Re: [v6ops] draft-ietf-v6ops-slaac-renum and draft-ietf-v6ops-cpe-slaac-renum

On 21-May-20 14:17, Owen DeLong wrote:
> 
> 
>> On May 20, 2020, at 19:10 , Fernando Gont <fgont@si6networks.com <mailto:fgont@si6networks.com>> wrote:
>>
>> Hello, Philip,
>>
>> On 20/5/20 05:55, Philip Homburg wrote:
>>>>> In my opinion, L-15 needs to be a SHOULD NOT or otherwise have space
>>>>> for the operator of the router to override this behavior. I have provided
>>>>> a use case for that in the past.
>>>>
>>>> These are requirements for the CPE, not for the operator. i.e., what the
>>>> CPE is expected to do without human intervention. It would seem to me
>>>> that, in that light the current "MUST" conveys the meaning of "if you
>>>> don't follow this, you are breaking things".  A device that employs
>>>> local addresses for more than the leased time may potentially employ
>>>> addresses for longer than valid.
>>> I think the need to relax L-15 comes from the fact that ISPs have an
>>> incentive to use very short lease times.
>>> I don't know the details, but what seems to happen is that when a
>>> customer swaps one CPE for anothor, the old CPE doesn't release the
>>> lease (i.e., people just poweroff or disconnect the old CPE).
>>> Then when the new CPE asks for a lease and the customer has a fixed
>>> prefix, the radius daemon finds that the lease is already in use by
>>> the old CPE and doesn't give any lease to the new CPE.
>>> The hacky quick fix for this is to set lifetimes in the lease to only
>>> a few hours at most and ask people to wait.
>>
>> In that case, how would the new CPE get its packets, anyway? I don't seem to see what you'd be "fixing" by manually extending the lifetimes.
> 
> As silly as it seems to you and me, he wants the LAN to continue to function while disconnected by misconfiguring his router.

I think that is why we invented ULAs. At least, RFC 4193 starts out by stating that ULAs are "intended for local communications."

It's a shame that draft-ietf-v6ops-ula-usage-considerations never made it. "The benefit is to ensure stable and specific local communication regardless of the ISP uplink failure."

    Brian

>>> We have to be careful, that we don't reserve the term CPE for
>>> 'device used by a customer who doesn't know any better'.
>>> Historically, we allow operators of routers to set all kinds of parameters
>>> even if they would shoot themselves in the foot doing that. So the CPE
>>> specs are useful set of specifications to connect a router to a DSL or
>>> cable connection. But that doesn't mean we should prevent to owner of the
>>> CPE from configuring the local network as that person sees fit.
>>
>> The recommendations in this document have to do with what the CE Router does, by default, without human intervention.
>>
>> We're not precluding CE Routers to have other knobs to do other things.
>>
>> So I fail to see why you say L-15 should be "relaxed". -- L-15 is not arguing that you should or should not manually configure stuff in your CE Router.
> 
> I suspect he’s interpreting it (and some vendors are not unlikely to as well) to say that vendors should not allow this misconfiguration.
> 
> Perhaps if we add the words “by default” or something like that into the language to make it clear that this specifies only the required default behavior
> fo the CE Router and does not preclude knobs allowing one to misconfigure their device to obtain a desired result it would address his singular concern
> without relaxing the requirement to the point of doing substantial damage elsewhere.
> 
> Owen
> 
> 
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