Internet-Draft YANG Module for IS-IS Reverse Metric January 2020
Hopps Expires 25 July 2020 [Page]
Workgroup:
Network Working Group
Published:
Intended Status:
Standards Track
Expires:
Author:
C. Hopps
LabN Consulting, L.L.C.

YANG Module for IS-IS Reverse Metric

Abstract

This document defines a YANG module for managing the reverse metric extension to the the intermediate system to intermediate system routeing protocol.

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 25 July 2020.

1. Introduction

This document defines a YANG module for managing the reverse metric extension to the intermediate system to intermediate system routeing protocol (IS-IS) [RFC8500], [ISO10589]. Please refer to [RFC8500] for the description and definition of the functionality managed by this module.

The YANG data model described in this document conforms to the Network Management Datastore Architecture defined in [RFC8342].

2. YANG Management

2.1. YANG Tree

The following is the YANG tree diagram ([RFC8340]) for the IS-IS reverse metric extension additions.


module: ietf-isis-reverse-metric
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/isis:isis:
    +--rw reverse-metric
       +--rw enable-receive?   boolean
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/isis:isis/isis:interfaces
            /isis:interface:
    +--rw reverse-metric
       +--rw reverse-metric
       |  +--rw metric?              isis:wide-metric
       |  +--rw flags
       |  |  +--rw whole-lan?           boolean
       |  |  +--rw allow-unreachable?   boolean
       |  +--rw exclude-te-metric?   boolean
       +--rw level-1
       |  +--rw reverse-metric
       |     +--rw metric?              isis:wide-metric
       |     +--rw flags
       |     |  +--rw whole-lan?           boolean
       |     |  +--rw allow-unreachable?   boolean
       |     +--rw exclude-te-metric?   boolean
       +--rw level-2
          +--rw reverse-metric
             +--rw metric?              isis:wide-metric
             +--rw flags
             |  +--rw whole-lan?           boolean
             |  +--rw allow-unreachable?   boolean
             +--rw exclude-te-metric?   boolean
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/isis:isis/isis:interfaces
            /isis:interface/isis:adjacencies/isis:adjacency:
    +--ro reverse-metric
       +--ro metric?      isis:wide-metric
       +--ro flags
       |  +--ro whole-lan?           boolean
       |  +--ro allow-unreachable?   boolean
       +--ro te-metric?   uint32

2.2. YANG Module

The following is the YANG module for managing the IS-IS reverse metric functionality defined in [RFC8500].

<CODE BEGINS> file "ietf-isis-reverse-metric@2020-01-22.yang"
module ietf-isis-reverse-metric {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-isis-reverse-metric";
  prefix isis-rmetric;

  import ietf-routing { prefix "rt"; }
  import ietf-isis { prefix "isis"; }

  organization
    "IETF LSR Working Group (LSR)";

  contact
    "WG Web:  <https://tools.ietf.org/wg/lsr/>
     WG List: <mailto:lsr@ietf.org>

     Author: Christian Hopps
             <mailto:chopps@chopps.org>";

  // RFC Ed.: replace XXXX with actual RFC number and
  // remove this note.

  description
    "This module defines the configuration and operational state for
     managing the IS-IS reverse metric functionality [RFC8500].

     Copyright (c) 2019 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
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX
     (https://tools.ietf.org/html/rfcXXXX); see the RFC itself for
     full legal notices.";

  revision 2020-01-22 {
    description "Initial Revision";
    reference "RFC XXXX: YANG IS-IS Reverse Metric";
  }

  grouping reverse-metric-data {
    description "IS-IS reverse metric data.";
    leaf metric {
      type isis:wide-metric;
      description "The reverse metric value.";
    }

