path: root/doc/rfc/rfc5675.txt

Network Working Group                                         V. Marinov
Request for Comments: 5675                              J. Schoenwaelder
Category: Standards Track                       Jacobs University Bremen
                                                            October 2009


           Mapping Simple Network Management Protocol (SNMP)
                    Notifications to SYSLOG Messages

Abstract

   This memo defines a mapping from Simple Network Management Protocol
   (SNMP) notifications to SYSLOG messages.

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) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the BSD License.















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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
     1.1.  Conventions  . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Background . . . . . . . . . . . . . . . . . . . . . . . . . .  3
     2.1.  SNMP Notifications . . . . . . . . . . . . . . . . . . . .  3
     2.2.  SYSLOG Notifications . . . . . . . . . . . . . . . . . . .  5
   3.  Mapping SNMP Notifications to SYSLOG Messages  . . . . . . . .  5
     3.1.  SYSLOG Header  . . . . . . . . . . . . . . . . . . . . . .  6
     3.2.  Structured Data  . . . . . . . . . . . . . . . . . . . . .  7
     3.3.  MSG Data . . . . . . . . . . . . . . . . . . . . . . . . .  9
   4.  Relationship to the SYSLOG-MSG-MIB . . . . . . . . . . . . . . 10
   5.  Usage Example  . . . . . . . . . . . . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   8.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 13
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 13
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 14

1.  Introduction

   SNMP and SYSLOG are two widely used protocols to communicate event
   notifications.  Although co-existence of several management protocols
   in one operational environment is possible, certain environments
   require that all event notifications be collected by a single system
   daemon, such as a SYSLOG collector or an SNMP notification receiver,
   via a single management protocol.  In such environments, it is
   necessary to translate event notifications between management
   protocols.

   The latest version of SYSLOG, specified in [RFC5424], supports a
   structured data element format.  Structured data elements allow us to
   map between SNMP notifications and SYSLOG messages without losing
   information.  In this memo, we specify a concrete mapping from SNMP
   event notifications [RFC3416] into SYSLOG messages [RFC5424].  We
   specify how the SYSLOG message format should be utilized to carry the
   information contained in an SNMP notification message.  A new SYSLOG
   structured data element is defined, which carries the PDU portion of
   an SNMP notification message.

1.1.  Conventions

   A system that has the capability of receiving SNMP notification
   messages from an SNMP notification originator and sending the SNMP
   data contained inside in a SYSLOG message format to a SYSLOG
   collector is referred to in this memo as an "SNMP-to-SYSLOG
   translator".  By definition, such a system should have an SNMP



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   notification receiver application and a SYSLOG originator running in
   order to be able to perform the functions of an "SNMP-to-SYSLOG
   translator".

   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 [RFC2119].

2.  Background

2.1.  SNMP Notifications

   A detailed introduction to the SNMP Management Framework can be found
   in [RFC3410].  The SNMP Management Architecture is described in
   [RFC3411].  Managed objects are accessed via a virtual information
   store, termed the Management Information Base or MIB [RFC3418].
   Objects in the MIB are defined using the mechanisms defined in the
   Structure of Management Information (SMI) [RFC2578].

   An SNMP notification message is generated and transmitted by an SNMP
   entity on behalf of a notification originator application [RFC3413].
   SNMP notifications are often used to notify a notification receiver
   application at a logically remote SNMP entity that an event has
   occurred or that a certain condition is present.  There are two types
   of SNMP protocol operations that are associated with SNMP
   notification messages [RFC3416]:

   o  SNMPv2-Trap-PDU, an unconfirmed notification delivery mechanism

   o  InformRequest-PDU, a confirmed notification delivery mechanism

   The scopedPDU portion of an SNMPv3 trap or inform message has the
   following format [RFC3412]:

          ScopedPDU ::= SEQUENCE {
              contextEngineID  OCTET STRING,
              contextName      OCTET STRING,
              data             ANY -- e.g., PDUs as defined in [RFC3416]
          }

   The data member of the SEQUENCE ScopedPDU carries an SNMPv2-Trap-PDU
   or an InformRequest-PDU.  They both have the same structure:









