was bogon filters, now "Brief Segue on 1918"

Joel Jaeggli joelja at bogus.com
Wed Aug 6 13:49:14 CDT 2008

Darden, Patrick S. wrote:
> I'll reply below with //s.  My point is still: most companies do not use RFC1918 correctly. 

As with say v4 prefix distribution as a whole where you observe that the 
number of very large prefix holders is rather small,  it's really easy 
to say most casually, trivially in fact, that most rfc1918 uses are 
single devices with a single subnet behind them. There are a small 
number (low tens of thousands instead of low hundreds of millions) of 
applications where rfc1918 space feels rather tight, because in fact 
it's all going to get used. you don't have to look very far for 
operators (what we traditionally thing of as operators represent a chunk 
of those applications) chaffing under their 1918 limitations, see for 
example this draft which is undoubtedly met with opposition since the 
idea has come around before.


> Your point seemed to be that it is not a large enough allocation of IPs for an international enterprise of 80K souls.  My rebuttal is: 16.5 million IPs isn't enough?

That is my point, 24 bits is rather tight. The least specific 32 of 96 
bits looks like it will continue to work ok for some time...

> --p
> -----Original Message-----
> From: Joel Jaeggli [mailto:joelja at bogus.com]
> Sent: Wednesday, August 06, 2008 1:31 PM
> To: Darden, Patrick S.
> Cc: nanog at nanog.org
> Subject: Re: was bogon filters, now "Brief Segue on 1918"
> That's comical thanks. come back when you've done it.
> //Ok.
> Marshall is correct.
> //Ok.
> If you'd like to avoid constant renumbering you need a sparser 
> allocation model.  You're still going to have collisions with your 
> suppliers and acquisitions and some applications (eg labs, factory 
> automation systems etc) have orders of magnitude large address space 
> requirements than the number of humans using them implies.
> //You used the metric of 80K people.  Now you say it is a bad metric when I reply using it.  Your fault, you compound it--you don't provide a better one.  What are we talking about then?  100 IPs per person--say each person has 10 PCs, 10 printers, 10 automated factory machines, 10 lab instruments, 49 servers and the soda machine on their network?  80,000*100==8 million IP addresses.  That leaves you with 8.5 million....  And that includes 80,000 networked soda machines.  I don't think you have that many soda machines.  Even on 5 continents.  Even with your growing Asian market, your suppliers, and the whole marketing team.
> In practice indivudal sites might be assigned between a 22 and a 16 with 
> sites with exotic requirements having multiple assignments potentially 
> from different non-interconnected networks (but still with internal 
> uniqueness requirements).
> //Err.  Doing it wrong does not justify doing it wrong.

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