Network Working Group B. Ray

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.

Table of Contents

1. The Internet-Standard Management Framework . . . . . . . . . . 2
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Intellectual Property Statement. . . . . . . . . . . . . . . . 8
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Normative References . . . . . . . . . . . . . . . . . . 8
5.2. Informative References . . . . . . . . . . . . . . . . . 9
6. Security Considerations. . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
8. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 10
9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 11

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1. 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].

2. 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

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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.

3. Definitions

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

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

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RFC 3705 High Capacity Perfhist TC MIB February 2004

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

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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

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"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.

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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

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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

4. 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 in BCP-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.

5. References

5.1. Normative References

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

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[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.

5.2. 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.

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RFC 3705 High Capacity Perfhist TC MIB February 2004

[RFC3593] Tesink, K., "Textual Conventions for MIB Modules Using
Performance History Based on 15 Minute Intervals", RFC
3593, November 2003.

6. 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.

7. 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.

8. 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]

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RFC 3705 High Capacity Perfhist TC MIB February 2004

9. 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.

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.

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