RFC3705

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Network Working Group B. Ray Request for Comments: 3705 PESA Switching Systems Category: Standards Track R. Abbi

                                                             Alcatel
                                                       February 2004
    High Capacity Textual Conventions for MIB Modules Using
        Performance History Based on 15 Minute Intervals

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) The Internet Society (2004). All Rights Reserved.

Abstract

This document presents a set of High Capacity Textual Conventions for use in MIB modules which require performance history based upon 15 minute intervals. The Textual Conventions defined in this document extend the conventions presented in RFC 3593 to 64 bit resolution using the conventions presented in RFC 2856.

The Internet-Standard Management Framework

For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of RFC 3410 RFC3410.

Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in STD 58, RFC 2578 RFC2578, STD 58, RFC 2579 RFC2579 and STD 58, RFC 2580 RFC2580.

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.

Overview

In cases where a manager must obtain performance history data about the behavior of equipment it manages, several strategies can be followed in the design of a MIB module that represents the managed equipment, including:

- The agent counts events on a continuous basis and, whenever

  desired, the manager obtains the value of the event counter and
  adjusts its understanding of the history of events at the agent.

- The agent allocates events to 'buckets' where each bucket

  represents an interval of time.

Telecommunications equipment often makes use of the latter strategy. For such equipment the standard practice is that history data is maintained by the agent in terms of 15-minute intervals [T1.231].

MIB modules for collecting performance history based on 15-minute intervals have been defined for the DS1/E1 RFC2495, DS3/E3 RFC2496, SONET/SDH RFC3592, ADSL RFC2662, HDLS2 and SHDSL RFC3276 interface types. These MIB modules use a common set of textual conventions defined in RFC3593.

A need has arisen to define 64-bit versions of the textual conventions in RFC3593. Ideally, these high-capacity textual conventions would be based on a Gauge64 or Unsigned64 data type, but unfortunately no such types exist in SMIv2. The next best choice would be to base them on the CounterBasedGauge64 textual convention

presented in RFC2856, but that is not possible either since SMIv2 allows only base types to be used in defining textual conventions. Therefore, the textual conventions presented in this memo are based directly on the Counter64 type, like those in RFC2856. They are subject to the following limitations:

- The MAX-ACCESS of objects defined using these textual conventions

  must be read-only, because the MAX-ACCESS of the underlying
  Counter64 type is read-only.

- No sub-range can be specified in object definitions using these

  textual conventions, because sub-ranges are not allowed on
  Counter64 objects.

- No DEFVAL clause can be specified in object definitions using

  these textual conventions, because DEFVALs are not allowed on
  Counter64 objects.

- Objects defined using these textual conventions cannot be used in

  an INDEX clause, because there is no INDEX clause mapping defined
  for objects of type Counter64.

Use of the textual conventions presented in this memo assumes the following:

- The agent supports 15 minute based history counters.

- The agent is capable of keeping a history of 96 intervals of 15

  minute performance data.

- The agent may optionally support performance data aggregating the

  history intervals.

- The agent will keep separate tables for the current interval, the

  history intervals, and the total aggregates.

Definitions

HC-PerfHist-TC-MIB DEFINITIONS ::= BEGIN

IMPORTS

   MODULE-IDENTITY,
   Counter64,
   Unsigned32,
   Integer32,
   mib-2                FROM SNMPv2-SMI
   TEXTUAL-CONVENTION   FROM SNMPv2-TC;

hcPerfHistTCMIB MODULE-IDENTITY

  LAST-UPDATED "200402030000Z" -- February 3, 2004
  ORGANIZATION "ADSLMIB Working Group"
  CONTACT-INFO "WG-email:  [email protected]
       Info:      https://www1.ietf.org/mailman/listinfo/adslmib
       Chair:     Mike Sneed
                  Sand Channel Systems
       Postal:    P.O.  Box 37324
                  Raleigh NC 27627-7324
                  USA
       Email:     [email protected]
       Phone:     +1 206 600 7022
       Co-editor: Bob Ray
                  PESA Switching Systems, Inc.
       Postal:    330-A Wynn Drive
                  Huntsville, AL 35805
                  USA
       Email:     [email protected]
       Phone:     +1 256 726 9200 ext.  142
       Co-editor: Rajesh Abbi
                  Alcatel USA
       Postal:    2301 Sugar Bush Road
                  Raleigh, NC 27612-3339
                  USA
       Email:     [email protected]
       Phone:     +1 919 850 6194
       "
   DESCRIPTION
       "This MIB Module provides Textual Conventions to be
        used by systems supporting 15 minute based performance
        history counts that require high-capacity counts.
        Copyright (C) The Internet Society (2004).  This version
        of this MIB module is part of RFC 3705: see the RFC
        itself for full legal notices."
       REVISION "200402030000Z" -- February 3, 2004
       DESCRIPTION "Initial version, published as RFC 3705."
       ::= { mib-2 107 }

