--- 1/draft-ietf-netmod-yang-usage-01.txt 2009-10-26 20:12:23.000000000 +0100 +++ 2/draft-ietf-netmod-yang-usage-02.txt 2009-10-26 20:12:23.000000000 +0100 @@ -1,18 +1,18 @@ Internet Engineering Task Force A. Bierman -Internet-Draft Netconf Central -Intended status: Informational August 12, 2009 -Expires: February 13, 2010 +Internet-Draft Netconf Central, Inc. +Intended status: Informational October 26, 2009 +Expires: April 29, 2010 Guidelines for Authors and Reviewers of YANG Data Model Documents - draft-ietf-netmod-yang-usage-01 + draft-ietf-netmod-yang-usage-02 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. @@ -21,21 +21,21 @@ 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 February 13, 2010. + This Internet-Draft will expire on April 29, 2010. Copyright Notice Copyright (c) 2009 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 @@ -58,21 +58,21 @@ 2.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . . . 5 2.3. YANG Terms . . . . . . . . . . . . . . . . . . . . . . . . 5 2.4. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. General Documentation Guidelines . . . . . . . . . . . . . . . 7 3.1. YANG Data Model Boilerplate Section . . . . . . . . . . . 7 3.2. Narrative Sections . . . . . . . . . . . . . . . . . . . . 7 3.3. Definitions Section . . . . . . . . . . . . . . . . . . . 8 3.4. Security Considerations Section . . . . . . . . . . . . . 8 3.5. IANA Considerations Section . . . . . . . . . . . . . . . 8 3.5.1. Documents that Create a New Name Space . . . . . . . . 8 - 3.5.2. Documents that Extend an Existing Name Space . . . . . 8 + 3.5.2. Documents that Extend an Existing Name Space . . . . . 9 3.6. Reference Sections . . . . . . . . . . . . . . . . . . . . 9 3.7. Copyright Notices . . . . . . . . . . . . . . . . . . . . 9 3.8. Intellectual Property Section . . . . . . . . . . . . . . 9 4. YANG Usage Guidelines . . . . . . . . . . . . . . . . . . . . 10 4.1. Module Naming Conventions . . . . . . . . . . . . . . . . 10 4.2. Identifiers . . . . . . . . . . . . . . . . . . . . . . . 10 4.3. Defaults . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.4. Conditional Statements . . . . . . . . . . . . . . . . . . 11 4.5. Lifecycle Management . . . . . . . . . . . . . . . . . . . 12 4.6. Header Contents . . . . . . . . . . . . . . . . . . . . . 12 @@ -86,20 +86,21 @@ 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 6. Security Considerations . . . . . . . . . . . . . . . . . . . 19 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 8.1. Normative References . . . . . . . . . . . . . . . . . . . 21 8.2. Informative References . . . . . . . . . . . . . . . . . . 21 Appendix A. Module Review Checklist . . . . . . . . . . . . . . . 22 Appendix B. YANG Module Template . . . . . . . . . . . . . . . . 24 Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 27 C.1. Changes from 00 to 01 . . . . . . . . . . . . . . . . . . 27 + C.2. Changes from 01 to 02 . . . . . . . . . . . . . . . . . . 27 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 28 1. Introduction The standardization of network configuration interfaces for use with the NETCONF [RFC4741] protocol requires a modular set of data models, which can be reused and extended over time. This document defines a set of usage guidelines for standards track documents containing YANG [I-D.ietf-netmod-yang] data models. It is @@ -118,27 +119,27 @@ Layer Example +-------------+ +--------------------+ +-------------------+ (4) | Content | | Configuration data | | Notification data | +-------------+ +--------------------+ +-------------------+ | | | +-------------+ +-----------------+ +---------------+ (3) | Operations | | | | | +-------------+ +-----------------+ +---------------+ | | | +-------------+ +--------------------+ +----------------+ - (2) | RPC | | , | | | + (2) | Messages | | , | | | +-------------+ +--------------------+ +----------------+ | | | - +-------------+ +--------------------------------+ - (1) | Transport | | BEEP, SSH, SSL, TLS, console | - | Protocol | | | - +-------------+ +--------------------------------+ + +-------------+ +-----------------------------------------------+ + (1) | Secure | | SSH, TLS, BEEP/TLS, SOAP/BEEP, SOAP/HTTPS ... | + | Transports | | | + +-------------+ +-----------------------------------------------+ Figure 1 This document defines usage guidelines related to the NETCONF operations layer (3), and NETCONF content layer (4). 