RFC 1273 (rfc1273) - Page 2 of 8

Measurement Study of Changes in Service-Level Reachability in the Global TCP/IP Internet: Goals, Experimental Design, Implementation, and Policy Considerations

RFC 1273                  A Measurement Study              November 1991


   study to measure changes in Internet service-level reachability over
   a period of one year.  The study considers upper layer service
   reachability instead of basic IP connectivity because the former
   indicates the willingness of organizations to participate in inter-
   organizational computing, which will be an important component of
   future wide area distributed applications.

   The data we gather will contribute to Internet research and
   engineering planning activities in a number of ways.  The data will
   indicate the mechanisms sites use to distance themselves from
   Internet connectivity, the types of services that sites are willing
   to run (and hence the type of distributed collaboration they are
   willing to support), and variations in these characteristics as a
   function of geographic location and type of institution (commercial,
   educational, etc.).  Understanding these trends will allow
   application designers and network builders to more realistically plan
   for how to support future wide area distributed applications such as
   digital library systems, information services, wide area distributed
   file systems, and conferencing and other collaboration-support
   systems.  The measurements will also be of general interest, as they
   represent direct measurements of the evolution of a global electronic
   society.

   Clearly, a study of this nature and magnitude raises a number of
   potential concerns.  In this note we overview our experimental
   design, considerations of network and remote site load, mechanisms
   used to control the measurement collection process, and our efforts
   to inform sites measured by this study, along with concomitant
   network appropriate use and privacy issues.

   A point we wish to stress from the outset is that this is not a study
   of network security.  The experiments do not attempt to probe the
   security mechanisms of any machine on the network.  The study is
   concerned solely with the evolution of network connectivity and
   service reachability.

Experimental Design

   The study consists of a set of runs of a program over the span of one
   to two days each month, repeated bimonthly for a period of one year
   (in January 1992, March 1992, May 1992, July 1992, September 1992,
   and November 1992).  Each program run attempts to connect to 13
   different TCP services at each of approximately 12,700 Internet
   domains worldwide, recording the failure/success status of each
   attempt.  The program will attempt no data transfers in either
   direction.  If a connection is successful, it is simply closed and
   counted.  (Note in particular that this means that the security
   mechanism behind individual network services will not be tested.)



Schwartz