Transport Subsystem for the Simple Network Management Protocol (SNMP)
RFC 5590

Network Working Group                                      D. Harrington
Request for Comments: 5590                     Huawei Technologies (USA)
Updates: 3411, 3412, 3414, 3417                         J. Schoenwaelder
Category: Standards Track                       Jacobs University Bremen
                                                               June 2009

 Transport Subsystem for the Simple Network Management Protocol (SNMP)

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.

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Abstract

   This document defines a Transport Subsystem, extending the Simple
   Network Management Protocol (SNMP) architecture defined in RFC 3411.
   This document defines a subsystem to contain Transport Models that is
   comparable to other subsystems in the RFC 3411 architecture.  As work
   is being done to expand the transports to include secure transports,
   such as the Secure Shell (SSH) Protocol and Transport Layer Security

Harrington & Schoenwaelder  Standards Track                     [Page 1]
RFC 5590                SNMP Transport Subsystem               June 2009

   (TLS), using a subsystem will enable consistent design and modularity
   of such Transport Models.  This document identifies and describes
   some key aspects that need to be considered for any Transport Model
   for SNMP.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  The Internet-Standard Management Framework . . . . . . . .  3
     1.2.  Conventions  . . . . . . . . . . . . . . . . . . . . . . .  3
     1.3.  Where This Extension Fits  . . . . . . . . . . . . . . . .  4
   2.  Motivation . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Requirements of a Transport Model  . . . . . . . . . . . . . .  7
     3.1.  Message Security Requirements  . . . . . . . . . . . . . .  7
       3.1.1.  Security Protocol Requirements . . . . . . . . . . . .  7
     3.2.  SNMP Requirements  . . . . . . . . . . . . . . . . . . . .  8
       3.2.1.  Architectural Modularity Requirements  . . . . . . . .  8
       3.2.2.  Access Control Requirements  . . . . . . . . . . . . . 11
       3.2.3.  Security Parameter Passing Requirements  . . . . . . . 12
       3.2.4.  Separation of Authentication and Authorization . . . . 12
     3.3.  Session Requirements . . . . . . . . . . . . . . . . . . . 13
       3.3.1.  No SNMP Sessions . . . . . . . . . . . . . . . . . . . 13
       3.3.2.  Session Establishment Requirements . . . . . . . . . . 14
       3.3.3.  Session Maintenance Requirements . . . . . . . . . . . 15
       3.3.4.  Message Security versus Session Security . . . . . . . 15
   4.  Scenario Diagrams and the Transport Subsystem  . . . . . . . . 16
   5.  Cached Information and References  . . . . . . . . . . . . . . 17
     5.1.  securityStateReference . . . . . . . . . . . . . . . . . . 17
     5.2.  tmStateReference . . . . . . . . . . . . . . . . . . . . . 17
       5.2.1.  Transport Information  . . . . . . . . . . . . . . . . 18
       5.2.2.  securityName . . . . . . . . . . . . . . . . . . . . . 19
       5.2.3.  securityLevel  . . . . . . . . . . . . . . . . . . . . 20
       5.2.4.  Session Information  . . . . . . . . . . . . . . . . . 20
   6.  Abstract Service Interfaces  . . . . . . . . . . . . . . . . . 21
     6.1.  sendMessage ASI  . . . . . . . . . . . . . . . . . . . . . 21