2. Terminology 2.1. Requirements Notation @@ -149,32 +150,32 @@ RFC 2119 language is used here to express the views of the NETMOD working group regarding YANG module content. Yang modules complying with this document will treat the RFC 2119 terminology as if it were describing best current practices. 2.2. NETCONF Terms The following terms are defined in [RFC4741] and are not redefined here: - o agent - o application o capabilities - o manager + o client o operation o RPC + o server + 2.3. YANG Terms The following terms are defined in [I-D.ietf-netmod-yang] and are not redefined here: o data node o module o submodule @@ -217,21 +217,26 @@ o Security Considerations section o IANA Considerations section o References section 3.1. YANG Data Model Boilerplate Section This section MUST contain a verbatim copy of the latest approved Internet-Standard Management Framework boilerplate, which is - available on-line at [ed: URL TBD]. + available on-line, in section 4 of the Trust Legal Provisions (TLP) + document, at: http://trustee.ietf.org/license-info/ + + Each YANG module contained within an Internet Draft or RPC MUST be + identified as a 'Code Component'. The strings '' and + '' SHOULD be used to identify each Code Component. 3.2. Narrative Sections The narrative part MUST include an overview section that describes the scope and field of application of the module(s) defined by the specification and that specifies the relationship (if any) of these modules to other standards, particularly to standards containing other module modules. The narrative part SHOULD include one or more sections to briefly describe the structure of the modules defined in the specification. @@ -294,46 +299,45 @@ is to be administered. Specifically, if any YANG submodule belongs-to value contained in the document is associated with a module that contains a namespace statement value equal to a YANG Namespace already administered by the IANA, then the existing YANG Namespace must be updated to include the new submodule. 3.6. Reference Sections - [ed: 2223bis text TBD] - For every import or include statement which appears in a module contained in the specification, which identifies a module in a separate document, a corresponding normative reference to that document MUST appear in the Normative References section. The reference MUST correspond to the specific module version actually used within the specification. For every reference statement which appears in a module contained in the specification, which identifies a separate document, a corresponding normative reference to that document SHOULD appear in the Normative References section. The reference SHOULD correspond to the specific document version actually used within the specification. 3.7. Copyright Notices The proper copyright notices MUST be present in the module - description statement. [ed.: See RFC 4181, 3.7. Exact text for - insertion is TBD.] + description statement. Refer to the IETF Trust Legal Provision for + the exact legal text that needs to be included. 3.8. Intellectual Property Section The proper IPR statements MUST be present in the document, according - to the most current Internet Draft boilerplate. [ed.: actual IETF IPR - text reference TBD] + to the most current Internet Draft boilerplate. Refer to the IETF + Trust Legal Provision for the exact legal text that needs to be + included. 4. YANG Usage Guidelines In general, modules in IETF standards-track specifications MUST comply with all syntactic and semantic requirements of YANG. [I-D.ietf-netmod-yang]. The guidelines in this section are intended to supplement the YANG specification, which is intended to define a minimum set of conformance requirements. In order to promote interoperability and establish a set of practices @@ -395,32 +399,32 @@ an 'if-feature' statement SHOULD be used instead of a 'when' statement. All 'must' and 'when' statements MUST contain valid XPath. If any name tests are present, they MUST contain valid module prefixes and data node names. References to non-existent nodes are considered invalid in YANG, even though they are permitted in XPath. The 'attribute' and 'namespace' axis SHOULD NOT be used because the associated XML node types are not supported in YANG, and may not be - supported consistently across NETCONF agent implementations. + supported consistently across NETCONF server implementations. The 'position' and 'last' functions