Network Working Group F. Strauss
Internet-Draft J. Schoenwaelder
Expires: January 18, 2002 TU Braunschweig
July 20, 2001
SMIng Core Modules
draft-ietf-sming-modules-02
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 18, 2002.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This memo presents an SMIng module that introduces core data types
such as counters, date and time related types, and various string
types. These definitions build on RFC 2578 and RFC 2579.
Strauss & Schoenwaelder Expires January 18, 2002 [Page 1]
Internet-Draft SMIng Modules July 2001
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. IETF-SMING . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 11
4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 12
A. OPEN ISSUES . . . . . . . . . . . . . . . . . . . . . . . . . 13
Full Copyright Statement . . . . . . . . . . . . . . . . . . . 14
Strauss & Schoenwaelder Expires January 18, 2002 [Page 2]
Internet-Draft SMIng Modules July 2001
1. Introduction
SMIng [1] modules are built on top of some core definitions. These
core definitions are imported from some "well-defined" core modules
described in this memo.
The IETF-SMING module defines a set of common SMIng data types.
These data types are generally applicable for modelling all areas of
management information. Among these types are counter types, string
types and date and time related types. This module is derived from
RFC 2578 [3] and [4].
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 [2].
2. IETF-SMING
module IETF-SMING {
organization "IETF Next Generation Structure of
Management Information Working Group (SMING)";
contact "Frank Strauss
TU Braunschweig
Bueltenweg 74/75
38106 Braunschweig
Germany
Phone: +49 531 391-3266
EMail: strauss@ibr.cs.tu-bs.de";
description "Core type definitions for SMIng. Several
type definitions are SMIng versions of
similar SMIv2 or SPPI definitions.";
revision {
date "2001-03-02";
description "Initial revision, published as RFC &rfc.number;.";
};
typedef Gauge32 {
type Unsigned32;
description
"The Gauge32 type represents a non-negative integer,
which may increase or decrease, but shall never
exceed a maximum value, nor fall below a minimum
Strauss & Schoenwaelder Expires January 18, 2002 [Page 3]
Internet-Draft SMIng Modules July 2001
value. The maximum value can not be greater than
2^32-1 (4294967295 decimal), and the minimum value
can not be smaller than 0. The value of a Gauge32
has its maximum value whenever the information
being modeled is greater than or equal to its
maximum value, and has its minimum value whenever
the information being modeled is smaller than or
equal to its minimum value. If the information
being modeled subsequently decreases below
(increases above) the maximum (minimum) value, the
Gauge32 also decreases (increases). (Note that
despite of the use of the term `latched' in the
original definition of this type, it does not
become `stuck' at its maximum or minimum value.)";
reference
"RFC 2578, Sections 2. and 7.1.7.";
};
typedef Counter32 {
type Unsigned32;
description
"The Counter32 type represents a non-negative integer
which monotonically increases until it reaches a
maximum value of 2^32-1 (4294967295 decimal), when it
wraps around and starts increasing again from zero.
Counters have no defined `initial' value, and thus, a
single value of a Counter has (in general) no
information content. Discontinuities in the
monotonically increasing value normally occur at
re-initialization of the management system, and at
other times as specified in the description of an
attribute using this type. If such other times can
occur, for example, the creation of a class
instance that contains an attribute of type Counter32
at times other than re-initialization, then
a corresponding attribute should be defined, with an
appropriate type, to indicate the last discontinuity.
Examples of appropriate types include: TimeStamp,
DateAndTime or TimeTicks (other types defined in this
module).
The value of the access statement for attributes with
a type value of Counter32 should be either `readonly'
or `eventonly'.
