North American Network Operators Group

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RE: The Choice: IPv4 Exhaustion or Transition to IPv6

  • From: michael.dillon
  • Date: Sun Jul 01 17:41:57 2007

> - that less than 50% of the v4 space is currently routed. 
> scarcity will presumably cause these non-routed blocks to be:
>  :- used and routes
>  :- reclaimed and reassigned
>  :- sold on

Uh, no. Just because the address space is not visible in the public
Internet's default free zone does not mean that it is sitting on a shelf
in a dusty warehouse. Most of that space is actively in use by
organizations who explicitly want an IP internetwork that is
disconnected from the Internet, or by organizations who can achieve
multihomed connectivity from two upstreams without needing their routes
to be propogated between those upstreams. This kind of thing happens way
out at the edges of the network, far from the core, where two upstreams
maintain peering links (possible at a local Internet exchanges).

So to sum up. They are used and routed already. They cannot be reclaimed
since they are fully justified. And they can't be sold because they are
used for mission critical networks.

> - that much of the space in use within organisations could be 
> optimised
>  :- mop up unused gaps in subnet

This will cause routing table scaling problems inside organizations,
exacerbated by the greater amount of legacy hardware found in such

--Michael Dillon