[e2e] Proposing the Sathiaseelan-Partridge Law of Mice and Elephants

David P. Reed dpreed at reed.com
Fri Mar 23 08:50:46 PDT 2007

Another reaction is that "fixed size fields" always get us into 
trouble,so we should never define a fixed size without indexing it 
temporally.   I always regret the IP protocol chose 32-bit addresses of 
type A, B, and C got us NAT boxes that are now viewed as "good things" 
even as they balkanize the Internet, destroying the Internet's universal 
goal of interoperability and interconnectivity.

So we should be careful about picking any number.   One possibility is 
to pick a "law" to generate the number.

If Craig is right that the correct number was 64 bytes in 1991, and 
Arjun's right that 576 is the right number in 2007, let's assume it's an 
exponential, and the result we get is:

N = 2 ^ [6 + (1/8 * log 3) * (Y - 1991)]

I propose we call this "Sathiaseelan-Partridge Law of Mice and Elephants".

All protocol engineers can thus tune their work and measurements can be 
indexed to this growth law.  The Internet economic process can use it to 
design its roadmap of protocol field size evolution.   Etc.

It may be extremely helpful to know that the doubling time of packet 
distinctions is predictable.   Moore's Law is 18 months.   
Sathiaseelan-Partridge predicts mouse-scale packet doubling every 61 
months or so.

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