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Re: I-D Action:draft-ietf-v6ops-ipv6-cpe-router-03.txt
On 2009-12-19 18:42, Mark Smith wrote:
> On Fri, 18 Dec 2009 09:09:21 -0800
> Fred Baker <fred@cisco.com> wrote:
>
>> I will open a WGLC on this after new years; My mind will be elsewhere
>> for the coming two weeks, I imagine yours will as well. However, if
>> you want to start reading/commenting now...
>>
>
> Maybe I'm being a bit overly paranoid about people being precious with
> IPv6 address space, however, the last sentence of -
>
>
> "WPD-1: The IPv6 CE router MUST support DHCP prefix delegation
> requesting router behavior as specified in [RFC3633] (IA_PD
> option). The IPv6 CE router MUST ask for a prefix large
> enough to cover all of its LAN interfaces."
>
> could be interpreted to mean that the ISP only needs to provide a
> prefix to meet the requested size e.g. for two LAN interfaces a /63.
> That would seem to me to be encouraging an "only enough" address space
> model, rather than a "more than enough" address space model, which is
> what I think IPv6 is aiming at.
Without disagreeing with anything Barbara Stark said, I'm wondering
why the last sentence of WPD-1 is there at all. I mean, why would
an implementer ever ask for too little address space?
>
> There might be some value in stating that it is likely that an ISP will
> delegate a prefix that not only meets this minimum requirement but also
> allows for a number of additional subnets downstream of the CPE, with
> the delegated prefix size likely significantly larger, possibly a /48
> or /56. IOW, stating that the delegated prefix will likely be larger
> than what is requested (not that it is probably likely, but I could see
> a CPE vendor adding in a check to see if the delegated prefix size was
> equal to that requested, and if it didn't, not using it).
So if there is anything to say, it's that the CE MUST ask for at least
one /64 per interface and MUST be configurable to ask for more.
Brian