--- 1/draft-ietf-opsawg-smi-datatypes-in-xsd-05.txt 2010-03-01 17:11:15.000000000 +0100
+++ 2/draft-ietf-opsawg-smi-datatypes-in-xsd-06.txt 2010-03-01 17:11:15.000000000 +0100
@@ -1,18 +1,28 @@
-Network Working Group B. Natale
-Internet-Draft MITRE
-Intended status: Standards Track March 27, 2009
-Expires: September 27, 2009
+Network Working Group M. Ellison
+Internet-Draft Ellison Software Consulting
+Intended status: Standards Track B. Natale
+Expires: September 2, 2010 MITRE
+ March 1, 2010
Expressing SNMP SMI Datatypes in XML Schema Definition Language
- draft-ietf-opsawg-smi-datatypes-in-xsd-05.txt
+ draft-ietf-opsawg-smi-datatypes-in-xsd-06.txt
+
+Abstract
+
+ This memo defines the IETF standard expression of Structure of
+ Management Information (SMI) base datatypes in Extensible Markup
+ Language (XML) Schema Definition (XSD) language. The primary
+ objective of this memo is to enable the production of XML documents
+ that are as faithful to the SMI as possible, using XSD as the
+ validation mechanism.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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.
@@ -21,175 +31,180 @@
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 September 27, 2009.
+ This Internet-Draft will expire on September 2, 2010.
Copyright Notice
- Copyright (c) 2009 IETF Trust and the persons identified as the
+ Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
- Provisions Relating to IETF Documents in effect on the date of
- publication of this document (http://trustee.ietf.org/license-info).
- Please review these documents carefully, as they describe your rights
- and restrictions with respect to this document.
-
-Abstract
-
- This memo defines the IETF standard expression of Structure of
- Management Information (SMI) base datatypes in Extensible Markup
- Language (XML) Schema Definition (XSD) language. The primary
- objective of this memo is to enable the production of XML documents
- that are as faithful to the SMI as possible, using XSD as the
- validation mechanism.
+ Provisions Relating to IETF Documents
+ (http://trustee.ietf.org/license-info) in effect on the date of
+ publication of this document. Please review these documents
+ carefully, as they describe your rights and restrictions with respect
+ to this document. Code Components extracted from this document must
+ include Simplified BSD License text as described in Section 4.e of
+ the Trust Legal Provisions and are provided without warranty as
+ described in the BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. XSD for SMI Base Datatypes . . . . . . . . . . . . . . . . . . 7
- 5. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 10
- 5.1. Numeric Datatypes . . . . . . . . . . . . . . . . . . . . 10
- 5.2. OctetString . . . . . . . . . . . . . . . . . . . . . . . 10
- 5.3. Opaque . . . . . . . . . . . . . . . . . . . . . . . . . . 11
- 5.4. IpAddress . . . . . . . . . . . . . . . . . . . . . . . . 12
- 5.5. ObjectIdentifier . . . . . . . . . . . . . . . . . . . . . 12
- 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
- 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
- 7.1. SMI Base Datatypes Namespace Registration . . . . . . . . 14
- 7.2. SMI Base Datatypes Schema Registration . . . . . . . . . . 14
- 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15
- 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
- 9.1. Normative References . . . . . . . . . . . . . . . . . . . 16
- 9.2. Informational References . . . . . . . . . . . . . . . . . 16
- Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 17
+ 5. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 11
+ 5.1. Numeric Datatypes . . . . . . . . . . . . . . . . . . . . 11
+ 5.2. OctetString . . . . . . . . . . . . . . . . . . . . . . . 11
+ 5.3. Opaque . . . . . . . . . . . . . . . . . . . . . . . . . . 12
+ 5.4. IpAddress . . . . . . . . . . . . . . . . . . . . . . . . 13
+ 5.5. ObjectIdentifier . . . . . . . . . . . . . . . . . . . . . 13
+ 6. Security Considerations . . . . . . . . . . . . . . . . . . . 15
+ 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
+ 7.1. SMI Base Datatypes Namespace Registration . . . . . . . . 16
+ 7.2. SMI Base Datatypes Schema Registration . . . . . . . . . . 16
+ 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
+ 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
+ 9.1. Normative References . . . . . . . . . . . . . . . . . . . 18
+ 9.2. Informational References . . . . . . . . . . . . . . . . . 18
+ Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
- Numerous uses exist -- both within and outside the traditional IETF
- network management community -- for the expression of management
- information described in and accessible via SMI Management
- Information Base (MIB) modules as XML documents [XML]. For example,
- XML-based management applications which want to incorporate MIB
- modules as data models and/or to access MIB module instrumentation
- via gateways to SNMP agents will benefit from an IETF standard
- mapping of SMI datatypes to XML documents via XSD.