A default statement should not be used for attributes
with a type value of Counter32.";
Strauss & Schoenwaelder Expires January 18, 2002 [Page 4]
Internet-Draft SMIng Modules July 2001
reference
"RFC 2578, Sections 2. and 7.1.6.";
};
typedef Gauge64 {
type Unsigned64;
description
"The Gauge64 type represents a non-negative integer,
which may increase or decrease, but shall never
exceed a maximum value, nor fall below a minimum
value. The maximum value can not be greater than
2^64-1 (18446744073709551615), and the minimum value
can not be smaller than 0. The value of a Gauge64
has its maximum value whenever the information
being modeled is greater than or equal to its
maximum value, and has its minimum value whenever
the information being modeled is smaller than or
equal to its minimum value. If the information
being modeled subsequently decreases below
(increases above) the maximum (minimum) value, the
Gauge64 also decreases (increases). (Note that
despite of the use of the term `latched' in the
original definition of this type, it does not
become `stuck' at its maximum or minimum value.)";
};
typedef Counter64 {
type Unsigned64;
description
"The Counter64 type represents a non-negative integer
which monotonically increases until it reaches a
maximum value of 2^64-1 (18446744073709551615), when
it wraps around and starts increasing again from zero.
Counters have no defined `initial' value, and thus, a
single value of a Counter has (in general) no
information content. Discontinuities in the
monotonically increasing value normally occur at
re-initialization of the management system, and at
other times as specified in the description of an
attribute using this type. If such other times can
occur, for example, the creation of a class
instance that contains an attribute of type Counter32
at times other than re-initialization, then
a corresponding attribute should be defined, with an
appropriate type, to indicate the last discontinuity.
Examples of appropriate types include: TimeStamp,
DateAndTime or TimeTicks (other types defined in this
Strauss & Schoenwaelder Expires January 18, 2002 [Page 5]
Internet-Draft SMIng Modules July 2001
module).
The value of the access statement for attributes with
a type value of Counter64 should be either `readonly'
or `eventonly'.
A default statement should not be used for attributes
with a type value of Counter64.";
reference
"RFC 2578, Sections 2. and 7.1.10.";
};
typedef Opaque {
type OctetString;
status obsolete;
description
"******* THIS TYPE DEFINITION IS OBSOLETE *******
The Opaque type is provided solely for
backward-compatibility, and shall not be used for
newly-defined attributes and derived types.
The Opaque type supports the capability to pass
arbitrary ASN.1 syntax. A value is encoded using
the ASN.1 Basic Encoding Rules into a string of
octets. This, in turn, is encoded as an
OctetString, in effect `double-wrapping' the
original ASN.1 value.
Note that a conforming implementation need only be
able to accept and recognize opaquely-encoded data.
It need not be able to unwrap the data and then
interpret its contents.
A requirement on `standard' modules is that no
attribute may have a type value of Opaque and no
type may be derived from the Opaque type.";
reference
"RFC 2578, Sections 2. and 7.1.9.";
};
typedef IpAddress {
type OctetString (4);
status deprecated;
description
"******* THIS TYPE DEFINITION IS DEPRECATED *******
The IpAddress type represents a 32-bit internet
Strauss & Schoenwaelder Expires January 18, 2002 [Page 6]
Internet-Draft SMIng Modules July 2001
IPv4 address. It is represented as an OctetString
of length 4, in network byte-order.
Note that the IpAddress type is present for
historical reasons. IPv4 and IPv6 addresses should
be represented using the InetNetworkEndpoint class
defined in the IETF-INET module.";
reference
"RFC 2578, Sections 2. and 7.1.5.";
};
typedef TimeTicks {
type Unsigned32;
description
"The TimeTicks type represents a non-negative
integer which represents the time, modulo 2^32
(4294967296 decimal), in hundredths of a second
between two epochs. When attributes are defined which
use this type, the description of the attribute
identifies both of the reference epochs.
For example, the TimeStamp type (defined in this
module) is based on the TimeTicks type.";
reference
"RFC 2578, Sections 2. and 7.1.8.";
};
typedef TimeStamp {
type TimeTicks;
description
"The value of the sysUpTime attribute at which a specific
occurrence happened. The specific occurrence must be
defined in the description of any attribute defined using this
type. When the specific occurrence occurred prior to the
last time sysUpTime was zero, then the TimeStamp value is
zero. Note that this requires all TimeStamp values to be
reset to zero when the value of sysUpTime reaches 497+ days
and wraps around to zero.";
reference
"RFC 2579, Section 2.";
};
typedef TimeInterval {
type Integer32 (0..2147483647);
description
"A period of time, measured in units of 0.01 seconds.
