RFC 2063 (rfc2063) - Page 3 of 37

Traffic Flow Measurement: Architecture

RFC 2063         Traffic Flow Measurement: Architecture     January 1997


   The architecture specifies common metrics for measuring traffic
   flows.  By using the same metrics, traffic flow data can be exchanged
   and compared across multiple platforms.  Such data is useful for:

     - Understanding the behaviour of existing networks,

     - Planning for network development and expansion,

     - Quantification of network performance,

     - Verifying the quality of network service, and

     - Attribution of network usage to users.

   The traffic flow measurement architecture is deliberately structured
   so that specific protocol implementations may extend coverage to
   multi-protocol environments and to other protocol layers, such as
   usage measurement for application-level services.  Use of the same
   model for both network- and application-level measurement may
   simplify the development of generic analysis applications which
   process and/or correlate any or all levels of traffic and usage
   information.  Within this docuemt the term 'usage data' is used as a
   generic term for the data obtained using the traffic flow measurement
   architecture.

   This document is not a protocol specification.  It specifies and
   structures the information that a traffic flow measurement system
   needs to collect, describes requirements that such a system must
   meet, and outlines tradeoffs which may be made by an implementor.

   For performance reasons, it may be desirable to use traffic
   information gathered through traffic flow measurement in lieu of
   network statistics obtained in other ways.  Although the
   quantification of network performance is not the primary purpose of
   this architecture, the measured traffic flow data may be used as an
   indication of network performance.

   A cost recovery structure decides "who pays for what." The major
   issue here is how to construct a tariff (who gets billed, how much,
   for which things, based on what information, etc).  Tariff issues
   include fairness, predictability (how well can subscribers forecast
   their network charges), practicality (of gathering the data and
   administering the tariff), incentives (e.g.  encouraging off-peak
   use), and cost recovery goals (100% recovery, subsidisation, profit
   making).  Issues such as these are not covered here.

   Background information explaining why this approach was selected is
   provided by 'Traffic Flow Measurement:  Background' RFC [1].



Brownlee, et. al.             Experimental