+ Numerous use cases exist for expressing the management information
+ described by SMI Management Information Base (MIB) modules in XML
+ [XML]. Potential use cases reside both outside and within the
+ traditional IETF network management community. For example,
+ developers of some XML-based management applications may want to
+ incorporate the rich set of data models provided by MIB modules.
+ Developers of other XML-based management applications may want to
+ access MIB module instrumentation via gateways to SNMP agents. Such
+ applications benefit from the IETF standard mapping of SMI datatypes
+ to XML datatypes via XSD [XMLSchema], [XSDDatatypes].
- MIB data models are described using SMIv2 [RFC2578] and, for legacy
- MIBs, SMIv1 [RFC1155]. MIB data is conveyed in variable bindings
- ("varbinds") within protocol data units (PDUs) within SNMP messages
- using the base/primitive datatypes defined in the SMI.
+ MIB modules use SMIv2 [RFC2578] to describe data models. For legacy
+ MIB modules, SMIv1 [RFC1155] was used. MIB data conveyed in variable
+ bindings ("varbinds") within protocol data units (PDUs) of SNMP
+ messages use the primitive, base datatypes defined by the SMI.
- The SMI allows for creation of derivative datatypes, termed "textual
- conventions" ("TCs"), each of which has a unique name, a syntax which
- is or refines a primitive SMI datatype, and relatively precise
- application-level semantics. TCs are used principally to facilitate
- correct application-level handling of MIB data and for the
- convenience of humans reading MIB modules and appropriately rendered
- MIB data output. Values in varbinds corresponding to MIB objects
- with TC syntaxes are always encoded as the primitive SMI datatype
- underlying the TC syntax. Thus, the XSD mappings defined in this
- memo will support MIB objects with TC syntax as well as those with
- base SMI syntax.
+ The SMI allows for the creation of derivative datatypes, "textual
+ conventions" ("TCs") [RFC2579]. A TC has a unique name, has a syntax
+ that either refines or is a base SMI datatype and has relatively
+ precise application-level semantics. TCs facilitate correct
+ application-level handling of MIB data, improve readability of MIB
+ modules by humans and support appropriate renderings of MIB data.
- Various independent schemes have been devised for expressing the SMI
- datatypes in XSD [XMLSchema]. These schemes have exhibited a degree
- of commonality (especially concerning the numeric SMI datatypes), but
- also sufficient differences (especially concerning the non-numeric
- SMI datatypes) to preclude uniformity and general interoperability.
+ Values in varbinds corresponding to MIB objects defined with TC
+ syntax are always encoded as the base SMI datatype underlying the TC
+ syntax. Thus, the XSD mappings defined in this memo provide support
+ for values of MIB objects defined with TC syntax as well as for
+ values of MIB objects defined with base SMI syntax.
- The primary purpose of this memo is to define a standard expression
- of SMI base datatypes in XSD to ensure fidelity, consistency, and
- general interoperability in this respect. Internet operators,
- management tool developers, and users will benefit from the wider
- selection of management tools and the greater degree of unified
- management -- with attendant improvements in timeliness and accuracy
- of management information -- which such a standard facilitates.
+ Various independent schemes have been devised for expressing SMI
+ datatypes in XSD. These schemes exhibit a degree of commonality,
+ especially concerning numeric SMI datatypes, but these schemes also
+ exhibit sufficient differences, especially concerning the non-numeric
+ SMI datatypes, precluding uniformity of expression and general
+ interoperability.
- On its own, this memo specifies the IETF standard way to render SMI
- data values carried in SNMP messages as XML in a faithful,
- consistent, and interoperable way.
+ Throughout this memo, the term "fidelity" refers to the quality of an
+ accurate, consistent representation of SMI data values and the term
+ "faithful" refers to the quality of reliably reflecting the semantics
+ of SMI data values. Thus defined, the characteristics of fidelity
+ and being faithful are essential to uniformity of expression and
+ general interoperability in the XML representation of SMI data
+ values.
- Certain XML-based applications will find this specification
- sufficient for their purposes. Other XML applications may need to
- make more complete reuse of existing MIB modules, requiring standard
- XSDs for TCs [RFC2579] and MIB structure [RFC2578]. Documents
- supporting those requirements are planned, but have not been produced
- at the time of this writing.