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        PDUs ::= [7] IMPLICIT SEQUENCE {
            request-id           INTEGER,
            error-status         INTEGER,    -- ignored in notifications
            error-index          INTEGER,    -- ignored in notifications
            variable-bindings    VarBindList
        }

        -- variable binding

        VarBind ::= SEQUENCE {
            name ObjectName,

            CHOICE {
                value          ObjectSyntax,
                unSpecified    NULL,    -- in retrieval requests
                                        -- exceptions in responses
                noSuchObject   [0] IMPLICIT NULL,
                noSuchInstance [1] IMPLICIT NULL,
                endOfMibView   [2] IMPLICIT NULL
            }
        }

        -- variable-binding list

        VarBindList ::= SEQUENCE (SIZE (0..max-bindings)) OF VarBind

   The first two variable bindings in the variable binding list of an
   SNMPv2-Trap-PDU or InformRequest-PDU are sysUpTime.0 [RFC3418] and
   snmpTrapOID.0 [RFC3418], respectively.  If the OBJECTS clause is
   present in the invocation of the corresponding NOTIFICATION-TYPE
   macro, then each corresponding variable, as instantiated by this
   notification, is copied, in order, to the variable-bindings field.
   If any additional variables are being included (at the option of the
   generating SNMP entity), then each is copied to the variable-bindings
   field.

   In the case of SNMPv1 or SNMPv2c notifications, the contextEngineID
   and the contextName parameters are not present in notification
   messages.

   This document assumes that notifications are in the format defined in
   [RFC3416].  Notifications in the SNMPv1 notification format MUST be
   translated as described in Section 3.1 of [RFC3584].








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2.2.  SYSLOG Notifications

   The SYSLOG protocol is defined in [RFC5424].  The message contains a
   global header and a number of structured data elements.  The ABNF
   [RFC5234] representation of a SYSLOG message is defined in RFC 5424
   [RFC5424].  The relevant productions for structured data elements
   are:

         STRUCTURED-DATA = NILVALUE / 1*SD-ELEMENT
         SD-ELEMENT      = "[" SD-ID *(SP SD-PARAM) "]"
         SD-PARAM        = PARAM-NAME "=" %d34 PARAM-VALUE %d34
         SD-ID           = SD-NAME
         PARAM-NAME      = SD-NAME
         PARAM-VALUE     = UTF-8-STRING ; characters '"', '\' and
                                        ; ']' MUST be escaped.
         SD-NAME         = 1*32PRINTUSASCII
                           ; except '=', SP, ']', %d34 (")

         UTF-8-STRING    = *OCTET ; Any VALID UTF-8 String
                           ; "shortest form" MUST be used

         OCTET           = %d00-255
         SP              = %d32
         PRINTUSASCII    = %d33-126
         NILVALUE        = "-"

3.  Mapping SNMP Notifications to SYSLOG Messages

   In this section, we define how the scopedPDU portion from an SNMP
   notification message is used to generate a message in the SYSLOG
   format.  The notification receiver application at the SNMP-to-SYSLOG
   translator is listening for incoming notifications.  After a
   notification is received by the SNMP engine, the data portion is
   forwarded to the notification receiver application.  The data portion
   contains the scopedPDU of the message, which is used by the SYSLOG
   originator on the SNMP-to-SYSLOG translator to generate a SYSLOG
   message and send it to a SYSLOG collector (or proxy).  Note that
   every SNMP notification maps to exactly one SYSLOG message.













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   +------------+              +------------------+
   |snmp        |     snmp     |                  | syslog  +---------+
   |notification| notification |  +------------+  | message |syslog   |
   |originator  |------------->|  |syslog      |  |-------->|collector|
   +------------+              |  |originator  |  |         +---------+
   +------------+              |  +------------+  |
   |snmp        |     snmp     |  +------------+  | syslog  +---------+
   |notification| notification |  |snmp        |  | message |syslog   |
   |originator  |------------->|  |notification|  |-------->|collector|
   +------------+              |  |receiver    |  |         +---------+
   +------------+              |  +------------+  |
   |snmp        |     snmp     |                  |
   |notification| notification |  SNMP-to-SYSLOG  |
   |originator  |------------->|    translator    |
   +------------+              +------------------+

              Figure 1: SNMP-to-SYSLOG Translator Deployment

   A common deployment scenario is shown in Figure 1.  There can be many
   SNMP notification originators that send SNMP event notifications to
   an SNMP-to-SYSLOG translator.  The SNMP-to-SYSLOG translator extracts
   the data portion of the notification, generates a SYSLOG message, and
   sends the SYSLOG message to a SYSLOG collector, which is responsible
   for collecting and storing all notification messages.  The arrows in
   Figure 1 indicate message flows, not individual messages.

