Movatterモバイル変換

Network Working Group                                     K. Tesink, Ed.Request for Comments: 3593                        Telcordia TechnologiesObsoletes:2493                                           September 2003Category: Standards TrackTextual Conventions for MIB Modules Using Performance HistoryBased on 15 Minute IntervalsStatus 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 (2003).  All Rights Reserved.Abstract   This document defines a set of Textual Conventions for MIB modules   that make use of performance history data based on 15 minute   intervals.   This memo replacesRFC 2493.  Changes relative toRFC 2493 are   summarized in the MIB module's REVISION clause.Table of Contents1.  Introduction .................................................22.  Note on Invalid Data and Proxies .............................23.  Note on xyzTimeElapsed .......................................34.  Note on xyzValidIntervals ....................................35.  Definitions ..................................................46.  Acknowledgments ..............................................87.  References ...................................................87.1.  Normative References ...................................87.2.  Informative References .................................88.  Security Considerations ......................................99.  Intellectual Property Statement ..............................910. Editor's Address .............................................911. Full Copyright Statement .....................................10Tesink                      Standards Track                     [Page 1]

RFC 3593        15 Minute Based Performance History TCs   September 20031.  Introduction   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 that represents the managed   equipment, including:   0  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.   0  The agent allocates events to 'buckets' where each bucket      represents an interval of time.   Telecommunications equipment often makes use of the latter strategy.   See [3][4][5][7][8] for examples.  In particular, for this equipment   it is common that history data is maintained by the agent in terms of   fifteen minute intervals.   This memo does not attempt to compare the relative merits of   different strategies used to obtain history data.  Differences may   include polling policy, the amount of management traffic between   manager and agent, agent simplicity, and 'data currentness' of the   data obtained by the manager.  MIB designers should consider these   aspects when choosing a particular strategy in a MIB design.   Instead, this memo provides definitions that can be used in MIB   modules that require history data based on fifteen minute intervals.   When designing a MIB module, it is often useful to define new types   similar to those defined in the SMI [2].  In comparison to a type   defined in the SMI, each of these new types has a different name, a   similar syntax, but more precise semantics.  These newly defined   types are termed textual conventions, and are used for the   convenience of humans reading the MIB module.  This is done through   Textual Conventions as defined inRFC 2579 [1].  It is the purpose of   this document to define the set of textual conventions to be used   when performance history based on 15 minute intervals is kept.  The   performance history textual conventions defined in this memo are   based on 32 bit counts.  For high capacity performance history counts   see [9].2.  Note on Invalid Data and Proxies   In this document, the word proxy indicates an application which   receives SNMP messages and replies to them on behalf of the devices   where the actual implementation resides, e.g., DS3/E3 interfaces.   The proxy will have already collected the information about the   DS3/E3 interfaces into its local database and may not necessarilyTesink                      Standards Track                     [Page 2]

RFC 3593        15 Minute Based Performance History TCs   September 2003   forward requests to the actual DS3/E3 interface.  It is expected in   such an application that there are periods of time where the proxy is   not communicating with the DS3/E3 interfaces.  In these instances,   the proxy will not necessarily have up-to-date configuration   information, and will most likely have missed the collection of some   data.  Missed data collection may result in some intervals in the   interval table being unavailable.3.  Note on xyzTimeElapsed   While xyzTimeElapsed is defined as having a maximum, there may be   cases (e.g., an adjustment in the system's time-of-day clock) where   the actual value of the current interval would exceed this maximum   value.   Suppose that an agent which aligns its 15-minute measurement   intervals to 15-minute time-of-day ("wall clock") boundaries has a   time-of-day clock that systematically gains time, and that a manager   periodically corrects the clock by setting it back.   It is assumed that the agent's time-of-day clock is reasonably   accurate, say within a few seconds per day.  Thus, the manager's   periodic clock adjustments will normally be small, and if done   frequently enough, need not ever exceed 10 seconds.  In this case,   all interval durations will be within the allowed tolerance and none   need be marked invalid, _if_ the ANSI procedure of ending measurement   intervals at 15-minute time-of-day boundaries is followed [6].   If the time-of-day clock is systematically adjusted in small   increments, then always ending measurement intervals at 15-minute   time-of-day boundaries will result, in the long term, in the correct   number of intervals with the correct average duration, irrespective   of whether the clock is moved ahead or moved back.  Thus, if for some   reason, such as an adjustment in the system's time-of-day clock, the   current interval exceeds the maximum value, it is considered   acceptable that the agent will return the maximum value.4.  Note on xyzValidIntervals   The overall constraint on <n> is 1 =< n =< 96.  Any additional   constraints on n must be defined in the DESCRIPTION clause (e.g., see   [5]).Tesink                      Standards Track                     [Page 3]