The TimeInterval type uses Integer32 rather than
Strauss & Schoenwaelder Expires January 18, 2002 [Page 7]
Internet-Draft SMIng Modules July 2001
Unsigned32 for compatibility with RFC 2579.";
reference
"RFC 2579, Section 2.";
};
typedef DateAndTime {
type OctetString (8 | 11);
default 0x0000000000000000000000;
format "2d-1d-1d,1d:1d:1d.1d,1a1d:1d";
description
"A date-time specification.
field octets contents range
----- ------ -------- -----
1 1-2 year* 0..65536
2 3 month 1..12
3 4 day 1..31
4 5 hour 0..23
5 6 minutes 0..59
6 7 seconds 0..60
(use 60 for leap-second)
7 8 deci-seconds 0..9
8 9 direction from UTC '+' / '-'
9 10 hours from UTC* 0..13
10 11 minutes from UTC 0..59
* Notes:
- the value of year is in big-endian encoding
- daylight saving time in New Zealand is +13
For example, Tuesday May 26, 1992 at 1:30:15 PM EDT would
be displayed as:
1992-5-26,13:30:15.0,-4:0
Note that if only local time is known, then timezone
information (fields 8-10) is not present.
The two special values of 8 or 11 zero bytes denote an
unknown date-time specification.";
reference
"RFC 2579, Section 2.";
};
typedef TruthValue {
type Enumeration (true(1), false(2));
description
"Represents a boolean value.";
Strauss & Schoenwaelder Expires January 18, 2002 [Page 8]
Internet-Draft SMIng Modules July 2001
reference
"RFC 2579, Section 2.";
};
typedef PhysAddress {
type OctetString;
format "1x:";
description
"Represents media- or physical-level addresses.";
reference
"RFC 2579, Section 2.";
};
typedef MacAddress {
type OctetString (6);
format "1x:";
description
"Represents an IEEE 802 MAC address represented in the
`canonical' order defined by IEEE 802.1a, i.e., as if it
were transmitted least significant bit first, even though
802.5 (in contrast to other 802.x protocols) requires MAC
addresses to be transmitted most significant bit first.";
reference
"RFC 2579, Section 2.";
};
// The DisplayString definition below does not impose a size
// restriction and is thus not the same as the DisplayString
// definition in RFC 2579. The DisplayString255 definition is
// provided for mapping purposes.
typedef DisplayString {
type OctetString;
format "1a";
description
"Represents textual information taken from the NVT ASCII
character set, as defined in pages 4, 10-11 of RFC 854.
To summarize RFC 854, the NVT ASCII repertoire specifies:
- the use of character codes 0-127 (decimal)
- the graphics characters (32-126) are interpreted as
US ASCII
- NUL, LF, CR, BEL, BS, HT, VT and FF have the special
meanings specified in RFC 854
Strauss & Schoenwaelder Expires January 18, 2002 [Page 9]
Internet-Draft SMIng Modules July 2001
- the other 25 codes have no standard interpretation
- the sequence 'CR LF' means newline
- the sequence 'CR NUL' means carriage-return
- an 'LF' not preceded by a 'CR' means moving to the
same column on the next line.
- the sequence 'CR x' for any x other than LF or NUL is
illegal. (Note that this also means that a string may
end with either 'CR LF' or 'CR NUL', but not with CR.)
";
};
typedef DisplayString255 {
type DisplayString (0..255);
description
"A DisplayString with a maximum length of 255 characters.
Any attribute defined using this syntax may not exceed 255
characters in length.
The DisplayString255 type has the same semantics as the
DisplayString textual convention defined in RFC 2579.";
reference
"RFC 2579, Section 2.";
};
// The Utf8String and Utf8String255 definitions below facilitate
// internationalization. The definition is consistent with the
// definition of SnmpAdminString in RFC 2571.
typedef Utf8String {
type OctetString;
format "65535t"; // is there a better way ?
description
"A human readable string represented using the ISO/IEC IS
10646-1 character set, encoded as an octet string using
the UTF-8 transformation format described in RFC 2279.
