[Georgia Tech][GVU][Research][Search]
[Eye Graphic]

Estimates of Number of Services
that Use Default Ports

Introduction

Since the statistics collected by MERIT NIC Services examine which port the traffic is generated on, inferring the actual source of the service can be problematic. That is, event hough Gopher servers by default are to run on port 70, not all Gopher servers do. The same applies for WWW and Z.39.50 servers. As a result, generalizing and basing conclusions upon the numbers collected must take into account the following information:

Gopher Servers:

As of April 1994, the total number of gopher servers accessible on the Internet was 6958. However, only something like 2927 were found to be running on port 70. These number were collected by the Veronica harvester operated by Steven Foster and were presented at GopherCON '94. As a result, maybe only about 42% the Gopher traffic is measured on port 70.

Hypertext Transfer Protocol, or World-Wide Web Servers:

As of January 1994, approximately 78% of the servers being run were being operated on port 80. These numbers were collected from the First WWW User Survey(January 1994). However, based upon the port numbers extracted from Matthew Gray's Comprehensive HTTP Site List(July 1994), some 89% of the servers were operating on port 80. Additionally, the Second WWW User Survey (November 1994) reports that 87% of the participants replied that their server listened to port 80.

Remaining Warnings

First, even if the numbers collected by MERIT NIC Services are scaled by the above factors to account for traffic generated on non default ports, the underlying assumption, which may not be valid, asserts that all servers on all ports generate an equal amount of traffic. Yet we know that for example, the World Cup Soccer Information runs on port 80 and gets over 100,000 requests some days. This can be used to argue against the above assumption of equal data generation across ports.

Second, the above percentages are for servers not clients. WWW clients are able to access many protocol, using the server's native ports. That is, when a WWW client makes an anonymous ftp connection, the traffic is counted to ports 20 and 21, not to port 80. Hence, the increased use of WWW clients most likely results in increased use of other network-based resources like Gopher and FTP.

James Pitkow
Graphics, Visualization and Usability Center
Georgia Institute of Technology
pitkow@cc.gatech.edu