    container flags {
      description "The reverse metric flag values.";
      leaf whole-lan {
        type boolean;
        description
            "The 'whole LAN' or W-bit. If true then a DIS processing this
            reverse metric will add the metric value to all the nodes it
            advertises in the pseudo-node LSP for this interface.
            Otherwise it will only increment the metric for the
            advertising node in the pseudo-node LSP for this interface.";
      }
      leaf allow-unreachable {
        type boolean;
        description
            "The 'allow-unreachable' or U-bit. If true it allows the
            neighbor to increment the overall metric up to 2^24-1 rather
            than the lesser maximum of 2^24-2, and if done will cause
            traffic to stop using rather than avoid using the interface.";
      }
    }
  }

  grouping reverse-metric-if-config-data {
    description "IS-IS reverse metric config data.";
    container reverse-metric {
      description "IS-IS reverse metric data.";
      uses reverse-metric-data;
      leaf exclude-te-metric {
        type boolean;
        default false;
        description
          "If true and there is a TE metric defined for this
           interface then do not send the TE metric sub-TLV in the
           reverse metric TLV.";
      }
    }
  }

  grouping tlv16-reverse-metric {
    description "IS-IS reverse metric TLV data.";
    container reverse-metric {
      description "IS-IS reverse metric TLV data.";
      uses reverse-metric-data;
      leaf te-metric {
        type uint32;
        description "The TE metric value from the sub-TLV if present.";
      }
    }
  }

  augment "/rt:routing/rt:control-plane-protocols/"
    +"rt:control-plane-protocol/"
    +"isis:isis" {
    when "../rt:type = 'isis:isis'" {
      description
        "This augment is only valid when routing protocol instance
         type is 'isis'.";
    }

    description
      "The reverse metric configuration for an IS-IS instance.";

    container reverse-metric {
      description "Global reverse metric configuration.";
      leaf enable-receive {
        type boolean;
        default false;
        description
          "Enable handling of reverse metric announcements from
           neighbors. By default reverse metric handling is disabled
           and must be explicitly enabled through this configuration.";
      }
    }
  }

  augment "/rt:routing/rt:control-plane-protocols/"
    +"rt:control-plane-protocol/"
    +"isis:isis/isis:interfaces/isis:interface" {
    when "../../../rt:type = 'isis:isis'" {
      description
        "This augment is only valid when routing protocol instance
         type is 'isis'.";
    }

    description
      "The reverse metric configuration for an interface.";

    container reverse-metric {
      description "Announce a reverse metric to neighbors.";
      uses reverse-metric-if-config-data;
      container level-1 {
        description "Announce a reverse metric to level-1 neighbors.";
        uses reverse-metric-if-config-data;
      }
      container level-2 {
        description "Announce a reverse metric to level-2 neighbors.";
        uses reverse-metric-if-config-data;
      }
    }
  }
  augment "/rt:routing/rt:control-plane-protocols/"
    +"rt:control-plane-protocol/"
    +"isis:isis/isis:interfaces/isis:interface/"
    +"isis:adjacencies/isis:adjacency" {
    when "../../../../../rt:type = 'isis:isis'" {
      description
        "This augment is only valid when routing protocol instance
         type is 'isis'";
    }

    description
      "The reverse metric state advertised by an adjacency.";
    uses tlv16-reverse-metric;
  }
}
<CODE ENDS>

3. IANA Considerations

3.1. 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-isis-reverse-metric

Registrant Contact

The IESG.

XML

N/A; the requested URI is an XML namespace.

3.2. 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-isis-reverse-metric

namespace

urn:ietf:params:xml:ns:yang:ietf-isis-reverse-metric

prefix

isis-rmetric

reference

RFC XXXX (RFC Ed.: replace XXX with actual RFC number and remove this note.)

4. 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 Network 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.

The YANG module defined in this document can enable, disable and modify the behavior of metrics used by routing. For the security implications regarding these types of changes consult the [RFC8500] which defines the functionality.

