Internet-Draft DetNet Applied to IETF NS March 2023
Song & Wu Expires 10 September 2023 [Page]
Workgroup:
DetNet Working Group
Internet-Draft:
draft-sw-detnet-network-slice-mapping-yang-02
Published:
Intended Status:
Standards Track
Expires:
Authors:
X. Song
ZTE Corp.
H. Wu
ZTE Corp.

YANG Data Model for DetNet Mapping with Network Slice

Abstract

The convergence of IETF Network Slicing with DetNet achieves adequate network resource allocation and reservation to each node along the way of DetNet flows for latency-sensitive services. This document introduces the applicability of DetNet to network slice , DetNet mapping with Network Slice requirements and YANG data models extensions in the context of IP/ MPLS network.

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 10 September 2023.

1. Introduction

Deterministic Networking (DetNet) is a service that can be offered by a network to DetNet flows. As defined in [RFC8655], DetNet flows provide deterministic services with guaranteed performance such as end-to-end delay and low packet loss rate for unicast or multicast data streams. The adequate network resource allocation and reservation are required for DetNet flows. DetNet assumes that DetNet control plane using traditional technologies such as RSVP-TE, SR to achieve bandwidth and buffer resources allocation at each DetNet node along the path of DetNet flows. The DetNet data plane according to the existing DetNet mechanism makes best effort to forward data packets with no network resource reservation and occupation guarantee.

[I-D.ietf-teas-ietf-network-slices] provides the definition of network slice in the context of IETF network and discusses the main characteristics, necessary components and interfaces for the general framework of IETF Network Slice. An IETF Network Slice delivers a service to a customer by meeting connectivity resource requirements and associated network capabilities identified as SLOs and SLEs. The parameters for SLOs include guaranteed minimum bandwidth, guaranteed maximum latency, maximum permissible delay variation and Maximum Permissible Packet Loss Rate. In order to support SLOs guarantee for slice flows, the network resources need to be partitioned in both control plane and data plane. [I-D.ietf-teas-ns-ip-mpls] provides a solution to resolve this problem. It introduces NRP (Network Resource Partition) and NRP policy to construct IETF Network Slice to address the requirements of network slicing in packet networks. To realize the adequate network resource allocation at control plane and necessary network resource reservation at data plane, the resource reservation on each link needs to be NRP aware, e.g., the traditional technology such as RSVP-TE used at control plane is not enough, the NRP state aware Traffic Engineering (NRP-TE) is needed.

This document describes the applicability of DetNet to IETF Network Slice. The convergence of DetNet with IETF Network Slice helps the deterministic service delivery with adequate network resource allocation and reservation on each node along the path of DetNet flows.

2. Conventions

2.1. Requirements Language

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.

2.2. Terminology

Refer to [RFC8655], [RFC8938] and [I-D.ietf-teas-ietf-network-slices], for the key terms used in this document.

The terminology for describing YANG data models is found in [RFC7960].

2.3. Abbreviations

DetNet: Deterministic Networking

IETF NS: IETF Network Slice

MPLS: Multi-Protocol Label Switching

NETCONF: Network Configuration Protocol

NRP: Network Resource Partition

PREOF: Packet Replication, Elimination, and Ordering Functions

SDP: Service Demarcation Point

SLE: Service Level Expectation

SLO: Service Level Objective

SSH: transport Secure Shell

TLS: Transport Layer Security

3. Applicability of DetNet to Network Slice

3.1. Use Case

Refer to [RFC8578] the use case of DetNet applied to Network Slicing is described in section 10:

  • Resource distribution across slices.
  • Deterministic services within slices.

The IETF Network Slicing enables a diverse set of applications with different SLOs (Service Level Objectives) guarantee to coexist over a shared underlay network. The NRP defined in [I-D.ietf-teas-ns-ip-mpls] provides one solution to address SLO guarantee problem. With the use of NRP and NRP policy network resource allocation and reservation are achieved at each node in IP/MPLS network. Through the applicability of IETF Network Slice to DetNet the sufficient network bandwidth and buffer resources are allocated and reserved at each node along the path of the DetNet flow to deliver deterministic service.

