Internet-Draft MPLS MSD YANG June 2024
Qu, et al. Expires 6 December 2024 [Page]
Workgroup:
MPLS Working Group
Internet-Draft:
draft-ietf-mpls-msd-yang-08
Published:
Intended Status:
Standards Track
Expires:
Authors:
Y. Qu
Futurewei Technologies
A. Lindem
LabN Consulting, L.L.C.
S. Litkowski
Cisco Systems
J. Tantsura
Nvidia

YANG Data Model for MPLS Maximum Segment Identifier (SID) Depth (MSD)

Abstract

This document defines two YANG data modules. The first is the initial version of the IANA-maintained YANG module for Maximum SID Depths (MSDs) Types. The second augments the IETF MPLS YANG model to provide support for MPLS MSDs as defined in RFC 8476 and RFC 8491.

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 6 December 2024.

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Table of Contents

1. Overview

YANG [RFC7950] is a data modeling language used to define the contents of a conceptual data store that allows networked devices to be managed using NETCONF [RFC6241] or RESTCONF [RFC8040].

There are two YANG modules defined in this document. Module iana-msd-types defines the identities for Maximum SID Depth (MSD) Types as per the IANA the IGP MSD-Types registry [IANA-IGP-MSD-Types]. This document also defines module ietf-mpls-msd augmenting the IETF MPLS YANG model [RFC8960], which itself augments the routing RIB data model [RFC8349], to provide operational state for various MSDs[RFC8662]. The module augments the base MPLS model with a list of various types of node MSDs, as well as various types of MSDs on links.

The YANG modules in this document conform to the Network Management Datastore Architecture (NMDA) [RFC8342].

2. Design of the Model

2.1. IANA MSD Types Module

IANA has created an IANA-managed registry titled "IGP MSD-Types" under the "Interior Gateway Protocol (IGP) Parameters" registry to identify MSD-Types. Module iana-msd-types is an IANA-maintained module, which defines the identities for the MSD-Types as in the IANA IGP MSD-Types registry.

On top of the base identity "msd-base", identity "msd-base-mpls" is defined to serve as the base for MSD types for MPLS data plane, and identity "msd-base-srh" is defined to serve as the base for MSD types for Segment Routing Header (SRH) in IPv6 data plane.

This module will be maintained by IANA and updated if and when there is any change to the registry.

2.2. IETF MPLS MSD Module

Module ietf-mpls-msd augments the base MPLS model [RFC8960], and it provides support of different types of MSDs in MPLS data plane.

As defined in [RFC8491], MSD is the number of SIDs supported by a node or a link on a node. The module defines lists of MSDs with different MSD Types for a node and links. Please note that these are read-only data as per the node's hardware capability.

3. Tree for IETF MPLS MSD Types YANG Module

This document uses the graphical representation of data models per [RFC8340].

module: ietf-mpls-msd

  augment /rt:routing/mpls:mpls:
    +--ro node-msds
       +--ro node-msd* [msd-type]
          +--ro msd-type     identityref
          +--ro msd-value    uint8
  augment /rt:routing/mpls:mpls/mpls:interfaces/mpls:interface:
    +--ro link-msds
       +--ro link-msd* [msd-type]
          +--ro msd-type     identityref
          +--ro msd-value    uint8

4. YANG Modules

There are two YANG modules defined in this document.

4.1. IANA-Maintained Module for MSD-Types

This document defines the initial version of the IANA-maintained YANG module for MSD Types, which mirrors the IANA IGP MSD-Types registry [IANA-IGP-MSD-Types].

<CODE BEGINS> file "iana-msd-types@2024-06-04.yang"

module iana-msd-types {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:iana-msd-types";
  prefix iana-msd-types;

  organization
    "Internet Assigned Numbers Authority (IANA)";

  contact
    "Internet Assigned Numbers Authority

     ICANN
     12025 Waterfront Drive, Suite 300
     Los Angeles, CA 90094-2536
     United States of America

     Tel:    +1 310 301 5800
     <mailto:iana@iana.org>";

  description
    "The YANG module defines the identities for Maximum Segment
     Identifier (SID) Depth (MSD) Types.

     This YANG module is maintained by IANA and reflects the 'IGP
     MSD-Types' registry.

     Copyright (c) 2024 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 Revised 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 initial version of this YANG module is part of RFC XXXX
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
     for full legal notices.

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

     //RFC Ed.: replace IANA_FOO_URL and remove this note.

     The latest version of this YANG module is available at
     <IANA_FOO_URL>.";

  revision 2024-06-04 {
    description
      "Initial Version";
    reference
      "RFC XXXX: YANG Data Model for MPLS Maximum Segment
                 Identifier (SID) Depth (MSD)";
  }

  identity msd-base {
    description
      "Base identity for Maximum SID Depth (MSD) Type. The MSD type
       definition is defined in IANA IGP MSD-Types registry.";
  }

  identity msd-base-mpls {
    base msd-base;
    description
      "Identity for MSD types for MPLS data plane.";
  }

  identity base-mpls-imposition-msd {
    base msd-base-mpls;
    description
      "Base MPLS Imposition MSD.";
    reference
      "RFC 8491: Signaling Maximum SID Depth (MSD) using IS-IS
       RFC 8476: Signaling Maximum SID Depth (MSD) using OSPF
       RFC 8664: Path Computation Element Communication Protocol
                 (PCEP) Extensions for Segment Routing
       RFC 8814: Signaling Maximum SID Depth (MSD) Using the Border
                 Gateway Protocol - Link State";
  }

  identity erld-mpls {
    base msd-base-mpls;
    description
      "msd-erld is defined to advertise the Entropy Readable
       Label Depth (ERLD).";
    reference
      "RFC 8662: Entropy Label for Source Packet Routing in
                 Networking (SPRING) Tunnels
       RFC 9088: Signaling Entropy Label Capability and Entropy
                 Readable Label Depth Using IS-IS";
  }

  identity msd-base-srh {
    base msd-base;
    description
      "Identity for MSD types for Segment Routing Header (SRH).";
  }

  identity srh-max-sl {
    base msd-base-srh;
    description
      "The Maximum Segment Left MSD type.";
    reference
      "RFC 9352: IS-IS Extensions to Support Segment Routing
                 over the IPv6 Data Plane";
  }

  identity srh-max-end-pop {
    base msd-base-srh;
    description
      "The Maximum End Pop MSD Type.";
    reference
      "RFC 9352: IS-IS Extensions to Support Segment Routing
                 over the IPv6 Data Plane";
  }

  identity srh-max-h-encaps {
    base msd-base-srh;
    description
      "The Maximum H.Encaps MSD Type.";
    reference
      "RFC 9352: IS-IS Extensions to Support Segment Routing
                 over the IPv6 Data Plane";
  }

  identity srh-max-end-d {
    base msd-base-srh;
    description
      "The Maximum End D MSD Type.";
    reference
      "RFC 9352: IS-IS Extensions to Support Segment Routing
                 over the IPv6 Data Plane";
  }
}

<CODE ENDS>

4.2. MPLS MSD YANG

This document also defines a YANG module for MSD extensions [RFC8476][RFC8491] to MPLS base model as defined in [RFC8960].

<CODE BEGINS> file "ietf-mpls-msd@2024-06-04.yang"

module ietf-mpls-msd {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-mpls-msd";
  prefix mpls-msd;

  import ietf-routing {
    prefix rt;
    reference
      "RFC 8349: A YANG Data Model for Routing
                 Management (NMDA Version)";
  }
  import ietf-mpls {
    prefix mpls;
    reference
      "RFC 8960: A YANG Data Model for MPLS Base";
  }
  import iana-msd-types {
    prefix iana-msd-types;
  }

  organization
    "IETF Multiprotocol Label Switching (MPLS) Working Group";
  contact
    "WG Web:   <https://datatracker.ietf.org/wg/mpls/>
     WG List:  <mailto:mpls@ietf.org>

     Author:    Yingzhen Qu
               <mailto:yingzhen.ietf@gmail.com>
     Author:    Acee Lindem
               <mailto:acee.ietf@gmail.com>
     Author:    Stephane Litkowski
               <mailto:slitkows.ietf@gmail.com>
     Author:    Jeff Tantsura
               <mailto:jefftant.ietf@gmail.com>

    ";
  description
    "The YANG module augments the base MPLS model, and it is to
     provide support for different types of Maximum SID Depth (MSD).

     This YANG model conforms to the Network Management
     Datastore Architecture (NMDA) as described in RFC 8342.

     Copyright (c) 2024 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 Revised 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;
     see the RFC itself for full legal notices.";

  revision 2024-06-04 {
    description
      "Initial Version";
    reference
      "RFC XXXX: YANG Model for MPLS Maximum Segment
                 Identifier (SID) Depth (MSD)";
  }

  grouping msd-type-value {
    description
      "Grouping for MSD type and value.";
    leaf msd-type {
      type identityref {
        base iana-msd-types:msd-base-mpls;
      }
      mandatory true;
      description
        "MSD types. The MSD type is defined in IANA IGP
         MSD-Types registry.";
    }
    leaf msd-value {
      type uint8;
      mandatory true;
      description
        "MSD value, in the range of 0-255. 0 represents the lack
         of ability to support a SID statck of any depth.";
    }
  }
  augment "/rt:routing/mpls:mpls" {
    description
      "This module augments MPLS data model (RFC 8960)
       with node MSD.";
    container node-msds {
      config false;
      description
        "Maximum SID Depth (MSD) of a node.";
      list node-msd {
        key "msd-type";
        uses msd-type-value;
        description
          "List of different types of node MSDs. For the same
          type, the value of node MSD is the smallest among link MSD
          values.";
      }
    }
  }

  augment "/rt:routing/mpls:mpls/mpls:interfaces/mpls:interface" {
    description
      "This module augments MPLS data model (RFC 8960)
       with link MSD.";
    container link-msds {
      config false;
      description
        "Maximum SID Depth (MSD) of an interface.";
      list link-msd {
        key "msd-type";
        uses msd-type-value;
        description
          "List of different types of MSDs on the link.";
      }
    }
  }
}

<CODE ENDS>

5. Security Considerations

The YANG modules specified in this document define 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 (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a pre-configured subset of all available NETCONF or RESTCONF protocol operations and content.