5. Normative References

[ISO10589]
International Organization for Standardization, "Intermediate system to intermediate system intra-domain-routing routine information exchange protocol for use in conjunction with the protocol for providing the connectionless-mode Network Service (ISO 8473)", ISO Standard 10589, .
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/info/rfc3688>.
[RFC6020]
Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <https://www.rfc-editor.org/info/rfc6020>.
[RFC6241]
Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
[RFC8341]
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <https://www.rfc-editor.org/info/rfc8341>.
[RFC8342]
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/info/rfc8342>.
[RFC8446]
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <https://www.rfc-editor.org/info/rfc8446>.
[RFC8500]
Shen, N., Amante, S., and M. Abrahamsson, "IS-IS Routing with Reverse Metric", RFC 8500, DOI 10.17487/RFC8500, , <https://www.rfc-editor.org/info/rfc8500>.

6. Informative References

[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/info/rfc8340>.

Appendix A. Examples

A.1. Example Enable XML

Below is an example of YANG XML data to enable reverse metric processing.

<rt:routing
    xmlns:rt="urn:ietf:params:xml:ns:yang:ietf-routing"
    xmlns:isis="urn:ietf:params:xml:ns:yang:ietf-isis"
    xmlns:rm="urn:ietf:params:xml:ns:yang:ietf-isis-reverse-metric">
  <rt:control-plane-protocols>
    <rt:control-plane-protocol>
      <rt:type>isis:isis</rt:type>
      <rt:name>default</rt:name>
      <isis:isis>
        <isis:area-address>00</isis:area-address>
        <rm:reverse-metric>
          <rm:enable-receive>true</rm:enable-receive>
        </rm:reverse-metric>
      </isis:isis>
    </rt:control-plane-protocol>
  </rt:control-plane-protocols>
</rt:routing>
Figure 1: Example XML data to enable reverse metric processing.

A.2. Example Use XML

Below is an example of YANG XML data for the ietf-isis-reverse-metric module.

<if:interfaces
    xmlns:if="urn:ietf:params:xml:ns:yang:ietf-interfaces"
    xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
  <if:interface>
    <if:name>eth0</if:name>
    <if:type>ianaift:ethernetCsmacd</if:type>
  </if:interface>
</if:interfaces>
<rt:routing
    xmlns:rt="urn:ietf:params:xml:ns:yang:ietf-routing"
    xmlns:isis="urn:ietf:params:xml:ns:yang:ietf-isis"
    xmlns:rm="urn:ietf:params:xml:ns:yang:ietf-isis-reverse-metric">
  <rt:control-plane-protocols>
    <rt:control-plane-protocol>
      <rt:type>isis:isis</rt:type>
      <rt:name>default</rt:name>
      <isis:isis>
        <isis:area-address>00</isis:area-address>
        <isis:interfaces>
          <isis:interface>
            <isis:name>eth0</isis:name>
            <rm:reverse-metric>
              <rm:reverse-metric>
                <rm:metric>
                  65535
                </rm:metric>
              </rm:reverse-metric>
            </rm:reverse-metric>
          </isis:interface>
        </isis:interfaces>
      </isis:isis>
    </rt:control-plane-protocol>
  </rt:control-plane-protocols>
</rt:routing>
Figure 2: Example XML data for ietf-isis-reverse-metric module.

A.3. Example JSON

Below is an example of YANG XML data for the ietf-isis-reverse-metric module.

{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "eth0",
        "type": "iana-if-type:ethernetCsmacd"
      }
    ]
  },
  "ietf-routing:routing": {
    "control-plane-protocols": {
      "control-plane-protocol": [
        {
          "type": "ietf-isis:isis",
          "name": "default",
          "ietf-isis:isis": {
            "area-address": [
              "00"
            ],
            "interfaces": {
              "interface": [
                {
                  "name": "eth0",
                  "ietf-isis-reverse-metric:reverse-metric": {
                    "level-1": {
                      "reverse-metric": {
                        "metric": 65535,
                        "exclude-te-metric": true
                      }
                    }
                  }
                }
              ]
            }
          }
        }
      ]
    }
  }
}
Figure 3: Example JSON data for level-1 only reverse metric.

Author's Address

Christian Hopps
LabN Consulting, L.L.C.