NETCONF Working Group R. Tao
Internet-Draft B. Wu
Intended status: Standards Track Huawei
Expires: September 7, 2020 P. Liu
H. Cai
China Mobile
March 6, 2020

Self-explanation data Node tag capability
draft-tao-netconf-notif-node-tag-capabilities-01

Abstract

Before a client application subscribes to updates from a datastore, server capabilities related to "Subscription to YANG Datastores" can be advertised using YANG Instance Data format. These server capabilities can be documented at implement time or reported at run-time.

This document proposes a YANG module for self-explanation data Node tag capability which augments system capabilities model and provide additional self-explanation data node attributes associated with node selector within per-node capabilities.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

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."

This Internet-Draft will expire on September 7, 2020.

Copyright Notice

Copyright (c) 2020 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 (https://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 Simplified BSD License.


Table of Contents

1. Introduction

As described in [I-D.netconf-notification-capabilities], a server supporting YANG-Push MAY have a number of capabilities such as

Notification capability model defined in [I-D.netconf-notification-capabilities] allows a client to discover basic system capability and YANG-Push related capabilities both at implementation-time and run-time. Without using notification capability, it might lead to unexpected failure or additional message exchange for NETCONF clients to discover data models supported by a NETCONF server.

When the state of all subscriptions of a particular Subscriber to be fetched is huge, filtering queries of operational state on a server based on server capabilities can greatly reduce the amount of data to be streamed out to the destination.

However without self-explanation indication or instruction information associated with data node conveyed in Notification capability model [I-D.netconf-notification-capabilities] or pre-configured selection filter in the YANG Push model, it is hard for NETCONF clients to automatically select which data objects are of interest using machine to machine interface, e.g., identify a set of objects which have a common characteristic, collect specific object type nodes.

This document proposes a YANG module for self-explanation data Node tag capability which augments System Capabilities model and provide additional self-explanation data node tag attributes associated with node selector for queries filtering.

1.1. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

2. Self-explanation data Node tag capability

The YANG module ietf-notification-capabilities defined in [I-D.netconf-notification-capabilities] specify the following server capabilities related to YANG Push:

These server capabilities can be provided either at implementation time or reported at run time.

This document augments system capabilities model and provide additional data node self explaination attributes associated with node selector within per-node capabilities:

2.1. Tree Diagram

The following tree diagram [RFC8340] provides an overview of the data model.

    module: ietf-self-explanation-capabilities
    augment /sysc:system-capabilities/sysc:datastore-capabilities/ +
          sysc:per-node-capabilities/sys:node-selection/sys:node-selector:
       +--ro self-describing-attributes* [group-id]
           +--ro group-id                string
           +--ro opm-tag                 tags:tag
           +--ro measurement-precision   tags:tag
           +--ro measurement-scale       tags:tag
           +--ro operation-type          tags:tag
           +--ro service-tag*            tags:tag
           +--ro task-tag*               tags:tag
           +--ro data-source-type        tags:tag
           +--ro parent-grouping         tags:tag

3. YANG Module

<CODE BEGINS> file "ietf-self-explanation-capabilities.yang"
module ietf-self-explanation-capabilities {
  yang-version 1.1;
  namespace urn:ietf:params:xml:ns:yang:ietf-self-explanation-capabilities;
  prefix sec;
  import ietf-system-capabilities  { prefix sysc ; }
  import ietf-data-node-tags {prefix ntags;}
  import ietf-module-tags  { prefix tags; }
  organization
    "IETF NETMOD (Network Modeling) Working Group";
  contact
    "WG Web:   <https://tools.ietf.org/wg/netconf/>
     WG List:  <mailto:netconf@ietf.org>

     Editor:   Ran Tao
               <mailto:taoran20@huawei.com>
               Qin Wu
               <mailto:bill.wu@huawei.com";
  description
    "This module defines an extension to System Capabilities model 
     and provides additional self explaination data node tag attributes 
     associated with node selector for queries filtering.