+ The primary purpose of this memo is to define the standard expression
+ of SMI base datatypes in XML documents that is both uniform and
+ interoperable. This standard expression enables Internet operators,
+ management application developers, and users to benefit from a wider
+ range of management tools and to benefit from a greater degree of
+ unified management. Thus, standard expression enables and
+ facilitates improvements to the timeliness, accuracy and utility of
+ management information.
- The objective of this memo, and of any future related specifications
- that might be produced, is to define the XSD equivalent
- [XSDDatatypes] of SMIv2 (STD58) to encourage XML-based protocols to
- carry, and XML-based applications to use, the information modeled in
- SMIv2-compliant MIB modules.
+ The overall objective of this memo, and of any related future memos
+ as may be published, is to define the XSD equivalent [XSDDatatypes]
+ of SMIv2 (STD58) and to encourage XML-based protocols to carry, and
+ XML-based applications to use, the management information defined in
+ SMIv2-compliant MIB modules. The use of a standard mapping from
+ SMIv2 to XML via XSD validation enables and promotes the efficient
+ reuse of existing and future MIB modules and instrumentation by XML-
+ based protocols and management applications.
- Having such a standard mapping of SMIv2 to XML via XSD validation
- will enable and promote efficient reuse of existing (including
- future) MIB modules and instrumentation by XML-based management
- protocols and applications.
+ Developers of certain XML-based management applications will find
+ this specification sufficient for their purposes. Developers of
+ other XML-based management applications may need to make more
+ complete reuse of existing MIB modules, requiring standard XSD
+ documents for TCs [RFC2579] and MIB structure [RFC2578]. Memos
+ supporting such requirements are planned, but have not been produced
+ at the time of this writing.
- The goal of fidelity to the SMIv2 standard (STD58), as specified in
- the "Requirements" section below, is crucial to this effort to
- leverage the established "rough consensus" for the precise data
- modeling used in MIB modules, and to leverage existing "running code"
- for implemented SMIv2 data models. This effort does not include
- redesign of SMIv2 datatypes or data structures or textual conventions
- to overcome known limitations -- that work can be pursued in other
- efforts.
+ Finally, it is worthwhile to note that the goal of fidelity to the
+ SMIv2 standard (STD58), as specified in the "Requirements" section
+ below, is crucial to this effort. Fidelity leverages the established
+ "rough consensus" of the precise SMIv2 data models contained in MIB
+ modules, and leverages existing instrumentation, the "running code"
+ implementing SMIv2 data models. This effort does not include any
+ redesign of SMIv2 datatypes, data structures or textual conventions
+ in order to overcome known limitations. Such work can be pursued by
+ other efforts.
2. Conventions
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 RFC 2119 [RFC2119].
3. Requirements
The following set of requirements is intended to produce XML
documents which can be validated via the XSD defined in this
specification to faithfully represent values carried "on-the-wire" in
SNMP PDUs as defined by the SMI:
R1. All SMI base datatypes MUST have a corresponding XSD datatype.
- R2. SMIv2 is the normative SMI for this document -- SMIv1 modules,
- if encountered, MUST be converted (at least logically) in
- accordance with Section 2.1, inclusive, of the "Coexistence" RFC
- [RFC3584].
+ R2. SMIv2 is the normative SMI for this document. Prior to mapping
+ datatypes into XSD, legacy SMIv1 modules MUST be converted (at
+ least logically) in accordance with Section 2.1, inclusive, of
+ the "Coexistence" RFC [RFC3584].
R3. The XSD datatype specified for a given SMI datatype MUST be able
to represent all valid values for that SMI datatype.
R4. The XSD datatype specified for a given SMI datatype MUST
represent any special encoding rules associated with that SMI
datatype.
R5. The XSD datatype specified for a given SMI datatype MUST include
any restrictions on values associated with the SMI datatype.
R6. The XSD datatype specified for a given SMI datatype MUST be the
- most direct XSD datatype, with the most parsimonious
- restrictions, which matches the foregoing requirements.
+ most logical XSD datatype, with the fewest necessary
+ restrictions on its set of values, consistent with the foregoing
+ requirements.
R7. The XML output produced as a result of meeting the foregoing
- requirements SHOULD be the most direct (i.e., avoiding
- superfluous "decoration") from the perspective of readability by
- humans.
+ requirements SHOULD be the most coherent and succinct
+ representation (i.e., avoiding superfluous "decoration") from
+ the perspective of readability by humans.