   The SNMP-to-SYSLOG translator is not transparent for a SYSLOG
   collector.  The global header of the SYSLOG message generated by the
   SNMP-to-SYSLOG translator is filled with parameters that are specific
   for the system running the SNMP-to-SYSLOG translator, such as its
   hostname, timestamp, etc.  The data portion (scopedPDU for SNMPv3 or
   PDU for SNMPv1/SNMPv2c) of the SNMP notification message is contained
   in the structured data of the SYSLOG message.

   Implementations MUST drop invalid SNMP messages before they are
   passed to the SNMP-to-SYSLOG translator.

3.1.  SYSLOG Header

   The SNMP-to-SYSLOG translator fills the HEADER field of a SYSLOG
   message with parameters specific to the system on which it is
   running.  The default facility level for SYSLOG messages containing
   SNMP notifications SHOULD be 3, which corresponds to messages
   generated by system daemons.  The default severity level SHOULD be 5,
   which corresponds to "Notice: normal but significant condition".  If
   the SNMP-to-SYSLOG translator has a notion of the type of
   notification that has been received, it might choose other values for
   facility and severity level.



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   The VERSION, TIMESTAMP, HOSTNAME, APP-NAME, PROCID, and MSGID fields
   in the SYSLOG message header are filled with values that are specific
   to the system on which the SNMP-to-SYSLOG translator is running.  The
   character set used in the HEADER MUST be seven-bit ASCII in an eight-
   bit field, as described in [RFC5424].

3.2.  Structured Data

   The STRUCTURED-DATA field of a SYSLOG message carries the ScopedPDU
   (or PDU) portion of an SNMP notification message.  For the purpose of
   carrying SNMP notification data, a new SD-ID element is defined.  The
   ABNF [RFC5234] representation of the new structured element is:

   SNMP-SD-ELEMENT = "[" SNMP-SD-ID [CTX] *VARBIND "]"
   SNMP-SD-ID      = %x73.6E.6D.70         ; snmp
   CTX             = CTXENGINE CTXNAME
   CTXENGINE       = SP "ctxEngine=" %d34 HEXSTRING %d34
   CTXNAME         = SP "ctxName=" %d34 PARAM-VALUE %d34
   VARBIND         = SP VARNAME [SP VARLABEL] SP VARVALUE [SP VALSTRING]
   VARNAME         = %d118 NUM "=" %d34 OID %d34         ; "vN="
   VARLABEL        = %d108 NUM "=" %d34 PARAM-VALUE %d34 ; "lN="
   VARVALUE        = VALOID / VALHEXSTRING / VALCOUNTER32 / VALCOUNTER64
                     / VALUNSIGNED32 / VALINTEGER32 / VALIP / VALNULL
                     / VALOPAQUE / VALTIMETICKS / VALSTRING

   VALOID          = %d111 NUM "=" %d34 OID %d34         ; "oN="
   VALHEXSTRING    = %d120 NUM "=" %d34 HEXSTRING %d34   ; "xN="
   VALCOUNTER32    = %d99  NUM "=" %d34 UNSIGNED32 %d34  ; "cN="
   VALCOUNTER64    = %d67  NUM "=" %d34 UNSIGNED64 %d34  ; "CN="
   VALUNSIGNED32   = %d117 NUM "=" %d34 UNSIGNED32 %d34  ; "uN="
   VALINTEGER32    = %d100 NUM "=" %d34 INTEGER32 %d34   ; "dN="
   VALIP           = %d105 NUM "=" %d34 IPV4ADDRESS %d34 ; "iN="
   VALNULL         = %d110 NUM "=" %d34 %d34             ; "nN="
   VALOPAQUE       = %d112 NUM "=" %d34 HEXSTRING %d34   ; "pN="
   VALTIMETICKS    = %d116 NUM "=" %d34 UNSIGNED32 %d34  ; "tN="
   VALSTRING       = %d97  NUM "=" %d34 PARAM-VALUE %d34 ; "aN="

