Network Working Group                                            J. Case
Request for Comments:  1157                                SNMP Research
Obsoletes:  RFC 1098                                            M. Fedor
                                       Performance Systems International
                                                          M. Schoffstall
                                       Performance Systems International
                                                                J. Davin
                                     MIT Laboratory for Computer Science
                                                                May 1990


              A Simple Network Management Protocol (SNMP)

                           Table of Contents

   1. Status of this Memo ...................................    2
   2. Introduction ..........................................    2
   3. The SNMP Architecture .................................    5
   3.1 Goals of the Architecture ............................    5
   3.2 Elements of the Architecture .........................    5
   3.2.1 Scope of Management Information ....................    6
   3.2.2 Representation of Management Information ...........    6
   3.2.3 Operations Supported on Management Information .....    7
   3.2.4 Form and Meaning of Protocol Exchanges .............    8
   3.2.5 Definition of Administrative Relationships .........    8
   3.2.6 Form and Meaning of References to Managed Objects ..   12
   3.2.6.1 Resolution of Ambiguous MIB References ...........   12
   3.2.6.2 Resolution of References across MIB Versions......   12
   3.2.6.3 Identification of Object Instances ...............   12
   3.2.6.3.1 ifTable Object Type Names ......................   13
   3.2.6.3.2 atTable Object Type Names ......................   13
   3.2.6.3.3 ipAddrTable Object Type Names ..................   14
   3.2.6.3.4 ipRoutingTable Object Type Names ...............   14
   3.2.6.3.5 tcpConnTable Object Type Names .................   14
   3.2.6.3.6 egpNeighTable Object Type Names ................   15
   4. Protocol Specification ................................   16
   4.1 Elements of Procedure ................................   17
   4.1.1 Common Constructs ..................................   19
   4.1.2 The GetRequest-PDU .................................   20
   4.1.3 The GetNextRequest-PDU .............................   21
   4.1.3.1 Example of Table Traversal .......................   23
   4.1.4 The GetResponse-PDU ................................   24
   4.1.5 The SetRequest-PDU .................................   25
   4.1.6 The Trap-PDU .......................................   27
   4.1.6.1 The coldStart Trap ...............................   28
   4.1.6.2 The warmStart Trap ...............................   28
   4.1.6.3 The linkDown Trap ................................   28
   4.1.6.4 The linkUp Trap ..................................   28



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RFC 1157                          SNMP                          May 1990


   4.1.6.5 The authenticationFailure Trap ...................   28
   4.1.6.6 The egpNeighborLoss Trap .........................   28
   4.1.6.7 The enterpriseSpecific Trap ......................   29
   5. Definitions ...........................................   30
   6. Acknowledgements ......................................   33
   7. References ............................................   34
   8. Security Considerations................................   35
   9. Authors' Addresses.....................................   35

1.  Status of this Memo

   This RFC is a re-release of RFC 1098, with a changed "Status of this
   Memo" section plus a few minor typographical corrections.  This memo
   defines a simple protocol by which management information for a
   network element may be inspected or altered by logically remote
   users.  In particular, together with its companion memos which
   describe the structure of management information along with the
   management information base, these documents provide a simple,
   workable architecture and system for managing TCP/IP-based internets
   and in particular the Internet.

   The Internet Activities Board recommends that all IP and TCP
   implementations be network manageable.  This implies implementation
   of the Internet MIB (RFC-1156) and at least one of the two
   recommended management protocols SNMP (RFC-1157) or CMOT (RFC-1095).
   It should be noted that, at this time, SNMP is a full Internet
   standard and CMOT is a draft standard.  See also the Host and Gateway
   Requirements RFCs for more specific information on the applicability
   of this standard.

   Please refer to the latest edition of the "IAB Official Protocol
   Standards" RFC for current information on the state and status of
   standard Internet protocols.

   Distribution of this memo is unlimited.

2.  Introduction

   As reported in RFC 1052, IAB Recommendations for the Development of
   Internet Network Management Standards [1], a two-prong strategy for
   network management of TCP/IP-based internets was undertaken.  In the
   short-term, the Simple Network Management Protocol (SNMP) was to be
   used to manage nodes in the Internet community.  In the long-term,
   the use of the OSI network management framework was to be examined.
   Two documents were produced to define the management information: RFC
   1065, which defined the Structure of Management Information (SMI)
   [2], and RFC 1066, which defined the Management Information Base
   (MIB) [3].  Both of these documents were designed so as to be



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   compatible with both the SNMP and the OSI network management
   framework.

   This strategy was quite successful in the short-term: Internet-based
   network management technology was fielded, by both the research and
   commercial communities, within a few months.  As a result of this,
   portions of the Internet community became network manageable in a
   timely fashion.

   As reported in RFC 1109, Report of the Second Ad Hoc Network
   Management Review Group [4], the requirements of the SNMP and the OSI
   network management frameworks were more different than anticipated.
   As such, the requirement for compatibility between the SMI/MIB and
   both frameworks was suspended.  This action permitted the operational
   network management framework, the SNMP, to respond to new operational
   needs in the Internet community by producing documents defining new
   MIB items.

   The IAB has designated the SNMP, SMI, and the initial Internet MIB to
   be full "Standard Protocols" with "Recommended" status.  By this
   action, the IAB recommends that all IP and TCP implementations be
   network manageable and that the implementations that are network
   manageable are expected to adopt and implement the SMI, MIB, and
   SNMP.

   As such, the current network management framework for TCP/IP- based
   internets consists of:  Structure and Identification of Management
   Information for TCP/IP-based Internets,