4. XSD for SMI Base Datatypes
This document provides XSD datatype mappings for the SMIv2 base
datatypes only -- i.e., the eleven "ObjectSyntax" datatypes defined
in RFC 2578. These datatypes -- via tag values defined in the SMIv2
to identify them in varbinds -- constrain values carried "on-the-
wire" in SNMP PDUs between SNMP management applications and SNMP
agents:
@@ -222,28 +237,56 @@
xmlns="urn:ietf:params:xml:ns:opsawg:smi:base:1.0"
targetNamespace="urn:ietf:params:xml:ns:opsawg:smi:base:1.0"
elementFormDefault="qualified"
attributeFormDefault="unqualified"
xml:lang="en">
Mapping of SMIv2 base datatypes from RFC 2578
+ Contact: Mark Ellison
+ Organization: Ellison Software Consulting
+ Address: 38 Salem Road
+ Atkinson, NH 03811
+ USA
+ Telephone: +1 603-362-9270
+ E-Mail: ietf@EllisonSoftware.com
+
Contact: Bob Natale
Organization: MITRE
- Address: 7515 Colshire Drive
- McLean VA 22102
+ Address: 300 Sentinel Drive
+ 6th Floor
+ Annapolis Junction MD 20701
USA
- Telephone: +1 703-983-2505
+ Telephone: +1 301-617-3008
E-Mail: rnatale@mitre.org
- Last Updated: 200903090000Z
+
+ Last Updated: 201002260000Z
+
+ Copyright (c) 2010 IETF Trust and the persons
+ identified as the document authors. All rights
+ reserved.
+
+ Redistribution and use in source and binary forms,
+ with or without modification, is permitted pursuant
+ to, and subject to the license terms contained in,
+ the Simplified BSD License set forth in Section
+ 4.c of the IETF Trust's Legal Provisions Relating to
+ IETF Documents (http://trustee.ietf.org/license-info).
+
+ This version of this XML Schema Definition (XSD)
+ document is part of RFC XXXX; see the RFC itself for
+ full legal notices."
+ RFC Editor - please replace XXXX with the value allocated
+ for publication as an RFC.
+
@@ -301,21 +345,21 @@
END
5. Rationale
The XSD datatypes, including any specified restrictions, were chosen
based on fit with the requirements specified earlier in this
document, and with attention to simplicity while maintaining fidelity
to the SMI. Also, the "canonical representations" (i.e., refinements
of the "lexical representations") documented in the W3C XSD
- specifications are assumed.
+ specification [XMLSchema], [XSDDatatypes] are assumed.
5.1. Numeric Datatypes
All of the numeric XSD datatypes specified in the previous section --
INTEGER, Integer32, Unsigned32, Gauge32, Counter32, TimeTicks, and
Counter64 -- comply with the relevant requirements
o They cover all valid values for the corresponding SMI datatypes.
o They comply with the standard encoding rules associated with the
@@ -410,47 +454,48 @@
applications, not humans.
5.4. IpAddress
The XSD "string" datatype is the natural choice to represent an
IpAddress as XML output. The "pattern" restriction applied in this
case results in a dotted-decimal string of four values between "0"
and "255" separated by a period (".") character. This pattern also
precludes leading zeros.
+ Note that the SMI relies upon Textual Conventions (TCs) to specify an
+ IPv6 address. As such, the representation of an IPv6 address as an
+ XSD datatype is beyond the scope of this document.
+
5.5. ObjectIdentifier
This XSD datatype corresponds to the SMI "OBJECT IDENTIFIER"
datatype.
The XSD "string" datatype is also the natural choice to represent an
ObjectIdentifier as XML output, for the same reasons as for the
IpAddress choice. The "pattern" restriction applied in this case
results in a dotted-decimal string of up to 128 elements (referred to
as "sub-ids"), each holding an "Unsigned32" integer value.
- Note that, while not mentioned in Sec. 7.1.3 of RFC 2578, due to the
- use of Abstract Syntax Notation One (ASN.1) Basic Encoding Rules
- (BER) the first two components of an "OBJECT IDENTIFIER" have limited
- value ranges and are encoded into a single sub-id value [Steedman].
- The ASN.1/BER standards specify that the numerical value of the first
- sub-identifier is derived from the values of the first two "OBJECT
- IDENTIFIER" components in the value being encoded, using the formula:
- (X*40) + Y, where X is the value of the first component and Y is the
- value of the second component. This packing of the first two
- components recognizes that only three values are allocated from the
- root node, and at most 39 subsequent values from nodes reached by X =
- 0 and X = 1. The minimum length of an "OBJECT IDENTIFIER" is two
- sub-ids (with a zero-valued "OBJECT IDENTIFIER" represented as
- "0.0"). No explicit "minLength" restriction (which would be "3" to
- allow for the minimum of two sub-ids and a single separating dot) is
- required, since the pattern itself enforces this restriction.
