[bcop] IPv6 deployment for small residential providers

Hi William, 


On 09 Nov 2014, at 12:47, William Waites <wwaites at tardis.ed.ac.uk> wrote:

> I've started writing here:
> 
>    https://pad.okfn.org/p/bcop-small-ipv6
> 
> Today, a couple of paragraphs about the intended audience before
> getting into the meat of it.
> 
> -w
> 

Thanks, a good start. Just one comment:
"they also need ipv4 addresses to use as router-id (need not be
global, but need to be unique).” is not true. 

It needs to be a 32-bit number, but it doesn’t have to be an IPv4 address. 

This should be made clear, as I notice in our training courses, a lot of engineers seem to think that the router ID MUST be an IPv4 address, while it normally is, 
it is not mandatory. 0.0.0.1 is a valid router-ID, I believe. In an IPv6-only network, for example, when you have no IPv4 addresses, you can just make something 32-bitty up and use that as the router ID. 

On the address assignment: What we see and hear in practice in our courses, is assign something on 4-bit boundary, big enough to cater for the next 10 years. 
So: a /64 only if you are absolutely sure that the customer will never come back for one more subnet (not likely).
a /60 (if you are conservative)
a /56 (most common for residential users)
a /52 (we see this in some cases for both residential customers and business customers)
a /48 (for business customers, or for residential customers if you are generous, and have a one-size-fits-all-approach)

I hope this helps,

Cheers,

Nathalie