RFC 3593        15 Minute Based Performance History TCs   September 20035.  Definitions   PerfHist-TC-MIB DEFINITIONS ::= BEGIN   IMPORTS      MODULE-IDENTITY,      Gauge32, mib-2          FROM SNMPv2-SMI      TEXTUAL-CONVENTION          FROM SNMPv2-TC;   perfHistTCMIB MODULE-IDENTITY        LAST-UPDATED "200308130000Z"        ORGANIZATION "IETF AToM MIB WG"        CONTACT-INFO           "WG charter:http://www.ietf.org/html.charters/atommib-charter.html            Mailing Lists:              General Discussion: atommib@research.telcordia.com              To Subscribe: atommib-request@research.telcordia.com            Editor:  Kaj Tesink            Postal:  Telcordia Technologies                     331 Newman Springs Road                     Red Bank, NJ 07701                     USA            Tel:     +1 732 758 5254            E-mail:  kaj@research.telcordia.com"        DESCRIPTION         "This MIB Module provides Textual Conventions          to be used by systems supporting 15 minute          based performance history counts.          Copyright (C) The Internet Society (2003).          This version of this MIB module is part ofRFC 3593;  see the RFC itself for full          legal notices."        REVISION      "200308130000Z"        DESCRIPTION         "Contact information and references updated.          No technical changes have been applied.          Published asRFC 3593."        REVISION      "199811071100Z"        DESCRIPTION         "TheRFC 2493 version of this MIB module."        ::= { mib-2 58 }Tesink                      Standards Track                     [Page 4]

RFC 3593        15 Minute Based Performance History TCs   September 2003   -- The Textual Conventions defined below are organized   -- alphabetically   -- Use of these TCs assumes the following:   -- 0  The agent supports 15 minute based history   --    counters.   -- 0  The agent is capable of keeping a history of n   --    intervals of 15 minute performance data.  The   --    value of n is defined by the specific MIB   --    module but shall be 0 < n =< 96.   -- 0  The agent may optionally support performance   --    data aggregating the history intervals.   -- 0  The agent will keep separate tables for the   --    current interval, the history intervals, and   --    the total aggregates.   -- 0  The agent will keep the following objects.   --    If performance data is kept for multiple instances   --    of a measured entity, then   --    these objects are applied to each instance of   --    the measured entity (e.g., interfaces).   --   -- xyzTimeElapsed OBJECT-TYPE   --       SYNTAX  INTEGER (0..899)   --       MAX-ACCESS  read-only   --       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, the current interval   --       exceeds the maximum value, the agent will return   --       the maximum value."   --       ::= { xxx }   -- xyzValidIntervals OBJECT-TYPE   --       SYNTAX  INTEGER (0..<n>)   --       MAX-ACCESS  read-only   --       STATUS  current   --       DESCRIPTION   --       "The number of previous near end intervals   --       for which data was collected.   --          [ The overall constraint on <n> is 1 =< n =< 96; ]   --          [ Define any additional constraints on <n> here. ]   --       The value will be <n> unless the measurement was   --       (re-)started within the last (<n>*15) 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 caseTesink                      Standards Track                     [Page 5]

RFC 3593        15 Minute Based Performance History TCs   September 2003   --       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."   --       ::= { xxx }   -- xyzInvalidIntervals OBJECT-TYPE   --     SYNTAX  INTEGER (0..<n>)   --     MAX-ACCESS  read-only   --     STATUS  current   --     DESCRIPTION   --       "The number of intervals in the range from   --        0 to xyzValidIntervals for which no   --        data is available.  This object will typically   --        be zero except in cases where the data for some   --        intervals are not available (e.g., in proxy   --        situations)."   --       ::= { xxx }   PerfCurrentCount ::= TEXTUAL-CONVENTION         STATUS  current         DESCRIPTION            "A counter associated with a             performance measurement in a current 15             minute measurement interval.  The value             of this counter 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 counter is             stored in the first 15 minute history             interval, and the CurrentCount 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 (for example, a noSuchName             error for SNMPv1 and a noSuchInstance for             SNMPv2 GET operation)."          SYNTAX  Gauge32Tesink                      Standards Track                     [Page 6]