   NUM             = NONZERODIGIT 0*DIGIT

   OID             = OIDSTART *("." OIDSUBID)
   OIDSTART        = (("0." / "1.") [%d49-51] DIGIT) / ("2." OIDSUBID)
   OIDSUBID        = ZERO / (NONZERODIGIT *DIGIT)

   PARAM-VALUE     = UTF-8-STRING ; characters '"', '\' and
                                  ; ']' MUST be escaped.
   UTF-8-STRING    = *OCTET ; Any VALID UTF-8 String
                            ; "shortest form" MUST be used
   HEXSTRING       = *HEX



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   INTEGER32       = ["-"] NONZERODIGIT 0*DIGIT
   UNSIGNED32      = NONZERODIGIT 0*DIGIT
   UNSIGNED64      = NONZERODIGIT 0*DIGIT
   IPV4ADDRESS     = d8 "." d8 "." d8 "." d8

   d8              = DIGIT               ; 0-9
                     / %d49-57 DIGIT       ; 10-99
                     / "1" 2DIGIT          ; 100-199
                     / "2" %d48-52 DIGIT   ; 200-249
                     / "25" %d48-53        ; 250-255

   HEX             = DIGIT / %x41-46 / %x61-66       ; 0-9 / A-F / a-f
   NONZERODIGIT    = %d49-57
   ZERO            = %d48
   DIGIT           = ZERO / NONZERODIGIT
   SP              = %d32

   Each SNMP-SD-ELEMENT starts with the SD-ID "snmp".  The first two
   SD-ID parameters are "ctxEngine" and "ctxName".  The context MUST be
   present in an SNMPv3 notification and therefore "ctxEngine" and
   "ctxName" MUST be present in a SYSLOG message generated by an SNMP-
   to-SYSLOG translator from an SNMPv3 notification.  The
   contextEngineID is encoded as an hexadecimal string while the
   contextName is encoded as a UTF8 string.

   The remaining parameters in the "snmp" SD-ID correspond to the
   varbind list elements contained in the SNMP PDU.  The name of a
   varbind is encoded as an OID in dotted notation.  The rendered OID is
   carried in a "vN" parameter, where N identifies the position of the
   varbind in the varbind list of the SNMP message (the first varbind
   having the position 1).  A MIB-aware implementation may in addition
   generate a parameter "lN" carrying the descriptor of the associated
   MIB object plus the instance identifier suffix (also called an OID
   label).  The number N again identifies the position of the varbind in
   the varbind list of the SNMP message.

   The value of a varbind is encoded depending on its type according to
   the rules shown in Table 1, and type-specific parameter names are
   used to convey the type information.  The number N again identifies
   the position of the varbind in the varbind list of the SNMP message.
   A MIB-aware implementation may in addition generate a parameter "aN"
   carrying an alternate textual representation of the value, which is
   obtained by applying DISPLAY-HINTs and translating named numbers into
   corresponding labels or OBJECT IDENTIFIER values to descriptors.  For
   SNMP object types that have a DISPLAY-HINT of the form 'Ma' or 'Mt',
   where M is some number, a MIB-aware implementation can choose to
   include the "aN" parameter and to suppress the corresponding "xN"
   parameter.  This special case saves space for textual objects.  A



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   receiver receiving an "aN" parameter without a matching value at
   position N can unambiguously convert the value carried in the "aN"
   parameter back to an OCTET STRING value.

   While the inclusion of additional parameters carrying OID labels or
   alternate value representations increases human readability, this
   comes at the cost of increased message size, which may cause
   truncation of SYSLOG messages.  Therefore, implementations SHOULD
   provide a configuration mechanism to enable/disable the generation of
   parameters carrying OID labels or alternate value representations.