The following figure shows an example for the applicability of DetNet to Network Slice.

                            __________    _____
         +-----------+     /          \__/     \    +-----------+
  End A  | +-------+ |    /+-------+  +-------+ \   | +-------+ |   End B
   ------|-|+-----+| |   / |+-----+|  |+-----+|  |  | |+-----+|--------
   UNI-A | ||     || |==|==||     ||==||     ||==|==| ||     || | UNI-B
         | ||DSI-1|| |  |  ||NRP-1||  ||NRP-1||  |  | ||DSI-1|| |
         | |+-----+| |  |  |+-----+|  |+-----+|  /  | |+-----+| |
         | |NRP-1  | |   \ |Pm     |  |Pn     | |   | |NRP-1  | |
         | +-------+ |    \+-------+  +-------+ |   | +-------+ |
                 | PEa       |     \                    |   | PEb       |
         +-----------+     |___IP/MPLS_Network_/    +-----------+
            |                                               |
            |-------DSI over NRP over IP/MPLS tunnel -------|


Figure 1: DetNet mapping with Network Slice example

The App-flow user applies for low-latency deterministic service. The packets belonging to the flow are filtered and classified to DetNet-specific flows. The DetNet Service Instance (DSI-1) is terminated at end system A and B. In order to meet the network resource guarantee the user of the DetNet-specific flow applies for necessary network resources. The IETF NSC after received the request sends NRP profile/policy to the underlying network nodes and the underling PE and P nodes make corresponding network resource reservation at the right path based on path computation of NRP profile/policy. In order to achieve adequate network resource allocation, the edge routers (e.g., PE) should be able to identify a packet belonging to DetNet-specific flow and its mapping with the IETF Network Slice instance. The DetNet flow should has slice-aware capability to realize necessary network resources allocation and reservation on each node between the end systems A and B. At data plane the DetNet nodes should support the NRP-ID and NRP-Label field encapsulation. Then the added NRP-ID and NRP-Label fields parsed and processed by each node along the path direction of the DetNet flow for the distribution of the local NRP strategy and the reservation of network resources.

3.2. Modes of IETF Network Slice Selection

This document provides three modes of IETF Network Slice selection operations as associated with DetNet follows. Additional modes may be defined in the future.

  • New IETF Network Slice Binding - A customer may request a DetNet service with requirements guarantee, e.g., end-to-end latency, latency variation, jitter, etc. To satisfy the customer's requirements on network resource it's recommended to bind DetNet flows with an IETF Network Slice instance. The YANG model described in Section 5 of this document provides the mapping between DetNet flows with a new IETF Network Slice.
  • IETF Network Slice Sharing - A customer may request a DetNet service with requirement guarantee where a new IETF Network Slice do not need to be created but be shared with other multiple DetNet flows. The mapping YANG model described in Section 5 of this document provides the mapping between DetNet flows with an IETF Network Slice in use. No modification of the properties of an IETF Network Slice is allowed in this mode.
  • IETF Network Slice Modification - This mode allows the modification of the properties of the existing IETF Network Slice (e.g., bandwidth, latency, etc.).

IETF Network Slice Mapping Template - A policy profile which contains network constraints and optimization criteria is used for mapping DetNet flows to one/more certain IETF Network Slice instance.

4. Mapping DetNet with Network Slice

4.1. Mapping Requirements

DetNet service is per flow (including app-layer, service-layer and forwarding-layer flow), performs traffic processing based on the identification for flow/flow aggregation. Differences in IETF Network Slice service are considered in terms of Network Resource Partition. [I-D.ietf-teas-ns-ip-mpls] introduces a mechanism to associate Network Resource Partition (NRP) with Slice-Flow Aggregate. If DetNet applied to IETF Network Slice, the DetNet-flow/flow aggregation is considered as the slice-flow/flow aggregation over the underlying NRP.

