How big is the Internet?

Patrick W. Gilmore patrick at
Thu Aug 15 18:27:36 UTC 2013

On Aug 15, 2013, at 10:05 , Leo Bicknell <bicknell at> wrote:
> On Aug 14, 2013, at 3:27 PM, Patrick W. Gilmore <patrick at> wrote:

>> Once you define what you mean by "how bit is the Internet", I'll be happy to spout off about how big it is. :)
> Arbitrary definition time: A Internet host is one that can send and receive packets directly with at least one far end device addressed out of RIR managed IPv4 or IPv6 space.
> That means behind a NAT counts, behind a firewall counts, but a true private network (two PC's into an L2 switch with no other connections) does not, even if they use IP protocols.  Note that devices behind a pure L3 proxy do not count, but the L3 proxy itself counts.
> Now, take those Internet hosts and create a graph where each node has a binary state, forwards packets or does not forward packets the result is a set of edge nodes that do not forward packets.  The simple case is an end user PC, the complex case may be something like a server in a data center that while connected to multiple networks does not forward any packets, and is an edge node on all of the networks to which it is attached.
> To me, "all Internet" traffic is the sum of all "in" traffic on all edge nodes.  Note if I did my definition carefully out = in - (packet loss + undeliverable), which means on the scale of the global Internet I suspect out == in, when rounded off.

I have a feeling you flipped "in" & "out" in that formula.

> So please, carry on and spout off as to how big that is, I think an estimate would be very interesting.

Spout off time:

My laptop at home is an edge node under the definition above, despite being behind a NAT. My home NAS is as well. When I back up my laptop to my NAS over my home network, that traffic would be counted as "Internet" traffic by your definition.

I have a feeling that does not come close to matching the mental model most people have in their head of "Internet traffic". But maybe I'm confused.


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