Simple Network Management Protocol (SNMP) Context EngineID Discovery
RFC 5343

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 03

Network Working Group                                   J. Schoenwaelder
Request for Comments: 5343                      Jacobs University Bremen
Updates: 3411                                             September 2008
Category: Standards Track

  Simple Network Management Protocol (SNMP) Context EngineID Discovery

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.

Abstract

   The Simple Network Management Protocol (SNMP) version three (SNMPv3)
   requires that an application know the identifier (snmpEngineID) of
   the remote SNMP protocol engine in order to retrieve or manipulate
   objects maintained on the remote SNMP entity.

   This document introduces a well-known localEngineID and a discovery
   mechanism that can be used to learn the snmpEngineID of a remote SNMP
   protocol engine.  The proposed mechanism is independent of the
   features provided by SNMP security models and may also be used by
   other protocol interfaces providing access to managed objects.

   This document updates RFC 3411.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . . . 2
   3.  Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     3.1.  Local EngineID  . . . . . . . . . . . . . . . . . . . . . . 4
     3.2.  EngineID Discovery  . . . . . . . . . . . . . . . . . . . . 4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 7

Schoenwaelder               Standards Track                     [Page 1]
RFC 5343            SNMP Context EngineID Discovery       September 2008

1.  Introduction

   To retrieve or manipulate management information using the third
   version of the Simple Network Management Protocol (SNMPv3) [RFC3410],
   it is necessary to know the identifier of the remote SNMP protocol
   engine, the so-called snmpEngineID [RFC3411].  While an appropriate
   snmpEngineID can in principle be configured on each management
   application for each SNMP agent, it is often desirable to discover
   the snmpEngineID automatically.

   This document introduces a discovery mechanism that can be used to
   learn the snmpEngineID of a remote SNMP protocol engine.  The
   proposed mechanism is independent of the features provided by SNMP
   security models.  The mechanism has been designed to coexist with
   discovery mechanisms that may exist in SNMP security models, such as
   the authoritative engine identifier discovery of the User-based
   Security Model (USM) of SNMP [RFC3414].

   This document updates RFC 3411 [RFC3411] by clarifying the IANA rules
   for the maintenance of the SnmpEngineID format registry.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  Background

   Within an administrative domain, an SNMP engine is uniquely
   identified by an snmpEngineID value [RFC3411].  An SNMP entity, which
   consists of an SNMP engine and several SNMP applications, may provide
   access to multiple contexts.

   An SNMP context is a collection of management information accessible
   by an SNMP entity.  An item of management information may exist in
   more than one context and an SNMP entity potentially has access to
   many contexts [RFC3411].  A context is identified by the snmpEngineID
   value of the entity hosting the management information (also called a
   contextEngineID) and a context name that identifies the specific
   context (also called a contextName).

   To identify an individual item of management information within an
   administrative domain, a four tuple is used consisting of

   1.  a contextEngineID,

   2.  a contextName,

Schoenwaelder               Standards Track                     [Page 2]
RFC 5343            SNMP Context EngineID Discovery       September 2008

   3.  an object type, and

   4.  its instance identification.

   The last two elements are encoded in an object identifier (OID)
   value.  The contextName is a character string (following the
   SnmpAdminString textual convention of the SNMP-FRAMEWORK-MIB
   [RFC3411]) while the contextEngineID is an octet string constructed