Re: IPv6 fc00::/7 — Unique local addresses

Thu Oct 21 08:42:23 UTC 2010

On Oct 20, 2010, at 10:07 PM, Mark Smith wrote:

> On Thu, 21 Oct 2010 06:38:33 +0200
> Graham Beneke <graham at apolix.co.za> wrote:
> 
>> On 21/10/2010 03:49, Matthew Kaufman wrote:
>>> On 10/20/2010 5:51 PM, Owen DeLong wrote:
>>>> 
>>>> Part 2 will be when the first provider accepts a large sum of money to
>>>> route it within their public network between multiple sites owned by
>>>> the same customer.
>>> 
>>> Is this happening now with RFC 1918 addresses and IPv4?
>> 
>> I have seen this in some small providers. Doesn't last long since the 
>> chance of collision is high. It then becomes a VPN.
>> 
>>>> Part 3 will be when that same provider (or some other provider in the
>>>> same boat) takes the next step and starts trading routes of ULA space
>>>> with other provider(s).
>>> 
>>> Is this happening now with RFC 1918 addresses and IPv4?
>> 
>> I've seen this too. Once again small providers who pretty quickly get 
>> caught out by collisions.
>> 
>> The difference is that ULA could take years or even decades to catch 
>> someone out with a collision. By then we'll have a huge mess.
>> 
> 
> I don't think there is a difference. The very small providers are
> the ones who make the stupid mistakes, it's the larger ones that do the
> right thing because it is in their operational interests. Operational
> competence, and the resulting increased reliability, is one of the
> attributes customers of ISPs value highly.
> 
> If any of the Tier-1s don't route ULA address space, then it is useless
> compared to global addresses that *are* routed by *all* the Tier-1s. As
> the Tier-1s also hire competent networking people, they'll also
> understand the scaling issues of the ULA address space, and why it
> shouldn't be globally routed. Competent networking people also exist at
> the lower tiers as well.
> 
Ah, but, since statistically probable Uniqueness is present, I'm betting
eventually some combination of Tier-1s will get bought off to route ULA
and then the flood gates open.

Tier-1s are famous for having their sales and accounting departments
override good engineering practices on a somewhat regular basis.

With RFC-1918 this couldn't happen because collisions meant it
simply wouldn't work. ULA has no such impediment.

> If operators just blindly accept and implement what sales people tell
> them to, then those operators aren't operators. They're mindless drones
> - and the rest of the people operating the Internet will protect the
> Internet from them. Darwin eventually gets rid of those operators
> and the ISP that employ them.
> 
There's a difference between blind acceptance and adherence to a
direct overriding order from the guy that signs your paycheck. I'm sure
they will attempt to fight the good fight, but, in the end, $$ tend to trump
good engineering unless what the $$ want simply can't be made to work.

> Since ULAs could be used as DoS attack sources, they'll also likely be
> filtered out by most people as per BCP38.
> 
Maybe... Given what I've seen with RFC-1918 and other BCP38 violations,
I lack your faith.

Owen