registration system.

I would also add a generic concern about unique identifiers and privacy.
This is an obvious concern in mobility scenarios, but even for static
networks it also is a concern if the option can be observed outside the
network. I understand that the encrypted link provides some mitigation,
but having provisions to vary the IID over time would be even better.

It might be a good idea to document these issues in the security
considerations.

-- Christian Huitema