HCPerfValidIntervals ::= TEXTUAL-CONVENTION

   STATUS  current
   DESCRIPTION
      "The number of near end intervals for which data was
      collected.  The value of an object with an
      HCPerfValidIntervals syntax will be 96 unless the
      measurement was (re-)started within the last 1440 minutes,
      in which case the value will be the number of complete 15
      minute intervals for which the agent has at least some data.
      In certain cases (e.g., in the case where the agent is a
      proxy) it is possible that some intervals are unavailable.
      In this case, this interval is the maximum interval number
      for which data is available."
   SYNTAX   Integer32 (0..96)

HCPerfInvalidIntervals ::= TEXTUAL-CONVENTION

   STATUS  current
   DESCRIPTION
      "The number of near end intervals for which no data is
      available.  The value of an object with an
      HCPerfInvalidIntervals syntax will typically be zero except
      in cases where the data for some intervals are not available
      (e.g., in proxy situations)."
   SYNTAX   Integer32 (0..96)

HCPerfTimeElapsed ::= TEXTUAL-CONVENTION

   STATUS  current
   DESCRIPTION
      "The number of seconds that have elapsed since the beginning
      of the current measurement period.  If, for some reason,
      such as an adjustment in the system's time-of-day clock or
      the addition of a leap second, the duration of the current
      interval exceeds the maximum value, the agent will return
      the maximum value.
      For 15 minute intervals, the range is limited to (0..899).
      For 24 hour intervals, the range is limited to (0..86399)."
   SYNTAX   Integer32 (0..86399)

HCPerfIntervalThreshold ::= TEXTUAL-CONVENTION

   STATUS   current
   DESCRIPTION
       "This convention defines a range of values that may be set
       in a fault threshold alarm control.  As the number of
       seconds in a 15-minute interval numbers at most 900,
       objects of this type may have a range of 0...900, where the
       value of 0 disables the alarm."
   SYNTAX   Unsigned32 (0..900)

HCPerfCurrentCount ::= TEXTUAL-CONVENTION

   STATUS  current
   DESCRIPTION
       "A gauge associated with a performance measurement in a
        current 15 minute measurement interval.  The value of an
        object with an HCPerfCurrentCount syntax starts from zero
        and is increased when associated events occur, until the
        end of the 15 minute interval.  At that time the value of
        the gauge is stored in the first 15 minute history
        interval, and the gauge is restarted at zero.  In the case
        where the agent has no valid data available for the
        current interval, the corresponding object instance is not
        available and upon a retrieval request a corresponding
        error message shall be returned to indicate that this
        instance does not exist.
        This count represents a non-negative integer, which
        may increase or decrease, but shall never exceed 2^64-1
        (18446744073709551615 decimal), nor fall below 0.  The
        value of an object with HCPerfCurrentCount syntax
        assumes its maximum value whenever the underlying count
        exceeds 2^64-1.  If the underlying count subsequently
        decreases below 2^64-1 (due, e.g., to a retroactive
        adjustment as a result of entering or exiting unavailable
        time), then the object's value also decreases.
        Note that this TC is not strictly supported in SMIv2,
        because the 'always increasing' and 'counter wrap'
        semantics associated with the Counter64 base type are not
        preserved.  It is possible that management applications
        which rely solely upon the (Counter64) ASN.1 tag to
        determine object semantics will mistakenly operate upon
        objects of this type as they would for Counter64 objects.
        This textual convention represents a limited and short-
        term solution, and may be deprecated as a long term
        solution is defined and deployed to replace it."
   SYNTAX  Counter64

HCPerfIntervalCount ::= TEXTUAL-CONVENTION

   STATUS  current
   DESCRIPTION
       "A gauge associated with a performance measurement in
        a previous 15 minute measurement interval.  In the case
        where the agent has no valid data available for a
        particular interval, the corresponding object instance is
        not available and upon a retrieval request a corresponding
        error message shall be returned to indicate that this
        instance does not exist.
        Let X be an object with HCPerfIntervalCount syntax.
        Let Y be an object with HCPerfCurrentCount syntax.
        Let Z be an object with HCPerfTotalCount syntax.
        Then, in a system supporting a history of n intervals with
        X(1) and X(n) the most and least recent intervals
        respectively, the following applies at the end of a 15
        minute interval:
           - discard the value of X(n)
           - the value of X(i) becomes that of X(i-1)
             for n >= i > 1
           - the value of X(1) becomes that of Y.
           - the value of Z, if supported, is adjusted.
        This count represents a non-negative integer, which
        may increase or decrease, but shall never exceed 2^64-1
        (18446744073709551615 decimal), nor fall below 0.  The
        value of an object with HCPerfIntervalCount syntax
        assumes its maximum value whenever the underlying count
        exceeds 2^64-1.  If the underlying count subsequently
        decreases below 2^64-1 (due, e.g., to a retroactive
        adjustment as a result of entering or exiting unavailable
        time), then the value of the object also decreases.
        Note that this TC is not strictly supported in SMIv2,
        because the 'always increasing' and 'counter wrap'
        semantics associated with the Counter64 base type are not
        preserved.  It is possible that management applications
        which rely solely upon the (Counter64) ASN.1 tag to
        determine object semantics will mistakenly operate upon
        objects of this type as they would for Counter64 objects.
        This textual convention represents a limited and short-
        term solution, and may be deprecated as a long term
        solution is defined and deployed to replace it."
   SYNTAX  Counter64

