Internet DRAFT - draft-ietf-snmp-traps
draft-ietf-snmp-traps
Internet Draft Convention for Defining Traps Sep 90
A Convention for Defining Traps
for use with the SNMP
Tue Sep 25 17:01:28 1990
Marshall T. Rose
(editor)
Performance Systems International, Inc.
5201 Great America Parkway
Suite 3106
Santa Clara, CA 95054
US
mrose@psi.com
1. Status of this Memo
This memo describes a straight-forward approach towards
defining traps used with the SNMP. It is specifically
intended for use by the authors of experimental MIBs, and
emphasizes a concise descriptive approach. Use of this
approach is fully consistent with the Internet-standard
network management framework.
Distribution of this memo is unlimited. Please send comments
to: Marshall T. Rose <mrose@psi.com>.
M.T. Rose (editor) [Page 1]
Internet-Draft Convention for Defining Traps Sep 90
2. Historical Perspective
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), defined in RFC 1067, 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), and RFC 1066, which defined
the Management Information Base (MIB). Both of these
documents were designed so as to be 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 [2], 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,
based on the SNMP, to respond to new operational needs in the
Internet community by producing MIB-II.
In May of 1990, the core documents were elevated to "Standard
Protocols" with "Recommended" status. As such, the Internet-
standard network management framework consists of: Structure
and Identification of Management Information for TCP/IP-based
internets, RFC 1155 [3], which describes how managed objects
contained in the MIB are defined; Management Information Base
for Network Management of TCP/IP-based internets, which
describes the managed objects contained in the MIB, RFC 1156
[4]; and, the Simple Network Management Protocol, RFC 1157
[5], which defines the protocol used to manage these objects.
M.T. Rose (editor) [Page 2]
Internet-Draft Convention for Defining Traps Sep 90
3. Defining Traps
Due to its initial requirement to be protocol-independent, the
Internet-standard SMI does not provide a means for defining
traps. Instead, the SNMP defines a few standardized traps and
provides a means for management enterprises to transmit
enterprise-specific traps.
However, with the introduction of experimental MIBs, some of
which have a need to define experiment-specific traps, a
convenient means of defining traps is desirable. The TRAP-
TYPE macro is suggested for this purpose:
TRAP-TYPE MACRO ::=
BEGIN
TYPE NOTATION ::= "ENTERPRISE" enterprise
(VALUE OBJECT IDENTIFIER)
VarPart
DescrPart
ReferPart
VALUE NOTATION ::= value (VALUE INTEGER)
VarPart ::=
"VARIABLES" "{" VarTypes "}"
| empty
VarTypes ::=
VarType | VarTypes "," VarType
VarType ::=
vartype (VALUE ObjectName)
DescrPart ::=
"DESCRIPTION" description (VALUE DisplayString)
| empty
ReferPart ::=
"REFERENCE" reference (VALUE DisplayString)
| empty
END
M.T. Rose (editor) [Page 3]
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3.1. Mapping of the TRAP-TYPE macro
It should be noted that the expansion of the TRAP-TYPE macro
is something which conceptually happens during implementation
and not during run-time.
3.1.1. Mapping of the ENTERPRISE clause
The ENTERPRISE clause, which must be present, defines the
management enterprise under whose registration authority this
trap is defined (for a discussion on delegation of
registration authority, see the SMI [3]). This value is
placed inside the enterprise field of the SNMP Trap-PDU.
By convention, if the value of the ENTERPRISE clause is "snmp"
as defined in MIB-II, then instead of using this value, the
value of sysObjectID is placed in the enterprise field of the
SNMP Trap-PDU. This provides a simple means of using the
TRAP-TYPE macro to represent the existing standard SNMP traps;
it is not intended to provide a means to define additional
standard SNMP traps.
3.1.2. Mapping of the VARIABLES clause
The VARIABLES clause, which need not be present, defines the
ordered sequence of MIB objects which are contained within
every instance of the trap type. Each variable is placed, in
order, inside the variable-bindings field of the SNMP Trap-
PDU. Note that at the option of the agent, additional
variables may follow in the variable-bindings field.
3.1.3. Mapping of the DESCRIPTION clause
The DESCRIPTION clause, which need not be present, contains a
textual definition of the trap type. Note that in order to
conform to the ASN.1 syntax, the entire value of this clause
must be enclosed in double quotation marks, although the value
may be multi-line.