Requirements for Network Slice mapping with deterministic networking services:

  • The mapping of deterministic services with underlying network slice resources is necessary. It may include:

    • Service endpoint mapping between DetNet Edge Node and IETF Network Slice SDP.
    • Access service mapping between DetNet UNI and IETF Network Slice AC.
    • Instance mapping between DetNet-flow/flow aggregations with IETF Network Slice.
  • The creation request for network slice instance to be bounded with one specific deterministic flow/flow aggregation instances should be supported.
  • The sharing of network slice instance for one or more deterministic flow/flow aggregation instances SHOULD be supported.
  • Configurations for a new network slice instance to provide necessary underlying resource to deterministic services is necessary.
  • Modification for an existing network slice instance applied to one or more DetNet flow SHOULD be supported.

4.2. Mapping Process

  • APP-flow packets is instantiated as DetNet service awareness flow.
  • If there is an existing IETF Network Slice instance which satisfies the network resource requirements of the DetNet customer. After check the feasibility of the IETF Network Slice instance bound to DetNet flows, request mapping DetNet-flow/flow aggregations with IETF Network Slice instance.
  • If there is no IETF Network Slice available, a new IETF Network Slice instance creation is required.
  • The mapping of DetNet flow with IETF Network Slice is configured and stored in management plane. The mapping policy of DetNet flow associated with underlying network resource partition (NRP) is programmed to the DetNet or IETF Network Slice Nodes (such as SDP, P nodes, etc.) through YANG data models.
  • In data plane, the DetNet or IETF Network Slice Nodes complete the identification of deterministic service flows (such as IP 6-tuple, MPLS labels, etc.) and correspond with one specific network slice instance , realize the slice awareness of DetNet flow/flow aggregation. Through the network resource occupation of hop-by-hop nodes along the path, network resources required by the deterministic networking service flow is guaranteed.

5. YANG Modeling Approach

This section provides how the DetNet and IETF Network Slice Service mapping parameters are supported using augmentation of the existing DetNet service models (i.e., [I-D.ietf-detnet-yang]). It identifies the YANG data models being defined by the IETF to support this deployment architecture and specific scenarios relevant for Service Providers.

The below figure shows the modeling approach of the Augmented DetNet Model.

+--------------+        +----------------------+
|    DetNet    |o-------|                      |
+--------------+ augment|                      |
                        |                      |
+--------------+        |Augmented DetNet Model|
| DetNet & NS  |------->|                      |
| Mapping Types| import |                      |
+--------------+        |                      |
                        +----------------------+
Figure 2: Modeling approach

6. YANG Data Tree

6.1. Service Mapping Types

   module: ietf-ns-detnet-mapping-types
     +--rw ns-mapping-templates
        +--rw ns-mapping-template* [id]
           +--rw id                  string
           +--rw description?        string
           +--rw map-type?           identityref
                   +--rw ns-slo-ref?
                           ->/nss:slo-sle-templates/slo-sle-template/id

6.2. Service Models

module: ietf-ns-detnet-service-mapping
    augment /dnet:service/dnet:sub-layers/dnet:sub-layer:
      +--rw ns-detnet-mapping
         +--rw ns-mapping
            +--rw map-type?                       identityref
            +--rw ns-id                           string
            +--rw ns-mapping-template-ref?
                    -> /nsdmt:ns-mapping-templates/ns-mapping-template/id
                    {template}?

7. YANG Data Model

7.1. Service Mapping Types

<CODE BEGINS> file "ietf-ns-detnet-mapping-types@2023-03-06.yang"

   module ietf-ns-detnet-mapping-types {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-ns-detnet-mapping-types";
     prefix nsdmt;

     import ietf-network-slice-service {
          prefix nss;
       reference
         "I-D.ietf-teas-ietf-network-slice-nbi-yang-01: A YANG Data
                 Model for the IETF Network Slice";
     }

     organization
       "IETF DetNet Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/detnet/>
        WG List:  <mailto:detnet@ietf.org>

        Editor:   Xueyan Song
                  <song.xueyan2@zte.com.cn>
        Editor:   Haisheng Wu
                  <wu.haisheng@zte.com.cn>";
     description
       "This module contains a YANG module for IETF Network Slice &
           Detnet mapping parameters.