RFC 3593        15 Minute Based Performance History TCs   September 2003   PerfIntervalCount ::= TEXTUAL-CONVENTION         STATUS  current         DESCRIPTION            "A counter 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 (for example, a noSuchName             error for SNMPv1 and a noSuchInstance for             SNMPv2 GET operation).             In a system supporting             a history of n intervals with             IntervalCount(1) and IntervalCount(n) the             most and least recent intervals             respectively, the following applies at             the end of a 15 minute interval:             - discard the value of IntervalCount(n)             - the value of IntervalCount(i) becomes that               of IntervalCount(i-1) for n >= i > 1             - the value of IntervalCount(1) becomes that               of CurrentCount             - the TotalCount, if supported, is adjusted."          SYNTAX  Gauge32   PerfTotalCount ::= TEXTUAL-CONVENTION         STATUS  current         DESCRIPTION            "A counter associated with a             performance measurements aggregating the             previous valid 15 minute measurement             intervals.  (Intervals for which no valid             data was available are not counted)"          SYNTAX  Gauge32   ENDTesink                      Standards Track                     [Page 7]

RFC 3593        15 Minute Based Performance History TCs   September 20036.  Acknowledgments   This document is a product of the AToM MIB Working Group.  The editor   would like to acknowledge Mike Heard for his many valuable   contributions to this memo.7.  References7.1.  Normative References   [1]  McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,        M. and S. Waldbusser, "Textual Conventions for SMIv2", STD 58,RFC 2579, April 1999.   [2]  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 1999.7.2.  Informative References   [3]  Fowler, D., "Definitions of Managed Objects for the DS1, E1, DS2        and E2 Interface Types",RFC 2495, January 1999.   [4]  Fowler, D., "Definitions of Managed Objects for the DS3/E3        Interface Type",RFC 2496, January 1999.   [5]  Tesink, K., "Definitions of Managed Objects for the Synchronous        Optical Network/Synchronous Digital Hierarchy (SONET/SDH)        Interface Type",RFC 3592, September 2003.   [6]  American National Standard for Telecommunications - Digital        Hierarchy - Layer 1 In-Service Digital Transmission Performance        Monitoring, ANSI T1.231-1997, September 1997.   [7]  Bathrick, G. and F. Ly, "Definitions of Managed Objects for the        ADSL Lines",RFC 2662, August 1999.   [8]  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.   [9]  Ray, B. and R. Abbi, "High Capacity Textual Conventions for MIB        Modules Using Performance History Based on 15 Minute Intervals",        Work in Progress.Tesink                      Standards Track                     [Page 8]

RFC 3593        15 Minute Based Performance History TCs   September 20038.  Security Considerations   This memo defines textual conventions for use in other MIB modules.   Security issues for these MIB modules are addressed in the memos   defining those modules.9.  Intellectual Property Statement   The IETF takes no position regarding the validity or scope of any   intellectual property or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; neither does it represent that it   has made any effort to identify any such rights.  Information on the   IETF's procedures with respect to rights in standards-track and   standards-related documentation can be found inBCP-11.  Copies of   claims of rights made available for publication and any assurances of   licenses to be made available, or the result of an attempt made to   obtain a general license or permission for the use of such   proprietary rights by implementors or users of this specification can   be obtained from the IETF Secretariat.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights which may cover technology that may be required to practice   this standard.  Please address the information to the IETF Executive   Director.10.  Editor's Address   Kaj Tesink   Telcordia Technologies   331 Newman Springs Road   P.O. Box 7020   Red Bank, NJ  07701-7020   Phone: +1 732 758 5254   EMail: kaj@research.telcordia.comTesink                      Standards Track                     [Page 9]

RFC 3593        15 Minute Based Performance History TCs   September 200311.  Full Copyright Statement   Copyright (C) The Internet Society (2003).  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 assigns.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Tesink                      Standards Track                    [Page 10]