V2ToV1 Mapping SNMPv2 onto SNMPv1 within a bi-lingual SNMP agent
RFC 2089

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Network Working Group                                          B. Wijnen
Request for Comments: 2089                                           IBM
Category: Informational                                          D. Levi
                                                      SNMP Research, Inc
                                                            January 1997

                                 V2ToV1
                       Mapping SNMPv2 onto SNMPv1
                     within a bi-lingual SNMP agent

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   The goal of this memo is to document a common way of mapping an
   SNMPv2 response into an SNMPv1 response within a bi-lingual SNMP
   agent (one that supports both SNMPv1 and SNMPv2).

Table of Contents

     1.0  Introduction  . . . . . . . . . . . . . . . . . . . . . . .  2
     2.0  Mapping SNMPv2 into SNMPv1  . . . . . . . . . . . . . . . .  2
     2.1  Mapping SNMPv2 error-status into SNMPv1 error-status  . . .  3
     2.2  Mapping SNMPv2 exceptions into SNMPv1   . . . . . . . . . .  3
     2.3  Mapping noSuchObject and noSuchInstance   . . . . . . . . .  4
     2.4  Mapping endOfMibView  . . . . . . . . . . . . . . . . . . .  5
     2.5  Mapping SNMPv2 SMI into SNMPv1  . . . . . . . . . . . . . .  5
     3.0  Processing SNMPv1 requests  . . . . . . . . . . . . . . . .  6
     3.1  Processing an SNMPv1 GET request  . . . . . . . . . . . . .  6
     3.2  Processing an SNMPv1 GETNEXT request  . . . . . . . . . . .  7
     3.3  Processing an outgoing SNMPv2 trap  . . . . . . . . . . . .  8
     4.0  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . 10
     5.0  References  . . . . . . . . . . . . . . . . . . . . . . . . 10
     6.0  Security Considerations   . . . . . . . . . . . . . . . . . 10
     7.0  Authors' Addresses  . . . . . . . . . . . . . . . . . . . . 11
     Appendix A.  Background Information  . . . . . . . . . . . . .   12
     A.1  Mapping of error-status Values  . . . . . . . . . . . . .   12
     A.2  SNMPv1 traps without Counter64 varBinds.  . . . . . . . .   12

Wijnen & Levi                Informational                      [Page 1]
RFC 2089                         V2toV1                     January 1997

1.0  Introduction

   We now have the SNMPv1 protocol (RFC1157 [1]) as a full standard and
   the SNMPv2 protocol (RFC1905 [1]) as a DRAFT standard.  It can be
   expected that many agent implementations will support both SNMPv1 and
   SNMPv2 requests coming from SNMP management entities.  In many cases
   the underlying instrumentation will be implemented using the new
   SNMPv2 SMI and SNMPv2 protocol.  The SNMP engine then gets the task
   to ensure that any SNMPv2 response data coming from such SNMPv2
   compliant instrumentation gets converted to a proper SNMPv1 response
   if the original request came in as an SNMPv1 request.  The SNMP
   engine should also deal with mapping SNMPv2 traps which are generated
   by an application or by the SNMPv2 compliant instrumentation into
   SNMPv1 traps if the agent has been configured to send traps to an
   SNMPv1 manager.

   It seems beneficial if all such agents do this mapping in the same
   way. This document describes such a mapping based on discussions and
   perceived consensus on the various mailing lists.  The authors of
   this document have also compared their own implementations of these
   mappings. They had a few minor differences and decided to make their
   implementation behave the same and document this mapping so others
   can benefit from it.

   We recommend that all agents implement this same mapping.

   Note that the mapping described in this document should also be
   followed by SNMP proxies that provide a mapping between SNMPv1
   management applications and SNMPv2 agents.

2.0  Mapping SNMPv2 into SNMPv1

   These are the type of mappings that we need:

     o   Mapping of the SNMPv2 error-status into SNMPv1 error-status

     o   Mapping of the SNMPv2 exceptions into SNMPv1 error-status

     o   Skipping object instances that have a non-SNMPv1 Syntax
         (specifically Counter64)

     o   Mapping of SNMPv2 traps into SNMPv1 traps

Wijnen & Levi                Informational                      [Page 2]
RFC 2089                         V2toV1                     January 1997

2.1  Mapping SNMPv2 error-status into SNMPv1 error-status

   With the new SNMPv2 protocol (RFC1905 [1]) we get a set of error-
   status values that return the cause of an error in much more detail.
   But an SNMPv1 manager does not understand such error-status values.

   So, when the instrumentation code returns response data and uses an
   SNMPv2 error-status to report on the success or failure of the
   requested operation and if the original SNMP request is an SNMPv1
   request, then we must map such an error-status into an SNMPv1 error-