      +--------------------+------------+--------------------------+
      | SNMP Type          | PARAM-NAME | Value Encoding           |
      +--------------------+------------+--------------------------+
      | OBJECT IDENTIFIER  |     oN     | dotted-decimal notation  |
      | OCTET STRING       |     xN     | hexadecimal string       |
      | Counter32          |     cN     | unsigned decimal number  |
      | Counter64          |     CN     | unsigned decimal number  |
      | Unsigned32         |     uN     | unsigned decimal number  |
      | INTEGER, Integer32 |     dN     | signed decimal number    |
      | IpAddress          |     iN     | dotted quad notation     |
      | Opaque             |     pN     | hexadecimal (BER) string |
      | TimeTicks          |     tN     | unsigned decimal number  |
      | NULL               |     nN     | zero-length string       |
      +--------------------+------------+--------------------------+

                Table 1: Mapping of SNMP Types to SD Params

   The SYSLOG message generated by the SNMP-to-SYSLOG translator may, in
   addition to the SNMP-SD-ELEMENT, include other structured data
   elements in its structured data part.  These additional structured
   data elements MUST comply with the specification in [RFC5424].

   In particular, the parameters in the "origin" SD-ID SHOULD identify
   the originator of the SNMP notification.  A suitable value for the
   "ip" parameter MAY be taken from the snmpTrapAddress varbind if
   present, and a suitable value for the "enterpriseId" parameter MAY be
   extracted from the snmpTrapOID varbind.

3.3.  MSG Data

   The MSG part of the SYSLOG message is optional and may contain a
   free-form message that provides a textual description of the SNMP
   event notification.  According to [RFC5424], the character set used
   in MSG SHOULD be Unicode, encoded using UTF-8 as specified in
   [RFC3629].  If the originator cannot encode the MSG in Unicode, it





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   MAY use any other encoding.  The originator MAY use the "language"
   parameters defined in [RFC5424] to convey information about the
   natural language used inside MSG.

4.  Relationship to the SYSLOG-MSG-MIB

   A companion document [RFC5676] defines an SNMP MIB module to
   represent SYSLOG messages and to send SYSLOG messages as SNMP
   notifications to SNMP notification receivers.  This section discusses
   the possibilities of using both specifications in combination.

   A SYSLOG collector implementing the SYSLOG-MSG-MIB module and the
   mapping of SNMP notifications to SYSLOG messages may be configured to
   translate received SYSLOG messages containing SNMP notifications back
   into the original SNMP notification.  In this case, the relevant
   tables of the SYSLOG-MSG-MIB will not be populated for SYSLOG
   messages carrying SNMP notifications.  This configuration allows
   operators to build a forwarding chain where SNMP notifications are
   "tunneled" through SYSLOG messages.  Due to size restrictions of the
   SYSLOG transports and the more verbose textual encoding used by
   SYSLOG, there is a possibility that SNMP notification content will
   get truncated when tunneled through SYSLOG, and thus the resulting
   SNMP notification may be incomplete.

   An SNMP management application supporting the SYSLOG-MSG-MIB and the
   mapping of SNMP notifications to SYSLOG messages may process
   information from the SYSLOG-MSG-MIB in order to emit a SYSLOG message
   representing the SYSLOG message recorded in the SYSLOG-MSG-MIB
   module.  This configuration allows operators to build a forwarding
   chain where SYSLOG messages are "tunneled" through SNMP messages.  A
   notification receiver can determine whether a syslogMsgNotification
   contained all structured data element parameters of a SYSLOG message.
   In case parameters are missing, a forwarding application MUST
   retrieve the missing parameters from the SYSLOG-MSG-MIB.  Regular
   polling of the SYSLOG-MSG-MIB can be used to take care of any lost
   SNMP notifications.

5.  Usage Example

   Here we provide an example of how an SNMP linkUp trap message is
   mapped into a SYSLOG message by using the mappings defined in
   Section 3.1 and Section 3.2.

   The linkUp notification is defined in [RFC2863] as follows:

   linkUp NOTIFICATION-TYPE
       OBJECTS { ifIndex, ifAdminStatus, ifOperStatus }
       STATUS  current



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       DESCRIPTION
          "A linkUp trap signifies that the SNMP entity, acting in an
          agent role, has detected that the ifOperStatus object for
          one of its communication links left the down state and
          transitioned into some other state (but not into the
          notPresent state).  This other state is indicated by the
          included value of ifOperStatus."
       ::= { snmpTraps 4 }

   The scopedPDU portion of an SNMP linkUp trap sent using the SNMPv3
   message format is shown below (the left column shows the Basic
   Encoding Rules (BER) encoding, while the right column indicates the
   corresponding ASN.1 definitions):