SHOULD NOT be used. Also, the 'preceding', and 'following' axes SHOULD NOT be used. These - constructs rely on XML document order within a NETCONF agent + constructs rely on XML document order within a NETCONF server configuration database, which may not be supported consistently or produce reliable results across implementations. Predicate expressions based on static node properties (e.g., name, value, ancestors, descendants) SHOULD be used instead. The 'preceding-sibling' and 'following-sibling' axes MAY be used, - with caution. An agent is not required to maintain a persistent or + with caution. A server is not required to maintain a persistent or deterministic XML document order, which will affect use of these axes. Implicit 'position' function calls within predicates SHOULD NOT be used. (e.g., //chapter[42]). Data nodes which use the 'int64' and 'uint64' built-in type SHOULD NOT be used within relational expressions. There are boundary conditions in which the translation from the YANG 64-bit type to an XPath number can cause incorrect results. @@ -453,21 +457,22 @@ present. It SHOULD be present (in all published modules) if any groupings are used from the external sub-module. 4.6. Header Contents For published modules, the namespace MUST be a globally unique URI, as defined in [RFC3986]. This value is usually assigned by the IANA. The organization statement MUST be present. If the module is contained in a documented intended for standards-track status, then - the organization SHOULD be the IETF. + the organization SHOULD be the IETF working group chartered to write + the document. The contact statement MUST be present. If the module is contained in a documented intended for standards-track status, then the working group WEB and mailing information MUST be present, and the document author contact information SHOULD be present. In addition, the Area Director and other contact information MAY be present. The description statement MUST be present. If the module is contained in an unpublished document, then the file name of this document SHOULD be identified in the description statement. This @@ -546,28 +551,28 @@ module. However, there MAY be more than one if needed. The top-level data organization SHOULD be considered carefully, in advance. Data model designers need to consider how the functionality for a given protocol or protocol family will grow over time. The names and data organization SHOULD reflect persistent information, such as the name of a protocol. The name of the working group SHOULD NOT be used because this may change over time. - A mandatory database object is defined as a node that a manager must - provide for the database to be valid. The agent will not provide a + A mandatory database object is defined as a node that a client must + provide for the database to be valid. The server will not provide a value under any conditions. Top-level database objects MUST NOT be mandatory. If a mandatory node appears at the top-level, it will immediately - cause the database to be invalid. This can occur when the agent + cause the database to be invalid. This can occur when the server boots or when a module is loaded dynamically at runtime. Top level objects are declared in YANG as mandatory with the mandatory statement or the min-elements statement. All nested non- presence containers are transparent, so a mandatory node nested within one or more non-presence containers causes the top-level container to be considered mandatory. 4.9. Data Types @@ -581,22 +586,21 @@ If extensibility of enumerated values is required, then the identityref data type SHOULD be used instead of an enumeration or other built-in type. For string data types, if a machine-readable pattern can be defined for the desired semantics, then one or more pattern statements SHOULD be present. For string data types, if the length of the string is not required to be unbounded in all implementations, then a length statement SHOULD - be present. [ed: should the 'resource-denied' error be mentioned - here?] + be present. For numeric data types, if the values allowed by the intended semantics are different than those allowed by the unbounded intrinsic data type (e.g., int32), then a range statement SHOULD be present. The signed numeric data types (i.e., 'int8', 'int16', 'int32', and 'int64') SHOULD NOT be used unless negative values are allowed for the desired semantics. For enumeration or bits data types, the semantics for each enum or @@ -700,22 +704,21 @@ then a reference statement SHOULD be present. 