YANG Data Models for Transport TE FGNM Extension Model

YANG Data Models for Transport TE FGNM Extension Model Huawei Technologies

yuchaode@huawei.com

CAICT

zhaoxing@caict.ac.cn

CCAMP Working Group This document defines two extension YANG data models augmenting to TE topology and TE tunnel YANG model, based on the FGNM (Fine-Grain Network Management) requirements in transport networks.

Introduction defines a YANG data model for technology generic, and it is augmented by some other technology specific data models, e.g. OTN topology data model in {{!draft-ietf-ccamp-otn-topo-yang}}. defines a YANG data model for the provisioning and management of Traffic Engineering (TE) tunnels, Label Switched Paths (LSPs), and interfaces. Similarly, it could be also augmented by some other technology specific data models to implement a specific layer of TE tunnel. According to , it is good to used the current TE data model system to manage an abstracted network topology. In {{!draft-gstk-ccamp-actn-optical-transport-mgmt}}, it is called Abstracted Control (AC) approach. In , it also raised another management approach, which is called Fine-Grain Network Management (FGNM). FGNM is aimed to provide traditional FCAPS capabilities. describes transport network from the viewpoint of the information transfer capability, provides a generic functional architecture which is also implementation independent. This recommendation is the implementation basis of most of the vendors' or operators' systems. To provide traditional FCAPS functionalities, we need to align with the modelling of traditional approach, which is suggested to be . Therefore, some more TMF attributes would be introduced. To avoid introducing non-backward-compatible (NBC) changes, we would like to provide some extension YANG data models, based on the current model architecture. Some extensions is generic for all network layers would be defined in the FGNM extension models, including generic TE topology FGNM extension and generic TE tunnel FGNM extension. The layer specific FGNM extension should be found in some other YANG data models.

Terminology and Notations Refer to and for the key terms used in this document. The following terms are defined in and are not redefined here: * client * server * augment * data model * data node The following terms are defined in and are not redefined here: * configuration data * state data The following terms are defined in and are not redefined here: * CMI * MPI * MDSC * CNC * PNC

Tree Diagram A simplified graphical representation of the data model is used in Section 3 of this document. The meaning of the symbols in these diagrams are defined in .

Prefix in Data Node Names In this document, names of data nodes and other data model objects are prefixed using the standard prefix associated with the corresponding YANG imported models, as showned in the following table. Prefix Yang model Reference nw ietf-network nt ietf-network-topology tet ietf-te-topology yang ietf-yang-types inet ietf-inet-types te-types ietf-te-types te ietf-te RFC YYYY tet-fgnm-ext ietf-te-topology-fgnm-ext RFC XXXX te-fgnm-ext ietf-te-fgnm-ext RFC XXXX te-types-fgnm-ext ietf-te-types-fgnm-ext RFC XXXX RFC Editor Note: Please replace XXXX with the RFC number assigned to this document. Please replace YYYY with the RFC number assigned to the TE tunnel draft. Please remove this note.

Mapping of ACTN modelling Objects with TMF objects {{ITU-T G.805}} describes the network as a transport network from the viewpoint of the information transfer capability. More specifically, the functional and structural architecture of transport networks are described independently of networking technology. It also defines various types of reference points, such as the Access Point (AP), Connection Point (CP), and Trail Connection Point (TCP), and the processing between reference points, which is called adaptation. A transport entity that transmits information such as trails and connections between reference points. For the details, we can refer to descriptions in chapter 3 of {{ITU-T G.805}} and Figure 1 to Figure 3. One disadvantage of {{ITU-T G.805}} is it is too complicated. So TMF simplifies the modelling system of {{ITU-T G.805}}. The adaptation is changed to be the capabilities of reference points. The reference points is so that changed to some other terminologies, e.g. PTP and FTP etc. This simplification still can be mapped to {{ITU-T G.805}}. So that a lot of vendors and operators choose TMF modelling in their system. Based on the TMF modelling, CORBA/XML interface was defined to provide FCAPS interfaces. These interfaces were widely used in the operators’ network. The transport ACTN is also initially designed to simplify network configurations. To have a unified modelling with IP technology, many new modelling terms of TE were introduced and build up a new modelling system. Theoretically, these new modelling objects should be a part of, or can be mapped to the reference points or adaptation defined by {{ITU-T G.805}}. However, in the existing IETF documents, there is not sufficient details can be found. If the transport ACTN interface wants to support the complete FCAPS capability, there could be two approaches. The first approach is the ACTN interface build up a new alarm/performance monitoring mechanism, based on its abstract control modelling. Just like what have been done in {{!ITU-T G.874}} and {{!ITU-T G.875}}. The second approach is reusing the traditional alarm/performance monitoring mechanism, so that the ACTN modelling needs to be mapped to the traditional modelling. Currently, there is not sufficient theoretical support for the first approach, and there is not such a attempt is tried in IETF. For the second approach, one of the advantage is it can inherit the functions integrated before. So that there would not be two much efforts need to pay for the new integration. In this document, we would like to follow the second approach. The following table provides a mapping between the ACTN objects and TMF objects. ACTN Object TMF Object Network NA Node Management Element Link Topology Link TP PTP TTP CTP/FTP Tunnel SNC/XC NE Management Element component equipment holder/equipment Client signal NA Ethernet Client signal NA NA Protection Group NA Equipment Protection Group The ONF TAPI also defines a new set of terms, which are different from the definitions of the {{ITU-T G.805}}. But it provides the mapping of TAPI objects to ITU-T objects in Figure 3-2 of {{ONF_TR-547}}. In the appendix of this document, we also compare the ACTN object modelling and TAPI object modelling, which can be used as a reference for a possible integration of these two interfaces in a same MDSC.