+ Note that the first two components of an "OBJECT IDENTIFIER" each
+ have a limited range of values as indicated in the XSD pattern
+ restriction and as described in The ASN1.1/BER standard [ASN.1].
+
+ There are three values allocated for the root node, and at most 39
+ values for nodes subordinate to a root node value of 0 or 1.
+
+ The minimum length of an "OBJECT IDENTIFIER" is two sub-ids and the
+ representation of a zero-valued "OBJECT IDENTIFIER" is "0.0".
+
+ Note that no explicit "minLength" restriction, which would be "3" to
+ allow for the minimum of two sub-ids and a single separating dot, is
+ required since the pattern itself enforces this restriction.
6. Security Considerations
Security considerations for any given SMI MIB module are likely to be
relevant to any XSD/XML mapping of that MIB module; however, the
mapping defined in this document does not itself introduce any new
security considerations.
If and when proxies or gateways are developed to convey SNMP
management information from SNMP agents to XML-based management
@@ -500,24 +545,24 @@
of the research into existing approaches that was used as a baseline
for the recommendations in this particular specification.
This document owes much to draft-romascanu-netconf-datatypes-xx and
to many other sources (including libsmi and group discussions on the
NETCONF mailing lists) developed by those who have researched and
published candidate mappings of SMI datatypes to XSD.
Individuals who participated in various discussions of this topic at
IETF meetings and on IETF mailing lists include: Ray Atarashi,
- Yoshifumi Atarashi, Andy Bierman, Sharon Chisholm, Avri Doria, Mark
- Ellison, Rob Ennes, Mehmet Ersue, David Harrington, Alfred Hines,
- Eliot Lear, Chris Lonvick, Faye Ly, Randy Presuhn, Juergen
- Schoenwaelder, Andre Westerinen, and Bert Wijnen.
+ Yoshifumi Atarashi, Andy Bierman, Sharon Chisholm, Avri Doria, Rob
+ Ennes, Mehmet Ersue, David Harrington, Alfred Hines, Eliot Lear,
+ Chris Lonvick, Faye Ly, Randy Presuhn, Juergen Schoenwaelder, Andre
+ Westerinen, and Bert Wijnen.
9. References
9.1. Normative References
[RFC1155] Rose, M. and K. McCloghrie, "Structure and identification
of management information for TCP/IP-based internets",
STD 16, RFC 1155, May 1990.
[RFC2119] Bradner, s., "Key words for use in RFCs to Indicate
@@ -525,47 +570,59 @@
[RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
[RFC3584] Frye, R., Levi, D., Routhier, S., and B. Wijnen,
"Coexistence between Version 1, Version 2, and Version 3
of the Internet-standard Network Management Framework",
BCP 74, RFC 3584, August 2003.
-9.2. Informational References
-
- [RFC2579] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
- "Textual Conventions for SMIv2", STD 58, RFC 2579,
- April 1999.
-
- [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
- January 2004.
-
- [Steedman]
- Steedman, D., "ASN.1: The Tutorial and Reference".
-
[XML] World Wide Web Consortium, "Extensible Markup Language
(XML) 1.0", W3C XML, February 1998,
.
[XMLSchema]
World Wide Web Consortium, "XML Schema Part 1: Structures
Second Edition", W3C XML Schema, October 2004,
.
[XSDDatatypes]
World Wide Web Consortium, "XML Schema Part 2: Datatypes
Second Edition", W3C XML Schema, October 2004,
.
-Author's Address
+9.2. Informational References
+
+ [ASN.1] International Organization for Standardization,
+ "Information processing systems - Open Systems
+ Interconnection - Specification of Basic Encoding Rules
+ for Abstract Syntax Notation One (ASN.1)", International
+ Standard 8825, December 1987.
+
+ [RFC2579] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
+ "Textual Conventions for SMIv2", STD 58, RFC 2579,
+ April 1999.
+
+ [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
+ January 2004.
+
+Authors' Addresses
+
+ Mark Ellison
+ Ellison Software Consulting
+ 38 Salem Road
+ Atkinson, NH 03811
+ USA
+
+ Phone: +1 603-362-9270
+ Email: ietf@ellisonsoftware.com
Bob Natale
MITRE
- 7515 Colshire Dr
- MS H405
- McLean, VA 22102
+ 300 Sentinel Drive
+ 6th Floor
+ Annapolis Junction, MD 20701
USA
- Phone: +1 703-983-2505
+ Phone: +1 301-617-3008
Email: rnatale@mitre.org