Since additional code points are added by amendments to
the 10646 standard from time to time, implementations must
be prepared to encounter any code point from 0x00000000 to
0x7fffffff. Byte sequences that do not correspond to the
valid UTF-8 encoding of a code point or are outside this
range are prohibited.
The use of control codes should be avoided. When it is
Strauss & Schoenwaelder Expires January 18, 2002 [Page 10]
Internet-Draft SMIng Modules July 2001
necessary to represent a newline, the control code
sequence CR LF should be used.
The use of leading or trailing white space should be
avoided.
For code points not directly supported by user interface
hardware or software, an alternative means of entry and
display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8
encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single
character / code point; thus the length of a Utf8String in
octets may be different from the number of characters
encoded. Similarly, size constraints refer to the number
of encoded octets, not the number of characters
represented by an encoding.
Note that the size of an Utf8String is measured in octets,
not characters.";
};
typedef Utf8String255 {
type Utf8String (0..255);
format "255t";
description
"A Utf8String with a maximum length of 255 octets. Note
that the size of an Utf8String is measured in octets, not
characters.";
};
identity null {
description
"An identity used to represent null pointer values.";
};
};
3. Security Considerations
This module does not define any management objects. Instead, it
defines a set of SMIng types and classes which may be used by other
SMIng modules to define management objects. These data definitions
Strauss & Schoenwaelder Expires January 18, 2002 [Page 11]
Internet-Draft SMIng Modules July 2001
have no security impact on the Internet.
4. Acknowledgments
Some definitions in this document are derived from RFC 2578 [3] and
RFC 2579 [4], which were written by K. McCloghrie, D. Perkins, J.
Schoenwaelder, J. Case, M. Rose, and S. Waldbusser.
References
[1] Strauss, F. and J. Schoenwaelder, "SMIng - Next Generation
Structure of Management Information", draft-ietf-sming-02.txt,
July 2001.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, BCP 14, March 1997.
[3] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
M. and S. Waldbusser, "Structure of Management Information
Version 2 (SMIv2)", RFC 2578, STD 59, April 1999.
[4] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
M. and S. Waldbusser, "Textual Conventions for SMIv2", RFC 2579,
STD 59, April 1999.
Authors' Addresses
Frank Strauss
TU Braunschweig
Bueltenweg 74/75
38106 Braunschweig
Germany
Phone: +49 531 391-3266
EMail: strauss@ibr.cs.tu-bs.de
URI: http://www.ibr.cs.tu-bs.de/
Juergen Schoenwaelder
TU Braunschweig
Bueltenweg 74/75
38106 Braunschweig
Germany
Phone: +49 531 391-3289
EMail: schoenw@ibr.cs.tu-bs.de
URI: http://www.ibr.cs.tu-bs.de/
Strauss & Schoenwaelder Expires January 18, 2002 [Page 12]
Internet-Draft SMIng Modules July 2001
Appendix A. OPEN ISSUES
What else is missing? - There might be more core type or class
definitions that should go into the IETF-SMING module. Things
that come to mind are types for Roles and RoleCombinations or
types for Tags and TagLists.
Split Core Module? - Should the SMIng core module be split into
several smaller modules each focussing on a specific aspect (e.g.
strings, date and time, ...)?
TimeStamp - The description of the TimeStamp type builds on
sysUpTime.
TimeInterval - Define TimeInterval based on Unsigned32 and remove
the last sentence from the description?
Ugly Formats like `255t' - A better solution for e.g. the `255t'
length restriction of Utf8String255?
Class Definitions - Maybe, we should define useful classes, like one
which combines RowStatus and StorageType (and perhaps even an
OwnerString)?
Strauss & Schoenwaelder Expires January 18, 2002 [Page 13]
Internet-Draft SMIng Modules July 2001
Full Copyright Statement
Copyright (C) The Internet Society (2001). 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.
Strauss & Schoenwaelder Expires January 18, 2002 [Page 14]