Further, note that if the MIB module does not contain a
textual description of the object type elsewhere then the
DESCRIPTION clause must be present.
M.T. Rose (editor) [Page 4]
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3.1.4. Mapping of the REFERENCE clause
The REFERENCE clause, which need not be present, contains a
textual cross-reference to a trap, event, or alarm, defined in
some other MIB module. This is useful when de-osifying a MIB
produced by some other organization.
3.1.5. Mapping of the TRAP-TYPE value
The value of an invocation of the TRAP-TYPE macro is the
(integer) number which is uniquely assigned to the trap by the
registration authority indicated by the ENTERPRISE clause.
This value is placed inside the specific-trap field of the
SNMP Trap-PDU, and the generic-trap field is set to
"enterpriseSpecific(6)".
By convention, if the value of the ENTERPRISE clause is "snmp"
as defined in MIB-II, then the value of an invocation of the
TRAP-TYPE macro is placed inside the generic-trap field of the
SNMP Trap-PDU, and the specific-trap field is set to 0. This
provides a simple means of using the TRAP-TYPE macro to
represent the existing standard SNMP traps; it is not intended
to provide a means to define additional standard SNMP traps.
M.T. Rose (editor) [Page 5]
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3.2. Usage Example
Consider a simple example of an enterprise-specific trap that
is sent when a communication link failure is encountered:
myEnterprise OBJECT IDENTIFIER ::= { enterprises 9999 }
myLinkDown TRAP-TYPE
ENTERPRISE myEnterprise
VARIABLES { ifIndex }
DESCRIPTION
"A myLinkDown trap signifies that the sending
SNMP application entity recognizes a failure
in one of the communications links represented
in the agent's configuration."
::= 2
M.T. Rose (editor) [Page 6]
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4. Acknowledgements
The editor acknowledges the comments of the following
individuals:
Jeffrey Case, UTK and SNMP Research
James Davin, MIT-LCS
Mark Fedor, PSI
Keith McCloghrie, HLS
Martin Schoffstall, PSI
Wengyik Yeong, PSI
M.T. Rose (editor) [Page 7]
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5. References
[1] V. Cerf, IAB Recommendations for the Development of
Internet Network Management Standards. Internet Working
Group Request for Comments 1052. Network Information
Center, SRI International, Menlo Park, California,
(April, 1988).
[2] V. Cerf, Report of the Second Ad Hoc Network Management
Review Group, Internet Working Group Request for Comments
1109. Network Information Center, SRI International,
Menlo Park, California, (August, 1989).
[3] M.T. Rose and K. McCloghrie, Structure and Identification
of Management Information for TCP/IP-based internets,
Internet Working Group Request for Comments 1155.
Network Information Center, SRI International, Menlo
Park, California, (May, 1990).
[4] K. McCloghrie and M.T. Rose, Management Information Base
for Network Management of TCP/IP-based internets,
Internet Working Group Request for Comments 1156.
Network Information Center, SRI International, Menlo
Park, California, (May, 1990).
[5] J.D. Case, M.S. Fedor, M.L. Schoffstall, and J.R. Davin,
Simple Network Management Protocol, Internet Working
Group Request for Comments 1157. Network Information
Center, SRI International, Menlo Park, California, (May,
1990).
[6] Information processing systems - Open Systems
Interconnection - Specification of Abstract Syntax
Notation One (ASN.1), International Organization for
Standardization. International Standard 8824, (December,
1987).
[7] M.T. Rose (editor), Management Information Base for
Network Management of TCP/IP-based internets: MIB-II,
Internet Working Group Request for Comments 1158.
Network Information Center, SRI International, Menlo
Park, California, (May, 1990).
M.T. Rose (editor) [Page 8]
Internet-Draft Convention for Defining Traps Sep 90
Table of Contents
1 Status of this Memo ................................... 1
2 Historical Perspective ................................ 2
3 Defining Traps ........................................ 3
3.1 Mapping of the TRAP-TYPE macro ...................... 4
3.1.1 Mapping of the ENTERPRISE clause .................. 4
3.1.2 Mapping of the VARIABLES clause ................... 4
3.1.3 Mapping of the DESCRIPTION clause ................. 4
3.1.4 Mapping of the REFERENCE clause ................... 5
3.1.5 Mapping of the TRAP-TYPE value .................... 5
3.2 Usage Example ....................................... 6
4 Acknowledgements ...................................... 7
5 References ............................................ 8
M.T. Rose (editor) [Page 9]
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