Re: A common problem with SLAAC in "renumbering" scenarios

[Simon Hobson <[e-mail]>]

Mark Smith <[e-mail]> wrote:

> I don't know about other markets, however dynamic IPv4 addresses on
> permanent, always up broadband links in Australia has usually been
> because ISPs wanted to charge a price premium for static address
> assignments..

That's the case in the UK as well. From my dealings with various of them over the years (with work hat on) I have come across a number of variations.
BT charges (or did last time I had any dealings) £5/mo for a single static IPv4 address - that may be a premium of as much as 15-20% but obviously less on a more expensive product. Since they run static and dynamic assignments on the same set of equipment/connections, and with permanent-on connections there's no IPv4 address saving with dynamic addressing, there's no technical reason to charge a monthly premium other than "because we can and it boosts profit margins".
TalkTalk does not allow static IPv4 on residential products, but does on business products. Naturally business products cost more, although they use the same set of infrastructure - so it's a purely marketing thing to stop a business that doesn't need a static IPv4 (or the slightly better service levels) paying less by using a "residential" product.

So yes, I think it's safe to assume that there's a strong profit driver towards doing anything that makes life "difficult" for any customer wanting a static address/prefix - eg for hosting services or running site-site VPNs. A lot of this is down to the competitive market we "enjoy" in the UK with a significant race to the bottom in terms of pricing among many of the ISPs - so anything that can lower the headline "from £xx" on adverts, while making it up on extras, is used. I don't expect IPv6 to be different if you want stable addressing.
So yes, I think the earlier reference to RFC 1925 (I'd forgotten about that one), section 2.3, is appropriate if pushing for stable addressing to be the norm.

Other ISPs are more reasonable. My own, Plusnet, charges a one-off setup when requesting a (single) static IPv4 and no premium thereafter.