   30:7C                                         SEQUENCE {
      04:08:80:00:02:B8:04:61:62:63                800002b804616263
      04:04:63:74:78:31                            "ctx1"
      A7:6A                                        SNMPv2-Trap-PDU {
         02:03:6D:08:67                              INTEGER 7145575
         02:01:00                                    INTEGER 0
         02:01:00                                    INTEGER 0
         30:5D                                       SEQUENCE OF {
            30:0F                                      SEQUENCE {
               06:08:2B:06:01:02:01:01:03:00             sysUpTime.0
               43:03:01:72:8C                            94860 }
            30:17                                      SEQUENCE {
               06:0A:2B:06:01:06:03:01:01:04:01:00       snmpTrapOID.0
               06:09:2B:06:01:06:03:01:01:05:04          linkUp }
            30:0F                                      SEQUENCE {
               06:0A:2B:06:01:02:01:02:02:01:01:03       ifIndex.3
               02:01:03                                  3 }
            30:0F                                      SEQUENCE {
               06:0A:2B:06:01:02:01:02:02:01:07:03       ifAdminStatus.3
               02:01:01                                  up(1) }
            30:0F                                      SEQUENCE {
               06:0A:2B:06:01:02:01:02:02:01:08:03       ifOperStatus.3
               02:01:01                                  up(1) } } } }

   The corresponding SYSLOG message generated by the SNMP-to-SYSLOG
   translator is shown below.  (SYSLOG examples should be considered to
   be on one line.  They are wrapped on multiple lines in this document
   for readability purposes only.)

   <29>1 2003-10-11T22:14:15.003Z mymachine.example.com snmptrapd - ID47
     [snmp ctxEngine="800002b804616263" ctxName="ctx1"
       v1="1.3.6.1.2.1.1.3.0" l1="sysUpTime.0" d1="94860"
       v2="1.3.6.1.6.3.1.1.4.1.0" l2="snmpTrapOID.0"
         o2="1.3.6.1.6.3.1.1.5.4" a2="linkUp"



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       v3="1.3.6.1.2.1.2.2.1.1.3" d3="3"
       v4="1.3.6.1.2.1.2.2.1.7.3" d4="1" a4="up"
       v5="1.3.6.1.2.1.2.2.1.8.3" d5="1" a5="up"]

   The corresponding SYSLOG message has a priority value of 29, which
   means a facility level of 3 (system daemons) and a severity level of
   5 (Notice: normal but significant condition) according to the
   algorithm for calculation of priority value specified in Section
   6.2.1 of [RFC5424].  The rest of the fields in the header of the
   SYSLOG message are parameters that are specific to the system running
   the SNMP-to-SYSLOG translator.  The SYSLOG version is 1 and the
   message was generated at 22:14:15.003Z on 2003-10-11T by the host
   "mymachine.example.com".  The application on the SNMP-to-SYSLOG
   translator that generated the message was "snmptrapd"; there is no
   information about the process id, and the message on the SNMP-to-
   SYSLOG system is identified with the MSGID of ID47.

   The SYSLOG message contains one structured data element with an SD-ID
   of "snmp", which means that this is the scopedPDU portion of an SNMP
   event notification message.  The data that is contained in the
   notification is associated with the ContextEngineID "123456" and
   ContextName "ctx1".  The request-id of the SNMP notification message
   was "7145575".  Then follows the data portion of the scopedPDU.  The
   first two variables contained in the data portion are always the
   sysUpTime.0 and snmpTrapOID.0.  An snmpTrapOID.0 with a value of
   "1.3.6.1.6.3.1.1.5.4" means that this is a linkUp trap.  The
   parameters v3="1.3.6.1.2.1.2.2.1.1.3" d3="3" mean that the SNMP
   notification message is carrying the ifIndex object, which has a type
   INTEGER and a value of 3.  The parameters v4="1.3.6.1.2.1.2.2.1.7.3"
   d4="1" mean that the SNMP notification message is carrying the object
   ifAdminStatus, which has a type INTEGER and a value of 1.  The
   parameters v5="1.3.6.1.2.1.2.2.1.8.3" d5="1" mean that the SNMP
   notification message is carrying the object ifOperStatus, which has a
   type INTEGER and a value of "1".

