RFC 2721 (rfc2721) - Page 3 of 10

RTFM: Applicability Statement

RFC 2721             RTFM: Applicability Statement          October 1999


   [RTFM-NEW] RTFM New Attributes                         (Experimental)

      There has been considerable interest from users in extending the
      RTFM Architecture so as to allow a meter to report on an increased
      number of flow-related measures.  This RFC documents work on
      specifying such measures (the 'new' attributes) and reports on
      experience of implementing them.

   [RTFM-NTM] RTFM: Experiences with NeTraMet            (Informational)

      NeTraMet is a free software implementation of the RTFM
      Architecture which has been available since 1993.  This RFC
      records RTFM implementation experience gained with NeTraMet up to
      late 1996.  One particularly important result is the realisation
      that groups of rules which test the same attribute using the same
      mask can be implemented as a single hashed comparison, allowing
      the meter to rapidly determine whether a packet belongs to one of
      a large number of networks.

2  Brief Technical Specification (TS)

   RTFM provides for the measurement of network traffic 'flows', i.e.

   - a method of specifying traffic flows within a network
   - a hierarchy of devices (meters, meter readers, managers) for
     measuring the specified flows
   - a mechanism for configuring meters and meter readers, and for
     collecting the flow data from remote meters

   RTFM provides high time resolution for flow first- and last-packet
   times.  Counters for long-duration flows may be read at intervals
   determined by a manager.  The RTFM Meter is designed so as to do as
   much data reduction work as possible, which minimizes the amount of
   data to be read and the amount of processing needed to produce useful
   reports from it.

   RTFM flow data can be used for a wide range of purposes, such as
   usage accounting, long-term recording of network usage (classified by
   IP address attributes) and real-time analysis of traffic flows at
   remote metering points.

3  Applicability Statement (AS)

   To use RTFM for collecting network traffic information one must first
   consider where in the network traffic flows are to be measured.  Once
   that is decided, an RTFM Meter must be installed at each chosen
   measurement point.




Brownlee                     Informational