5. IANA Considerations There are no actions requested of IANA at this time. 6. Security Considerations This document defines documentation guidelines for NETCONF content defined with the YANG data modeling language. It does not introduce - any new or increased security risks into the management system. [ed: - RFC 4181 style security section TBD] + any new or increased security risks into the management system. 7. Acknowledgments The structure and contents of this document are adapted from Guidelines for MIB Documents [RFC4181], by C. M. Heard. 8. References 8.1. Normative References @@ -724,27 +727,27 @@ [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC4741] Enns, R., "NETCONF Configuration Protocol", RFC 4741, December 2006. [I-D.ietf-netmod-yang] Bjorklund, M., "YANG - A data modeling language for - NETCONF", draft-ietf-netmod-yang-07 (work in progress), - July 2009. + NETCONF", draft-ietf-netmod-yang-08 (work in progress), + October 2009. [I-D.ietf-netmod-yang-types] Schoenwaelder, J., "Common YANG Data Types", - draft-ietf-netmod-yang-types-03 (work in progress), - May 2009. + draft-ietf-netmod-yang-types-04 (work in progress), + October 2009. 8.2. Informative References [RFC4181] Heard, C., "Guidelines for Authors and Reviewers of MIB Documents", BCP 111, RFC 4181, September 2005. Appendix A. Module Review Checklist This section is adapted from RFC 4181. @@ -819,37 +822,38 @@ errors; see [YANG tool URL TBD] for more information. Checking for correct syntax, however, is only part of the job. It is just as important to actually read the YANG module document from the point of view of a potential implementor. It is particularly important to check that description statements are sufficiently clear and unambiguous to allow interoperable implementations to be created. Appendix B. YANG Module Template -== begin "ietf-template.yang" + module ietf-template { // replace this string with a unique namespace URN value namespace - "urn:ietf:params:xml:ns:yang:ietf-template:DRAFT-01"; + "urn:ietf:params:xml:ns:yang:ietf-template:DRAFT-02"; // replace this string, and try to pick a unique prefix prefix "temp"; // import statements here: e.g., // import ietf-yang-types { prefix yang; } // import ietf-inet-types { prefix inet; } + // identify the IETF working group if applicable organization - "Internet Engineering Task Force"; + "IETF NETMOD (NETCONF Data Modeling Language) Working Group"; // update this contact statement with your info contact "WG Web: WG List: WG Chair: your-WG-chair Editor: your-name @@ -899,27 +903,28 @@ POSSIBILITY OF SUCH DAMAGE. This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; // RFC Ed.: replace XXXX with actual RFC number and remove this note reference "RFC XXXX"; // RFC Ed.: remove this note - // Note: extracted from draft-ietf-netmod-yang-usage-01.txt + // Note: extracted from draft-ietf-netmod-yang-usage-02.txt // replace YYYY-MM-DD with a real date (year-month-day) // here is an example revision date: 2009-08-12 revision YYYY-MM-DD { description "Initial version"; + } // extension statements // feature statements // identity statements // typedef statements @@ -930,21 +935,21 @@ // augment statements // rpc statements // notification statements // DO NOT put deviation statements in a published module } -== end "ietf-template.yang" + Figure 2 Appendix C. Change Log C.1. Changes from 00 to 01 o Added transport 'TLS' to figure 1. o Added note about RFC 2119 terminology. @@ -958,18 +963,36 @@ o Added note on use of preceding-sibling and following-sibling axes in XPath expressions. o Added section on temporary namespace statement values. o Added section on top level database objects. o Added ietf-template.yang appendix. +C.2. Changes from 01 to 02 + + o Updated figure 1 per mailing list comments. + + o Updated suggested organization to include the working group name. + + o Updated ietf-template.yang to use new organization statement + value. + + o Updated Code Component requirements as per new TLP. + + o Updated ietf-template.yang to use new Code Component begin and end + markers. + + o Updated references to the TLP in a couple sections. + + o Change manager/agent terminology to client/server. + Author's Address Andy Bierman - Netconf Central + Netconf Central, Inc. Simi Valley, CA USA Email: andy@netconfcentral.com