        Copyright (c) 2022 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 2023-03-06 {
       description
         "Initial revision.";
       reference
         "RFC XXXX:  YANG Data Model for DetNet Mapping with Networ
                 Slice";
     }

     /*
      * Features
      */

     feature template {
       description
         "Support Network Slice mapping templates.";
     }

     /*
      * Identity for map-type
      */

     identity map-type {
       description
         "Base identity from which specific map types are derived.";
     }

     identity new {
       base map-type;
       description
         "The new Network Slice are binded to the service.";
     }

     identity select {
       base map-type;
       description
         "The Detnet service selects an existing Network Slice with no
          modification.";
     }

     identity modify {
       base map-type;
       description
         "The Detnet service selects an existing Network Slice and
                 allows to modify the properties of the Network Slice
                 (e.g., SLO)";
     }

     identity none {
       base map-type;
       description
         "The Detnet service is not mapped to any underlying Network
                 Slice";
     }


     /*
      * Typedef
      */

     typedef ns-mapping-template-id {
       type string;
       description
         "Identifier for Network Slice mapping template.";
     }

     /*
      * Groupings
      */

     grouping ns-ref {
       description
         "The reference to Network Slice.";

       leaf ns-mapping-slice-id{
               type uint32;
               description
                  "Identifier for a Network Slice.";
            }

       leaf ns-mapping-template-ref {
         if-feature "template";
         type leafref {
           path "/nsdmt:ns-mapping-templates/"
              + "nsdmt:ns-mapping-template/nsdmt:id";
         }
         description
           "An identifier to the Network Slice Mapping Template
                   where the Network Slice constraints and optimization
                   criteria are specified.";
       }
     }


     grouping ns-mapping {
       description
         "Mapping between Services and network-slice";
       container ns-mapping {
         description
           "Mapping between Services and network-slice";
         leaf map-type {
           type identityref {
             base map-type;
           }
           description
             "Isolation Requirements";
         }
         uses ns-ref;
       }
     }

     //grouping

     container ns-mapping-templates {
       description
         "The network-slice constraints and optimization
                 criteria";
       list ns-mapping-template {
                 key "id";
                 description
            "network-slice template";
         leaf id {
           type ns-mapping-template-id;
           description
             "Identification of the Template to be used.";
         }
         leaf description {
           type string;
           description
             "Description of the template.";
         }
         leaf map-type {
           type identityref {
             base map-type;
           }
           must "0 = derived-from-or-self(.,'none')" {
             error-message "The map-type must be other than "
                         + "none";
           }
           description
             "Map type for Network Slice creation/
              selection.";
         }
          leaf ns-slo-ref{
                     type leafref {
                                  path "/nss:network-slice-services"
                                                                        + "/nss:slo-sle-templates"
                                                                        + "/nss:slo-sle-template"
                                                                        + "/nss:id";
                 }

         description
           "List for templates.";
       }
     }
    }
   }

<CODE ENDS>

7.2. Service Models

<CODE BEGINS> file "ietf-ns-detnet-service-mapping@2023-03-06.yang"

   module ietf-ns-detnet-service-mapping {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-ns-detnet-service-mapping";
     prefix detnet-nssm;


     import ietf-ns-detnet-mapping-types {
       prefix nsdmt;
       reference
         "RFC XXXX:  YANG Data Model for DetNet Mapping with Network
                 Slice";
     }
     import ietf-detnet {
       prefix dnet;
       reference
           "I-D.draft-ietf-detnet-yang: YANG Data Model for Detnet";
     }

     organization
       "IETF DetNet Working Group";

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

        Editor:   Xueyan Song
                  <song.xueyan@zte.com.cn>
        Editor:   Haisheng Wu
                  <wu.haisheng@zte.com.cn>";

     description
       "This module contains a YANG module for the mapping of DetNet
           to the Network Slice.

        Copyright (c) 2022 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 2023-03-06 {
       description
         "Initial revision.";
       reference
         "RFC XXXX:  YANG Data Model for DetNet Mapping with Network
                 Slice";
     }


     /*
      * Augmentation to Detnet
      */

      augment "/dnet:detnet/dnet:service/dnet:sub-layer"{
       description
         "Detnet augmented to include Network Slice parameters and
                 mapping";
       container ns-detnet-mapping {
         presence "Indicates Detnet service to Network Slice mapping";
         description
           "Container to augment detnet to Network Slice parameters
                   and mapping";
         uses nsdmt:ns-mapping;
       }
     }

     //augment

   }

<CODE ENDS>

8. IANA Considerations

This document requests the IANA to register the following URIs in the "IETF XML Registry" [RFC3688].

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

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

This document requests the IANA to register the following YANG modules in the YANG Module Names registry [RFC7950].

        Name: ietf-ns-detnet-mapping-types
        Namespace: urn:ietf:params:xml:ns:yang: ietf-ns-detnet-mapping-types
        Prefix: nsdmt
        Reference: [This.I-D]

        Name: ietf-ns-detnet-service-mapping
        Namespace: urn:ietf:params:xml:ns:yang: ietf-ns-detnet-service-mapping
        Prefix: detnet-nssm
        Reference: [This.I-D]


9. Security Considerations

Security considerations for DetNet are covered in the DetNet Architecture [RFC8655] and DetNet Security Considerations [RFC9055]

The YANG data model specified in this document defines a schema for mapping of DetNet with IETF Network Slice via NETCONF [RFC6241] or RESTCONF [RFC8040]. For NETCONF to support secure transport Secure Shell (SSH) [RFC6242] is mandatory. For RESTCONF to support secure transport TLS [RFC8446] is mandatory.

10. Acknowledgement

The authors appreciate Peng Shaofu and Liu Aihua for useful discussions and motivations for this work.

11. References

11.1. Normative References

[I-D.ietf-detnet-yang]
Geng, X., Ryoo, Y., Fedyk, D., Rahman, R., and Z. Li, "Deterministic Networking (DetNet) YANG Model", Work in Progress, Internet-Draft, draft-ietf-detnet-yang-17, , <https://datatracker.ietf.org/doc/html/draft-ietf-detnet-yang-17>.
[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>.
[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>.
[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>.
[RFC8655]
Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", RFC 8655, DOI 10.17487/RFC8655, , <https://www.rfc-editor.org/info/rfc8655>.

11.2. Informative References

[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani, K., Contreras, L. M., and J. Tantsura, "A Framework for IETF Network Slices", Work in Progress, Internet-Draft, draft-ietf-teas-ietf-network-slices-19, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ietf-network-slices-19>.
[I-D.ietf-teas-ns-ip-mpls]
Saad, T., Beeram, V. P., Dong, J., Wen, B., Ceccarelli, D., Halpern, J. M., Peng, S., Chen, R., Liu, X., Contreras, L. M., Rokui, R., and L. Jalil, "Realizing Network Slices in IP/MPLS Networks", Work in Progress, Internet-Draft, draft-ietf-teas-ns-ip-mpls-01, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ns-ip-mpls-01>.
[RFC7960]
Martin, F., Ed., Lear, E., Ed., Draegen, T., Ed., Zwicky, E., Ed., and K. Andersen, Ed., "Interoperability Issues between Domain-based Message Authentication, Reporting, and Conformance (DMARC) and Indirect Email Flows", RFC 7960, DOI 10.17487/RFC7960, , <https://www.rfc-editor.org/info/rfc7960>.
[RFC8578]
Grossman, E., Ed., "Deterministic Networking Use Cases", RFC 8578, DOI 10.17487/RFC8578, , <https://www.rfc-editor.org/info/rfc8578>.
[RFC8938]
Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S. Bryant, "Deterministic Networking (DetNet) Data Plane Framework", RFC 8938, DOI 10.17487/RFC8938, , <https://www.rfc-editor.org/info/rfc8938>.
[RFC9055]
Grossman, E., Ed., Mizrahi, T., and A. Hacker, "Deterministic Networking (DetNet) Security Considerations", RFC 9055, DOI 10.17487/RFC9055, , <https://www.rfc-editor.org/info/rfc9055>.

Authors' Addresses

Xueyan Song
ZTE Corp.
Nanjing
China
Haisheng Wu
ZTE Corp.
Nanjing
China