Estimating the size of the Bitcoin network

[disclosure]

Hi folks,

As part of my attempt to learn more of the Bitcoin protocol and also to get at a rough estimate of the current size of the Bitcoin network, I've started working on https://github.com/ayeowch/bitnodes.

The project is essentially a Python script that sends out getaddr (https://en.bitcoin.it/wiki/Protocol_specification#getaddr) message to all peering nodes in a recursive manner to find all the nodes in the network. It is far from complete as I have yet to arrive at a final number myself but I am sending this out anyway to get more feedbacks and also to share with those that may be interested on this metric as well.

[intr0]

intriguing.

[solex]

This is a great project because it researches one of the key metrics needed in the ongoing debate about scalability. For example, one of the persistent objections to raising the max block size limit is that it may decentralize the network. If there were regular stats showing the number of peering nodes then the growth or decline in their number can be plotted against average blocksize as well as latency in block propagation.

Could there be a useful measure analogous to kilowatt hours, which is the number of active nodes per hour?

Good luck with this idea, disclosure.