RFC 2139 (rfc2139) - Page 3 of 25

RADIUS Accounting

RFC 2139                   RADIUS Accounting                  April 1997


      Network Security

         Transactions between the client and RADIUS accounting server
         are authenticated through the use of a shared secret, which is
         never sent over the network.

      Extensible Protocol

         All transactions are comprised of variable length Attribute-
         Length-Value 3-tuples.  New attribute values can be added
         without disturbing existing implementations of the protocol.

1.1.  Specification of Requirements

   In this document, several words are used to signify the requirements
   of the specification.  These words are often capitalized.

   MUST      This word, or the adjective "required", means that the
             definition is an absolute requirement of the specification.

   MUST NOT  This phrase means that the definition is an absolute
             prohibition of the specification.

   SHOULD    This word, or the adjective "recommended", means that there
             may exist valid reasons in particular circumstances to
             ignore this item, but the full implications must be
             understood and carefully weighed before choosing a
             different course.

   MAY       This word, or the adjective "optional", means that this
             item is one of an allowed set of alternatives.  An
             implementation which does not include this option MUST be
             prepared to interoperate with another implementation which
             does include the option.

1.2.  Terminology

      This document uses the following terms:

   service   The NAS provides a service to the dial-in user, such as PPP
             or Telnet.










Rigney                       Informational