Re: [homenet] homenet-prefix-assignment update - behaviour at one ISP

[Ted Lemon <[e-mail]>]

You guys are debating points that are long-since decided.

On Oct 8, 2014, at 8:29 AM, Alexandru Petrescu <[e-mail]> wrote:

> Le 08/10/2014 14:15, Pierre Pfister a écrit :
>> 
>> Le 8 oct. 2014 à 13:58, Alexandru Petrescu
>> <[e-mail]> a écrit :
>> 
>>> Hi Pierre,
>>> 
>>> Le 08/10/2014 13:28, Pierre Pfister a écrit :
>>>> Hi Alex,
>>>> 
>>>> Reply is inlined,
>>>> 
>>>> Le 8 oct. 2014 à 12:09, Alexandru Petrescu
>>>> <[e-mail]> a écrit :
>>>> 
>>>>> Hi Pierre,
>>>>> 
>>>>> Thanks for the draft update.  Now I have two questions:
>>>>> 
>>>>>> prefixes of size 64 are RECOMMENDED.
>>>>> 
>>>>> Why is this length recommended?  I think it may be because of
>>>>> Ethernet?
>>>> 
>>>> I’m not a big fan of putting 64s everywhere neither. And I
>>>> strongly disagree with mandating 64 bit long prefixes. The prefix
>>>> algorithm itself is agnostic on this side.
>>>> 
>>>> Nevertheless, some parts of this document are home-network
>>>> specific. Not even talking about crappy implementations, home
>>>> network links should support SLAAC whenever possible. Which is
>>>> the reason why using 64bit long prefixes is RECOMMENDED.
>>> 
>>> Ah, I see.  I doubt though SLAAC is 64.  Maybe Ethernet is.
>> 
>> SLAAC relies on ‘interface identifier’. Ethernet uses the EUI-64. I
>> have no knowledge of other methods of generating an interface
>> identifier.
>> 
>> The why64 draft is interesting (and sad) on that front.
>> 
>>> 
>>>> But smaller prefixes are better than *no prefix at all*. When
>>>> there are not enough prefixes available (e.g. the ISP provides a
>>>> single 64 while we have multiple links), smaller prefixes can be
>>>> used (80 for instance). Which means dhcpv6 must be used. Our
>>>> implementation supports it, and it works with my laptop.
>>> 
>>> Ok.
>>> 
>>>> But again, that should be avoided whenever possible. And ISPs
>>>> MUST provided enough prefixes (IMO).
>>> 
>>> I agree with you.
>>> 
>>> Last time I checked Free ISP seems to provide 8 /64 prefixes to my
>>> homenet: 2001:db8:0:ce10::/64 2001:db8:0:ce11::/64 ...
>>> 2001:db8:0:ce17::/64 I dont think these could be aggregated into a
>>> single shorter prefix, or my math is missing.
>> 
>> That is 2001:db8:0:ce10::/61
> 
> Right, sorry, my math was missing.  So I suppose Free ISP delegates a
> single /61 to me then, not several /64s.  This is a local prefix
> division performed in that router.  I do not necessarily agree with it,
> as I could have divided it differently, or I could have announced the /61 in RA in the first link of the homenet, etc.