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Versions: (draft-hopps-lsr-yang-isis-reverse-metric) 00 01

Network Working Group                                           C. Hopps
Internet-Draft                                   LabN Consulting, L.L.C.
Intended status: Standards Track                            28 July 2020
Expires: 29 January 2021


                  YANG Module for IS-IS Reverse Metric
               draft-ietf-lsr-yang-isis-reverse-metric-01

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 29 January 2021.

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.






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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  YANG Management . . . . . . . . . . . . . . . . . . . . . . .   2
     2.1.  YANG Tree . . . . . . . . . . . . . . . . . . . . . . . .   2
     2.2.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     3.1.  Updates to the IETF XML Registry  . . . . . . . . . . . .   7
     3.2.  Updates to the YANG Module Names Registry . . . . . . . .   8
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .  10
   6.  Informative References  . . . . . . . . . . . . . . . . . . .  11
   Appendix A.  Examples . . . . . . . . . . . . . . . . . . . . . .  11
     A.1.  Example Enable XML  . . . . . . . . . . . . . . . . . . .  11
     A.2.  Example Use XML . . . . . . . . . . . . . . . . . . . . .  12
     A.3.  Example JSON  . . . . . . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  14

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.
















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   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].  It imports modules from
   the following RFCs: [RFC8349], [I-D.ietf-isis-yang-isis-cfg].







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   <CODE BEGINS> file "ietf-isis-reverse-metric@2020-07-28.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;
       reference
         "RFC8349: A YANG Data Model for Routing Management (NMDA Version)";
     }
     import ietf-isis {
       prefix isis;
       reference
         "draft-ietf-isis-yang-isis-cfg-42:
          YANG Data Model for IS-IS Protocol";
     }

     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.";



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     revision 2020-07-28 {
       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.";
         reference "RFC8500, Section 2";
       }

       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.";
           reference "RFC8500, Section 2";
         }
         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.";
           reference "RFC8500, Section 2";
         }
       }
     }

     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



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              reverse metric TLV.";
           reference "RFC8500, Section 3.5";
         }
       }
     }

     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.";
           reference "RFC8500, Section 3.5";
         }
       }
     }

     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'" {



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         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




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   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 NETCONF access control model [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.

   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 or vulnerable
   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:



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   Under "/rt:routing/rt:control-plane-protocols/" +
         "rt:control-plane-protocol/isis:isis"

     - /isis-rmetric:reverse-metric/isis-rmetric:enable-receive

   Under "/rt:routing/rt:control-plane-protocols/" +
         "rt:control-plane-protocol/isis:isis/" +
         "isis:interfaces/isis:interface/" +
         "isis-rmetric:reverse-metric"

     - /isis-rmetric:metric
     - /isis-rmetric:flags/isis-rmetric:whole-lan
     - /isis-rmetric:flags/isis-rmetric:allow-unreachable
     - /isis-rmetric:exclude-te-metric

   Under "/rt:routing/rt:control-plane-protocols/" +
         "rt:control-plane-protocol/isis:isis/" +
         "isis:interfaces/isis:interface/" +
         "isis:level-1/isis-rmetric:reverse-metric"

     - /isis-rmetric:metric
     - /isis-rmetric:flags/isis-rmetric:whole-lan
     - /isis-rmetric:flags/isis-rmetric:allow-unreachable
     - /isis-rmetric:exclude-te-metric

   Under "/rt:routing/rt:control-plane-protocols/" +
         "rt:control-plane-protocol/isis:isis/" +
         "isis:interfaces/isis:interface/" +
         "isis:level-2/isis-rmetric:reverse-metric"

     - /isis-rmetric:metric
     - /isis-rmetric:flags/isis-rmetric:whole-lan
     - /isis-rmetric:flags/isis-rmetric:allow-unreachable
     - /isis-rmetric:exclude-te-metric

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

   All nodes are under the following subtree, so that prefix will be
   assume for each node description.








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   Under "/rt:routing/rt:control-plane-protocols/" +
         "rt:control-plane-protocol/isis:isis/" +
         "isis:interfaces/isis:interface/" +
         "isis:adjacencies/isis:adjacency/" +
         "isis-rmetric:reverse-metric"

       - /isis-rmetric:metric
       - /isis-rmetric:flags/isis-rmetric:whole-lan
       - /isis-rmetric:flags/isis-rmetric:allow-unreachable
       - /isis-rmetric:te-metric

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, 1992.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <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, October 2010,
              <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, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <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, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.





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   [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,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8349]  Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
              Routing Management (NMDA Version)", RFC 8349,
              DOI 10.17487/RFC8349, March 2018,
              <https://www.rfc-editor.org/info/rfc8349>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <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,
              February 2019, <https://www.rfc-editor.org/info/rfc8500>.

   [I-D.ietf-isis-yang-isis-cfg]
              Litkowski, S., Yeung, D., Lindem, A., Zhang, Z., and L.
              Lhotka, "YANG Data Model for IS-IS Protocol", Work in
              Progress, Internet-Draft, draft-ietf-isis-yang-isis-cfg-
              42, 15 October 2019, <https://tools.ietf.org/html/draft-
              ietf-isis-yang-isis-cfg-42>.

6.  Informative References

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <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.














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   <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.



























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   <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.










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   {
     "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.




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   Email: chopps@chopps.org


















































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