     Copyright (c) 2020 IETF Trust and the persons identified as
     authors of the code.  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 YANG module is part of RFC XXXX;
     see the RFC itself for full legal notices.";
    augment "/sysc:system-capabilities/sysc:datastore-capabilities" +
         "/sysc:per-node-capabilities" +
          "/sysc:node-selection/sysc:node-selector" {
     description "Allows per-node capabilities have additional self-explanation attributes";
     list self-describing-attributes {
      key group-id;
      description "self describing attributes for each data node.";
       leaf group-id {
         type string;
         description
          "This group ID is used to identify a set of data nodes
          of the same group which have a common characteristic.";
       }
         leaf opm-tag {
           type tags:tag ;
           description
            "Object, Property and Metric(OPM) Tags associated with 
            the data node within YANG module.
            See the IANA 'YANG Data Node Tag Prefixes' registry
            for reserved prefixes and the IANA
            'IETF YANG Data Node Tags' registry for IETF tags.";
       }
         leaf measurement-precision {
           type tags:tag;
           description
             "The numeric expression precision of performance
              metric related data node.";
         }

        leaf measurement-scale {
            type tags:tag;
            description
             "The measurement scale of performance
              metric related data node.";
         }
         leaf operation-type{
          type tags:tag;
          description
           "Statistics operation of performance metric related
           data node.";
         }
         leaf-list service-tag {
          type tags:tag;
          description
           "The node-service-tag can be used to provide a service
           classification information (e.g., tunnel, l3vpn,l2vpn)
           information associated with YANG data node.";
         }
         leaf-list task-tag {
          type tags:tag;
          description
           "The node-task-tag can be used to provide a task
           classification information (e.g., fault management,
           performance measurement) information associated with
           YANG data node.";
         }
         leaf data-source-type{
          type tags:tag;
          description
           "The data source type can be used to identify different
            data source type(e.g., service flow, resource, policy,
            qos, hardware).";
         }
         leaf parent-grouping{
          type tags:tag;
          description
           "The parent grouping tag can be used to aggregate peformance metric
            from different sources.";
         }
     }
   }
}
<CODE ENDS>

4. IANA Considerations

4.1. Updates to the IETF XML Registry

This document registers a URI in the "IETF XML Registry" [RFC3688]. Following the format in [RFC3688], the following registration has been made:

   URI:
      urn:ietf:params:xml:ns:yang:ietf-self-explanation-capabilities
   Registrant Contact:
      The IESG.
   XML:
      N/A; the requested URI is an XML namespace.

4.2. Updates to the YANG Module Names Registry

This document registers one YANG module in the "YANG Module Names" registry [RFC6020]. Following the format in [RFC6020], the following registration has been made:

   name:
      ietf-self-explanation-capabilities
   namespace:
      urn:ietf:params:xml:ns:yang:ietf-self-explanation-capabilities
   prefix:
      sec
   reference:
      RFC XXXX (RFC Ed.: replace XXX with actual RFC number and remove
      this note.)

5. Security Considerations

The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].

The NETCONF Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.

There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:

6. References

6.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011.
[RFC7950] Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016.
[RFC8040] Bierman, A., Bjorklund, M. and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017.
[RFC8126] Cotton, M., Leiba, B. and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K. and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018.
[RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", BCP 216, RFC 8407, DOI 10.17487/RFC8407, October 2018.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018.

6.2. Informative References

[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010.
[RFC8340] Bjorklund, M. and L. Berger, "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018.

Authors' Addresses

Ran Tao Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China EMail: taoran20@huawei.com
Bo Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China EMail: lana.wubo@huawei.com
Peng Liu China Mobile 32 Xuanwumen West St, Xicheng District Beijing, 10053 EMail: liupengyjy@chinamobile.com
Hui Cai China Mobile 32 Xuanwumen West St, Xicheng District Beijing, 10053 EMail: caihui@chinamobile.com