6.  IANA Considerations

   IANA registered the SD-ID value "snmp" together with the PARAM-NAME
   values specified in Section 3.2 in the registry for SYSLOG Structured
   Data ID Values according to Section 9 in [RFC5424].  The notation <N>
   indicates a position number.

           SD-ID           PARAM-NAME
           snmp                            OPTIONAL
                           ctxEngine       OPTIONAL
                           ctxName         OPTIONAL
                           v<N>            OPTIONAL
                           l<N>            OPTIONAL



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                           o<N>            OPTIONAL
                           x<N>            OPTIONAL
                           c<N>            OPTIONAL
                           C<N>            OPTIONAL
                           u<N>            OPTIONAL
                           d<N>            OPTIONAL
                           i<N>            OPTIONAL
                           n<N>            OPTIONAL
                           p<N>            OPTIONAL
                           t<N>            OPTIONAL
                           a<N>            OPTIONAL

7.  Security Considerations

   The security considerations discussed in [RFC5424] apply to this
   document.

   The SNMP architecture supports an access control mechanism, ensuring
   that SNMP notifications are only sent to receivers who are authorized
   to receive the notification.  Network operators using this mapping of
   SNMP notifications to SYSLOG messages should enforce a consistent
   policy, preventing people from accessing SNMP notifications via the
   SYSLOG mapping that would otherwise not be accessible.

8.  Acknowledgments

   The editors wish to thank the following individuals for providing
   helpful comments on various versions of this document: Martin
   Bjorklund, Washam Fan, Rainer Gerhards, Tom Petch, and Dan Romascanu.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3411]  Harrington, D., Presuhn, R., and B. Wijnen, "An
              Architecture for Describing Simple Network Management
              Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
              December 2002.

   [RFC3412]  Case, J., Harrington, D., Presuhn, R., and B. Wijnen,
              "Message Processing and Dispatching for the Simple Network
              Management Protocol (SNMP)", STD 62, RFC 3412,
              December 2002.





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   [RFC3413]  Levi, D., Meyer, P., and B. Stewart, "Simple Network
              Management Protocol (SNMP) Applications", STD 62,
              RFC 3413, December 2002.

   [RFC3416]  Presuhn, R., "Version 2 of the Protocol Operations for the
              Simple Network Management Protocol (SNMP)", STD 62,
              RFC 3416, December 2002.

   [RFC3418]  Presuhn, R., "Management Information Base (MIB) for the
              Simple Network Management Protocol (SNMP)", STD 62,
              RFC 3418, December 2002.

   [RFC3584]  Frye, R., Levi, D., Routhier, S., and B. Wijnen,
              "Coexistence between Version 1, Version 2, and Version 3
              of the Internet-standard Network Management Framework",
              BCP 74, RFC 3584, August 2003.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, November 2003.

   [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 5234, January 2008.

   [RFC5424]  Gerhards, R., "The Syslog Protocol", RFC 5424, March 2009.

   [RFC5676]  Schoenwaelder, J., Clemm, A., and A. Karmakar,
              "Definitions of Managed Objects for Mapping SYSLOG
              Messages to Simple Network Management Protocol (SNMP)
              Notifications", RFC 5676, October 2009.

9.2.  Informative References

   [RFC2578]  McCloghrie, K., Perkins, D., and J. Schoenwaelder,
              "Structure of Management Information Version 2 (SMIv2)",
              RFC 2578, STD 58, April 1999.

   [RFC2863]  McCloghrie, K. and F. Kastenholz, "The Interfaces Group
              MIB", RFC 2863, June 2000.

   [RFC3410]  Case, J., Mundy, R., Partain, D., and B. Stewart,
              "Introduction and Applicability Statements for Internet-
              Standard Management Framework", RFC 3410, December 2002.









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Authors' Addresses

   Vladislav Marinov
   Jacobs University Bremen
   Campus Ring 1
   28725 Bremen
   Germany

   EMail: v.marinov@jacobs-university.de


   Juergen Schoenwaelder
   Jacobs University Bremen
   Campus Ring 1
   28725 Bremen
   Germany

   EMail: j.schoenwaelder@jacobs-university.de

































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