How large is the Internet?

The short answer is that we don't know. Mark Lottor, in is Internet domain survey counted 4,852,000 Internet hosts declared in the Internet domain name service in January 1995. At the same time, a similar search was conducted in Europe. The results reported by Mirjam Kuehne indicated a total of 1,029,270 hosts in Europe at that time. The most recent report from RIPE shows that there were more than 1.5 million hosts in Europe in may 1995.

The number of hosts is indeed only an indication of the actual size of the Internet. Going from "number of hosts" to "number of users" is equivalent to taking a satellite picture of a city, counting the number of houses and buildings and guessing the number of inhabitants, which is not exactly a very precise process. The host number is on the other hand the only number which can be easily obtained. It allows us to gauge the growth of the network. In fact, raging arguments have been exchanged on the "size of the Internet" issue. The Internet Society maintains a set of charts which describe the network's growth.

Is it mostly US?

Mark Lottor provides a listing of hosts per domain, which we can use to provide an estimate of the number of hosts in the US: 
 com      1316966  
 edu      1133502  
 gov       209345  
 mil       175961  
 net       150299  
 org       154578  
 us         37615 
----------------- 
 total    3178266
We should indeed be aware that several European comanies, networks and associations are registered under "com", "edu" or "org", but we will use the available figure nevertheless. This gives an estimate of the Internet spread: Back to the point of whether the Internet is "mainly US" and whether "Europe is five years behind". The US component is certainly the largest (65%) but you can expect a million of hosts in Europe to contribute some traffic. If we look at past statictics, we observe that the US component of the Internet included about 1 million hosts in July of 1993, i.e. 18 months before the same number was reached in Europe. This figure of 18 months give the advance of the US over the average European country. We should however note that the situation varies largely from country to country. Holland and Finland, for example, have both twice more Internet hosts per head than the US. And the European count grew from 1 million to 1.4 in the 1st semester of 1995.

Christian Huitema