who gets a /32 [Re: IPV6 renumbering painless?]

Fri Nov 19 16:58:25 UTC 2004

Thus spake "Iljitsch van Beijnum" <iljitsch at muada.com>
> On 18-nov-04, at 18:02, Jeroen Massar wrote:
>> Larger enterprises probably consist of 200 'sites' already, eg seperate
>> offices, locations etc. Thus they can, after becoming a LIR and getting
>> an ASN, which most of the time they already have, easily get a /32.
>
> Jeroen, this is nonsense and you know it.
>
> We've been discussing the big enterprise problem in multi6 (multihoming in 
> ipv6) circles very extensively. At some point, I realized that the "I'm so 
> huge I need private space" claim is false in 99% of all cases, as these 
> organizations tend to have multiple sites (as you indicate above) but they 
> generally do not have real connectivity between those sites. This means a 
> single large prefix won't do them much good, and basically they're no 
> different than a bunch of smaller single-site organizations.

Don't have "real connectivity"?  I've personally worked with dozens of 
Fortune 500 companies that have internal FR/ATM networks that dwarf AT&T, 
UUnet, etc. in the number of sites connected.  Thousands of sites is common, 
and tens of thousands of sites in some cases.  Do you not consider these 
networks "real" because each site may only have a 16k PVC to talk to 
corporate?

However, since the _vast_ majority of communication is internal and all but 
a dozen hosts are hidden behind a NAT, nobody on the public Internet has any 
clue these networks exist.  Even 10/8 is barely big enough to hold the 
largest of these, and in one case we had to use multiple instances of 10/8 
with separate servers in each instance to allow for growth in the number of 
hosts at each site (or sites themselves) and handle protocols which were not 
compatible with NAT.

ULAs are one way to solve these sorts of problems (and many others), and PI 
space is another.  Guess which one companies would prefer, given the cost 
and paperwork levels involved with each and the lack of any need for 
external communication?

> Now I hate to be the bearer of bad news, but having unaggregatable 
> globally routable address space just doesn't scale and there are no 
> routing tricks that can make it scale, whatever you put in the IP version 
> bits, so learn to love renumbering. And again, IPv6+NAT makes no sense as 
> NAT works much better with IPv4 and with NAT you don't really need the 
> larger address space.

If I have a disconnected network, why would I use NATs or be forced to 
renumber periodically?  Why should disconnected networks use global 
addresses (and pay rent to the RIRs) in the first place?

ULAs are not about enabling NAT in IPv6.

S

Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking 