IAB and "private" numbering

Thu Nov 17 16:44:10 UTC 2005

On 15.11 07:38, Mark Smith wrote:
> 
> RFC1627, "Network 10 Considered Harmful (Some Practices Shouldn't be
> Codified)" and RFC3879, "Deprecating Site Local Addresses" provide some
> good examples of where duplicate or overlapping address spaces cause
> problems, which is what happens when different organisations use RFC1918
> addresses, even if they aren't connected to the Internet.

This is practical engineering, not theoretical science.  Practical
engineering is about *trade-offs*. 

We were seeing address space requests for huge deployments with a real
low probability to ever be routed anywhere beyond a quite local domain. 
There are huge deployments of this kind now and happily so without
unnecessary using finite address resources. 

The drawbacks were known and discussed.  Note that 1627<1918.  Clear
warnings were written into 1918; it is one of the more "operational"
RFCs, certainly at the time.  We also discussed the possibility of NATs
but it was out-of-scope for 1918; we discussed application layer
gateways though; we did not anticipate any NAT deployments beyond a very
local scale. 

Would we rather have run out of unallocated unique IPv4 address space at
some point in the past?  Would an alternative  have been ready by then? 

(Would we rather run out of unallocated IPv4 address space on -say- 31-Dec-2005? 
Will IPv6 be ready for prime time then?)

Daniel 
One of the instigators and co-author of RFC1918. 