| Internet-Draft | DetNet Applied to IETF NS | March 2023 |
| Song & Wu | Expires 10 September 2023 | [Page] |
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.¶
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This Internet-Draft will expire on 10 September 2023.¶
Copyright (c) 2023 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
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.¶
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.¶
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].¶
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¶
Refer to [RFC8578] the use case of DetNet applied to Network Slicing is described in section 10:¶
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 -------|
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.¶
This document provides three modes of IETF Network Slice selection operations as associated with DetNet follows. Additional modes may be defined in the future.¶
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.¶
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:¶
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 | |
+--------------+ | |
+----------------------+
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
¶
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}?
¶
<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>¶
<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>¶
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]
¶
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.¶
The authors appreciate Peng Shaofu and Liu Aihua for useful discussions and motivations for this work.¶