Some of the readable data nodes in the modules 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:

6. IANA Considerations

6.1. Registering YANG Modules

This document registers URIs in the IETF XML registry [RFC3688]. Following the format in [RFC3688], the following registrations is requested to be made:

   URI: urn:ietf:params:xml:ns:yang:iana-msd-types
   Registrant Contact: IANA.
   XML: N/A, the requested URI is an XML namespace.

   URI: urn:ietf:params:xml:ns:yang:ietf-mpls-msd
   Registrant Contact: The IESG.
   XML: N/A, the requested URI is an XML namespace.

This document registers the YANG modules in the YANG Module Names registry [RFC6020].

   name: iana-msd-types
   namespace: urn:ietf:params:xml:ns:yang:iana-msd-types
   prefix: iana-msd-types
   reference: RFC XXXX

   name: ietf-mpls-msd
   namespace: urn:ietf:params:xml:ns:yang:ietf-mpls-msd
   prefix: mpls-msd
   reference: RFC XXXX

6.2. IANA MSD-Types Module

This document defines the initial version of the IANA-maintained "iana-msd-types" YANG module Section 4.1. The latest version of the YANG module is available from the "YANG Parameters" registry [IANA-YANG-Parameters].

IANA is requested to add this note to the "YANG Module Names" registry:

The identities defined in the iana-msd-types YANG module are organized hierarchically based on the data plane. In this initial version, only MPLS and SRv6 data planes are supported, hence "msd-base-mpls" and "msd-base-srh" are defined. When a new data plane is added to the "IGP MSD-Types" registry, a new "identity" statement should be added to the "iana-msd-types" YANG module. The name of the "identity" is the prefix "msd-base-" plus a lower-case version of the data plane name . The identity statement should have the following sub-statements defined:

"base":
Contains 'msd-base'.
"description":
Replicates the description from "msd-base-mpls" and change the corresponding data plane name.
"reference":
Replicates the reference from the registry with the title of the document added.

When a MSD type is added to the "IGP MSD-Types" registry, a new "identity" statement must be added to the "iana-msd-types" YANG module. Then name of the "identity" is a lower-case version of the type name provided in the description. The "identity" statement should have the following sub-statements defined:

"base":
Contains the base name of the corresponding data plane.
"description":
Replicates the description from the registry.
"reference":
Replicates the reference from the registry with the title of the document added.

Unassigned or reserved values are not present in the module.

When the "iana-msd-types" YANG module is updated, a new "revision" statement with a unique revision date must be added in front of the existing revision statements.

IANA is requested to add this note to [IANA-IGP-MSD-Types]:

7. Acknowledgements

This document was produced using Marshall Rose's xml2rfc tool.

The YANG model was developed using the suite of YANG tools written and maintained by numerous authors.

We would like to thank Jan Lindblad, Tom Petch, Dhruv Dhody, Mohamed Boucadair and Susan Hares for their reviews and comments.

8. References

8.1. Normative References

[IANA-IGP-MSD-Types]
IANA, "IGP MSD-Types", <https://www.iana.org/assignments/igp-parameters>.
[IANA-YANG-Parameters]
IANA, "YANG Module Names", <https://www.iana.org/assignments/yang-parameters>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[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>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[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>.
[RFC8349]
Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for Routing Management (NMDA Version)", RFC 8349, DOI 10.17487/RFC8349, , <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, , <https://www.rfc-editor.org/info/rfc8446>.
[RFC8476]
Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak, "Signaling Maximum SID Depth (MSD) Using OSPF", RFC 8476, DOI 10.17487/RFC8476, , <https://www.rfc-editor.org/info/rfc8476>.
[RFC8491]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, "Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491, DOI 10.17487/RFC8491, , <https://www.rfc-editor.org/info/rfc8491>.
[RFC8960]
Saad, T., Raza, K., Gandhi, R., Liu, X., and V. Beeram, "A YANG Data Model for MPLS Base", RFC 8960, DOI 10.17487/RFC8960, , <https://www.rfc-editor.org/info/rfc8960>.

8.2. 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>.
[RFC8662]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S., Shakir, R., and J. Tantsura, "Entropy Label for Source Packet Routing in Networking (SPRING) Tunnels", RFC 8662, DOI 10.17487/RFC8662, , <https://www.rfc-editor.org/info/rfc8662>.

Authors' Addresses

Yingzhen Qu
Futurewei Technologies
Acee Lindem
LabN Consulting, L.L.C.
Stephane Litkowski
Cisco Systems
Jeff Tantsura
Nvidia