HCPerfTotalCount ::= TEXTUAL-CONVENTION

   STATUS  current
   DESCRIPTION
       "A gauge representing the aggregate of previous valid 15
        minute measurement intervals.  Intervals for which no
        valid data was available are not counted.
        This count represents a non-negative integer, which
        may increase or decrease, but shall never exceed 2^64-1
        (18446744073709551615 decimal), nor fall below 0.  The
        value of an object with HCPerfTotalCount syntax
        assumes its maximum value whenever the underlying count
        exceeds 2^64-1.  If the underlying count subsequently
        decreases below 2^64-1 (due, e.g., to a retroactive
        adjustment as a result of entering or exiting unavailable
        time), then the object's value also decreases.
        Note that this TC is not strictly supported in SMIv2,
        because the 'always increasing' and 'counter wrap'
        semantics associated with the Counter64 base type are not
        preserved.  It is possible that management applications
        which rely solely upon the (Counter64) ASN.1 tag to
        determine object semantics will mistakenly operate upon
        objects of this type as they would for Counter64 objects.
        This textual convention represents a limited and short-
        term solution, and may be deprecated as a long term
        solution is defined and deployed to replace it."
   SYNTAX  Counter64

END

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References

Normative References

RFC2119 Bradner, S., "Key words for use in RFCs to Indicate

         Requirement Levels", BCP 14, RFC 2119, March 1997.

RFC2578 McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,

         Rose, M. and S. Waldbusser, "Structure of Management
         Information Version 2 (SMIv2)", STD 58, RFC 2578, April
         1999.

RFC2579 McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,

         Rose, M. and S. Waldbusser, "Textual Conventions for
         SMIv2", STD 58, RFC 2579, April 1999.

RFC2580 McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,

         Rose, M. and S. Waldbusser, "Conformance Statements for
         SMIv2", STD 58, RFC 2580, April 1999.

Informative References

RFC3410 Case, J., Mundy, R., Partain, D. and B. Stewart,

         "Introduction and Applicability Statements for Internet-
         Standard Management Framework", RFC 3410, December 2002.

[T1.231] American National Standard for Telecommunications - Digital

         Hierarchy - Layer 1 In-Service Digital Transmission
         Performance Monitoring, ANSI T1.231-1997, September 1997.

RFC2026 Bradner, S., "The Internet Standards Process -- Revision

         3", BCP 9, RFC 2026, October 1996.

RFC2495 Fowler, D., "Definitions of Managed Objects for the DS1,

         E1, DS2 and E2 Interface Types", RFC 2495, January 1999.

RFC2496 Fowler, D., "Definitions of Managed Objects for the DS3/E3

         Interface Type", RFC 2496, January 1999.

RFC3592 Tesink, K., "Definitions of Managed Objects for the

         Synchronous Optical Network/Synchronous Digital Hierarchy
         (SONET/SDH) Interface Type", RFC 3592, November 2003.

RFC2662 Bathrick, G. and F. Ly, "Definitions of Managed Objects for

         the ADSL Lines",  RFC 2662, August 1999.

RFC2856 Bierman, A., McCloghrie, K. and R. Presuhn, "Textual

         Conventions for Additional High Capacity Data Types", RFC
         2856, June 2000.

RFC3276 Ray, B. and R. Abbi, "Definitions of Managed Objects for

         High Bit-rate DSL - 2nd Generation (HDSL2) and Single-Pair
         High-Speed Digital Subscriber Line (SHDSL) Lines", RFC
         3276, May 2002.

RFC3593 Tesink, K., "Textual Conventions for MIB Modules Using

         Performance History Based on 15 Minute Intervals", RFC
         3593,  November 2003.

Security Considerations

This module does not define any management objects. Instead, it defines a set of textual conventions which may be used by other MIB modules to define management objects.

Meaningful security considerations can only be written in the MIB modules that define management objects. This document has therefore no impact on the security of the Internet.

Acknowledgements

This document borrows tremendously from RFC3593 and RFC2856. As such, any credit for the text found within should be fully attributed to the authors of those documents.

Authors' Addresses

Bob Ray PESA Switching Systems, Inc. 330-A Wynn Drive Huntsville, AL 35805 USA

Phone: +1 256 726 9200 ext. 142 Fax: +1 256 726 9271 EMail: [email protected]

Rajesh Abbi Alcatel USA 2301 Sugar Bush Road Raleigh, NC 27612-3339 USA

Phone: +1 919 850 6194 EMail: [email protected]

Full Copyright Statement

Copyright (C) The Internet Society (2004). All Rights Reserved.

This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.

The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assignees.

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Acknowledgement

Funding for the RFC Editor function is currently provided by the Internet Society.