large multi-site enterprises and PI prefix [Re: who gets a /32 [Re: IPV6 renumbering painless?]]

Sun Nov 21 14:57:24 UTC 2004

I think this is important point that needs to be called out 
explicitly.

On Sat, 20 Nov 2004, Iljitsch van Beijnum wrote:
> On 19-nov-04, at 17:58, Stephen Sprunk wrote:
>>> 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?
>
> That's right. If you need internet access, you need it to be faster than 16 
> kbps. As far as I can tell, it's pretty rare for an organization of this size 
> to have their own IP network that they use to connect all their sites to the 
> global internet, for the simple reason that leased lines, framerelay or ATM 
> capacity is generally more expensive than IP connectivity.
>
> So a single large address block is of little use to such an organization, 
> unless they get to announce more specifics all over the place.

If we reword the last sentence to include the use of ULA addresses, to 
be like:

   So a single, globally routable large address block is of little use
   to such an organization, unless they get to announce more specifics
   all over the place.

This seems to imply several things:
  - when having lots of sites, you typically want to obtain local
    Internet connectivity, because transporting all the traffic over
    links or VPNs is a pretty heavy business
    * though at least the smallest sites are also likely to be solely
      obtain their connectivity using VPNs through centralized
      firewalls etc.
  - you don't want to backhaul all the traffic in the internal network
    / VPNs, so you'll either need to announce a lot of more specifics
    or use IP addresses from local internet providers
  - giving those big enterprises globally routable PI will make it much
    more lucrative for them to request allowing the more specifics from
    their upstreams, etc., thus getting us to the more specific mess.

Therefore, if we'd like to to prevent the more specific 
multihoming/traffic engineering mess we have with v4, most of those 
big enterprises don't really seem to need globally routable PI space, 
provided that they can already use ULAs if they want.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings