]> Ericsson

jonas.ahlberg@ericsson.com

Ericsson

scott.mansfield@ericsson.com

Huawei Technologies

amy.yemin@huawei.com

Huawei Technologies

italo.busi@huawei.com

NEC Laboratories Europe

xi.li@neclab.eu

Nokia - IT

daniela.spreafico@nokia.com

Routing ccamp Internet-Draft This document defines a YANG data model to describe bandwidth availability for a link in a network topology. Discussion Venues Source for this draft and an issue tracker can be found at .

Introduction This document defines a YANG data model to describe bandwidth availability for a link. It is an important characteristic of links with variable bandwidth, where each level of bandwidth can be associated with a certain level of availability. An example of such a link is microwave radio link, where the bandwidth can be dynamically adapted to changing signal conditions, impacted by interference & fading, in order to guarantee the required quality of the link at every single moment. defines a mechanism to report bandwidth-availability information through OSPF-TE, but it could also be useful for a controller to access such bandwidth-availability information as part of the topology model when performing a path/route computation. The model augments "YANG Data Model for Traffic Engineering (TE) Topologies" defined in , which is based on "A YANG Data Model for Network Topologies" defined in . The bandwidth availability model is expected to be used between a Provisioning Network Controller (PNC) and a Multi Domain Service Coordinator(MDSC) . Examples of use cases that can be supported are:

1. Propagation of relevant characteristics of a link, including bandwidth availability, to higher topology layers, where it e.g. could be used as a criterion when configuring and optimizing a path for a connection/service through the network end to end.
2. A link could dynamically adjust its bandwidth according to changes in the signal conditions. defines a mechanism to report bandwidth-availability information through OSPF-TE, but it could also be useful for a controller to access such bandwidth-availability information as part of the topology model when performing a path/route computation.

Terminology and Definitions The following acronyms are used in this document: PNC Provisioning Network Controller MDSC Multi Domain Service Coordinator

Tree Structure A simplified graphical representation of the data model is used in chapter 3.1 of this document. The meaning of the symbols in these diagrams is defined in .

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 when, and only when, they appear in all capitals, as shown here.

Bandwidth Availability Topology YANG Data Model

YANG Tree

Bandwidth Availability Topology YANG Data Module Editor: Jonas Ahlberg Editor: Scott Mansfield Editor: Min Ye Editor: Italo Busi Editor: Xi Li Editor: Daniela Spreafico "; description "This is a module for defining bandwidth availability matrix, for links in a topology. It is intended to be used in conjunction with an instance of ietf-network-topology and its augmentations. Example use cases include: - Defining bandwidth availability matrix for a microwave link - Defining bandwidth availability matrix for a LAG link comprising of two or more member links Copyright (c) 2023 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 (https://tools.ietf.org/html/rfcXXXX); see the RFC itself for full legal notices."; revision 2023-02-15 { description "First rough draft."; reference ""; } /* * Groupings */ grouping link-bw-availability-table { description "Grouping used for bandwidth availability."; list link-availability{ key "availability"; description "Table describing the bandwidths available at corresponding availability level for a link."; leaf availability { type decimal64 { fraction-digits 4; range "0..99.9999"; } description "Availability level"; } leaf link-bandwidth { type uint64; units "Kbps"; description "The link bandwidth corresponding to the availability level"; } } leaf actual-bandwidth{ type yang:gauge64; units "bits/second"; config false; description "An estimate of the link's current bandwidth in bits per second. Related to the data node speed in RFC 8343."; reference "RFC 8343: A YANG Data Model for Interface Management"; } } /* * Data nodes */ augment "/nw:networks/nw:network/nt:link/tet:te/" + "tet:te-link-attributes" { description "Augmenting link with link bandwidth availability matrix."; uses link-bw-availability-table; } } ]]>

Security Considerations The YANG module specified in this document defines schemas for data that is designed to be accessed via network management protocols such as NETCONF or RESTCONF . The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS . The NETCONF access control model 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 specified in this document imports and augments the ietf-network and ietf-network-topology models defined in . The security considerations from are applicable to the module in this document. There are a several 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 data nodes and their sensitivity/vulnerability: In the "ietf-bandwidth-availability-topology" module:

• availability: A malicious client could attempt to modify the availability level which could modify the intended behavior.
• link-bandwidth: A malicious client could attempt to modify the link bandwidth which could either provide more or less link bandwidth at the indicated availability level, changing the resource allocation in unintended ways.

IANA Considerations IANA is asked to assign a new URI from the "IETF XML Registry" as follows: It is proposed that IANA should record YANG module names in the "YANG Module Names" registry as follows:

References Normative References This document defines a YANG data model for representing, retrieving, and manipulating Traffic Engineering (TE) Topologies. The model serves as a base model that other technology-specific TE topology models can augment. This document defines an abstract (generic, or base) YANG data model for network/service topologies and inventories. The data model serves as a base model that is augmented with technology-specific details in other, more specific topology and inventory data models. In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK] This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations. The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model. This document obsoletes RFC 6536. This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] Informative References A network may contain links with variable discrete bandwidth, e.g., microwave and copper. The bandwidth of such links may change discretely in response to a changing external environment. The word "availability" is typically used to describe such links during network planning. This document defines a new type of Generalized Switching Capability-Specific Information (SCSI) TLV to extend the Generalized Multiprotocol Label Switching (GMPLS) Open Shortest Path First (OSPF) routing protocol. The extension can be used for route computation in a network that contains links with variable discrete bandwidth. Note that this document only covers the mechanisms by which the availability information is distributed. The mechanisms by which availability information of a link is determined and the use of the distributed information for route computation are outside the scope of this document. It is intended that technology-specific documents will reference this document to describe specific uses. Traffic Engineered (TE) networks have a variety of mechanisms to facilitate the separation of the data plane and control plane. They also have a range of management and provisioning protocols to configure and activate network resources. These mechanisms represent key technologies for enabling flexible and dynamic networking. The term "Traffic Engineered network" refers to a network that uses any connection-oriented technology under the control of a distributed or centralized control plane to support dynamic provisioning of end-to- end connectivity. Abstraction of network resources is a technique that can be applied to a single network domain or across multiple domains to create a single virtualized network that is under the control of a network operator or the customer of the operator that actually owns the network resources. This document provides a framework for Abstraction and Control of TE Networks (ACTN) to support virtual network services and connectivity services. This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.

Examples of the application of the Bandwidth Availability Topology Model This appendix provides some examples and illustrations of how the Bandwidth Availability Topology Model can be used. There is one extended tree to illustrate the model and a JSON based instantiation for a small network example.

A tree for a the Bandwidth Availability Topology Model The tree below shows the leafs for the Bandwidth Availability Model including the augmented Network Topology Model defined in and Traffic Engineering (TE) Topologies model defined in .

A JSON example

Acknowledgments This document was prepared using kramdown The authors would like to thank ...