estimation of number of DFZ IPv4 routes at peak in the future

Mikael Abrahamsson swmike at
Tue Mar 8 21:17:35 CST 2011


We had an interesting discussion the other day at work. We were 
speculating on how many DFZ IPv4 routes there would be at peak in the 
future before it starts to decline again due to less IPv4 usage. The 
current number is around 350k, and my personal estimation is that it would 
grow by at least 100k more due to the the last 5 /8s being carved up at 
around /22 meaning each /8 ending up with 16k routes, plus the last 
allocations being seen in the remaining RIR "normal allocations" would be 
smaller than before plus de-aggregation of space as people "sell" or 
"lease" subspace of their allocations.

My guess therefore is a peak around 450-500k IPv4 DFZ routes and that this 
would happen in around 3-5 years. I wanted to record this for posterity.

What is your guess, any why?

Mikael Abrahamsson    email: swmike at

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