Authentication, Authorization and Accounting (AAA) Transport Profile
RFC 3539

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• 12

Network Working Group                                           B. Aboba
Request for Comments: 3539                                     Microsoft
Category: Standards Track                                        J. Wood
                                                  Sun Microsystems, Inc.
                                                               June 2003

  Authentication, Authorization and Accounting (AAA) Transport Profile

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document discusses transport issues that arise within protocols
   for Authentication, Authorization and Accounting (AAA).  It also
   provides recommendations on the use of transport by AAA protocols.
   This includes usage of standards-track RFCs as well as experimental
   proposals.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
       1.1.  Requirements Language. . . . . . . . . . . . . . . . . .  2
       1.2.  Terminology. . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Issues in Transport Usage. . . . . . . . . . . . . . . . . . .  5
       2.1.  Application-driven Versus Network-driven . . . . . . . .  5
       2.2.  Slow Failover. . . . . . . . . . . . . . . . . . . . . .  6
       2.3.  Use of Nagle Algorithm . . . . . . . . . . . . . . . . .  7
       2.4.  Multiple Connections . . . . . . . . . . . . . . . . . .  7
       2.5.  Duplicate Detection. . . . . . . . . . . . . . . . . . .  8
       2.6.  Invalidation of Transport Parameter Estimates. . . . . .  8
       2.7.  Inability to use Fast Re-Transmit. . . . . . . . . . . .  9
       2.8.  Congestion Avoidance . . . . . . . . . . . . . . . . . .  9
       2.9.  Delayed Acknowledgments. . . . . . . . . . . . . . . . . 11
       2.10. Premature Failover . . . . . . . . . . . . . . . . . . . 11
       2.11. Head of Line Blocking. . . . . . . . . . . . . . . . . . 11
       2.12. Connection Load Balancing. . . . . . . . . . . . . . . . 12

Aboba & Wood                Standards Track                     [Page 1]
RFC 3539                 AAA Transport Profile                 June 2003

   3.  AAA Transport Profile. . . . . . . . . . . . . . . . . . . . . 12
       3.1.  Transport Mappings . . . . . . . . . . . . . . . . . . . 12
       3.2.  Use of Nagle Algorithm . . . . . . . . . . . . . . . . . 12
       3.3.  Multiple Connections . . . . . . . . . . . . . . . . . . 13
       3.4.  Application Layer Watchdog . . . . . . . . . . . . . . . 13
       3.5.  Duplicate Detection. . . . . . . . . . . . . . . . . . . 19
       3.6.  Invalidation of Transport Parameter Estimates. . . . . . 20
       3.7.  Inability to use Fast Re-Transmit. . . . . . . . . . . . 21
       3.8.  Head of Line Blocking. . . . . . . . . . . . . . . . . . 22
       3.9.  Congestion Avoidance . . . . . . . . . . . . . . . . . . 23
       3.10. Premature Failover . . . . . . . . . . . . . . . . . . . 24
   4.  Security Considerations. . . . . . . . . . . . . . . . . . . . 24
   5.  IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 25
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
       6.1.  Normative References . . . . . . . . . . . . . . . . . . 25
       6.2.  Informative References . . . . . . . . . . . . . . . . . 26
   Appendix A - Detailed Watchdog Algorithm Description . . . . . . . 28
   Appendix B - AAA Agents. . . . . . . . . . . . . . . . . . . . . . 33
       B.1.  Relays and Proxies . . . . . . . . . . . . . . . . . . . 33
       B.2.  Re-directs . . . . . . . . . . . . . . . . . . . . . . . 35
       B.3.  Store and Forward Proxies. . . . . . . . . . . . . . . . 36
       B.4.  Transport Layer Proxies. . . . . . . . . . . . . . . . . 38
   Intellectual Property Statement. . . . . . . . . . . . . . . . . . 39
   Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . 39
   Author Addresses . . . . . . . . . . . . . . . . . . . . . . . . . 40
   Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 41

1.  Introduction

   This document discusses transport issues that arise within protocols
   for Authentication, Authorization and Accounting (AAA).  It also
   provides recommendations on the use of transport by AAA protocols.
   This includes usage of standards-track RFCs as well as experimental
   proposals.

1.1.  Requirements Language

   In this document, the key words "MAY", "MUST, "MUST NOT", "optional",
   "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as
   described in [RFC2119].

1.2.  Terminology

   Accounting