Model Relationship The current ACTN topology models for transport technology follows the relationship as bellow:

TE topology model was aimed to define common attributes for all the technologies. OTN topology and WDM topology, etc., they are all augmenting TE topology model to provide layer-specific extensions. Although most of the objects in ACTN and TMF can be mapped to each other, the parameters of the objects cannot be completely matched. In other words, the current ACTN object needs to be extended with some properties to support the full functionality of a traditional object. But in the traditional transport standards there is not such a saying of TE-related modelling. If we want to extend the current IETF data models to have full modelling of traditional approach, which is called FGNM extension by us, we suggest to define the common attributes for all the technologies in a TE topology FGNM extension model. For layer-specific FGNM extensions could reference existing way and define in a separated layer-specific FGNM extension document. So in the FGNM approach, the ACTN topology architecture will be extended to be:

It is also same for the TE tunnel architecture. The whole architecture after FGNM tunnel extensions will be:

FGNM Topology For the some objects, although it is defined in IETF, but the way of abstraction is not so implementation friendly, especially for TTP.

FGNM extension for TE topology To be added

The Modelling and Usage of TTP According to the description of {{!RFC8795}}, TTP is an element of a TE topology representing one or several potential transport service termination points, (i.e., service client adaptation points, such as a WDM/OCh transponder). In the ITU-T standard, such an adaptation point can be the termination point of an end-to-end connection, or the source or sink point of the intermediate cross-connection. A physical port can generate a lot of logical objects. For example, a 100G line port can function as 80 lower-order ODU0 adaptation points, 40 ODU1 adaptation points, or even the adaptation point of an OCh tunnel. Considering the data volume in large-scale network, it is not wise to expose all these points. Because that most of them are potentially existing, they are probably not used at the end. In the document of TE topology, it is not indicated whether the TTPs should be provided at day 0 or not. And it is also hard to find the correlation with the physical port. In this document, we suggest not to provide the potential TTPs but the existing TTPs who have been used by connections at any time. If the client want to retrieve these potential TTPs, a single RPC can help to do so. This RPC should return the existing and potential TTPs at the same time. The key of TTP is tunnel-tp-id which is a binary type. For the potential TTPs, it is no need to allocate a tunnel-tp-id for them. But the server can provide a name for these TTPs, this name should follow the pattern defined by TMF. When the client want to reference a potential TTP, it can reference the name of this TTP, and then the server will allocated a tunnel-tp-id for it after the connection created. And this TTP is no more than a potential TTP but an existing TTP, it should appear in the TTP list of topology.

FGNM Extensions for TE Tunnel

Modelling of Point to Multi-Points and Multi-Points to Multi-Points TE Tunnel The current TE tunnel model only supports point-to-point scenario. Therefore, only one source and sink structure is defined on the tunnel node. In the transport technology, there are point-to-multipoint scenarios and multipoint-to-multipoint connection scenarios. For example, multicast service. We suggest to extend the current TE tunnel model to support the multi-point scenario. Considering the TTPs was not generate before the tunnel created, the client can reference by the TTP by name.

Restoration

Lock of Restoration In some maintenance scenarios, people may need to freeze the restoration capability of a TE tunnel. For example, after obtaining the customers' consent, the carrier can choose not to restore services during the TE tunnel cutover. This prevents unstable services flapping caused by repeated fiber cuts during the cutover. The unstable services flapping would also affects existing services. Section 3.2.8.11 in {{!ITU-T G.808}} mentions the freezing operation of protection and rerouting switching. Therefore, compared with traditional path management, the current TE tunnel model also needs to add freezing capability to the protection and restoration structure.

Lock of Restoration Reversion For some cutover scenario, services may be rerouted to a new trail before the cutover operation. During the cutover, the fiber may be frequently plug in and plug out due to commissioning. To make sure that the new route will not go back to the original route and if the tunnel is restoration reversion, there would be a requirement the freeze the restoration reversion function. This is also a functionality defined by ITU-T and it's missing in the current TE tunnel.

Scheduling of Reversion Time Maintenance job usually is taken place in a fixed time window, for example at night when people are not using the network frequently as daytime. So that there will not be impact as large as operating at daytime if the maintenance job is failed. Operator can choose to revert the services to the original path at night, so that the restoration reversion would not have big impact on the network.

Priority of Restoration In some operator, they configure different restoration priority to different tunnels or services. When multiple services need to be restored at a same time, high-priority services preferentially occupy resources, and low-priority services can be rerouted only after the rerouting of high-priority services is complete.

YANG for Restoration Extension

TTP Hop The current TE tunnel data model can support to specify explicit node/LTP included/excluded. However, for finer grain object, such as TTP, it is not supported to specify. For example, in the scenario where lower-order and higher-order ODUk tunnel are both existing, sometimes multiple lower-order ODUk tunnels need to multiplex a higher-order ODUk tunnel. The client can specify the higher-order ODUk tunnel's TTP to be included in the lower-order ODUk tunnel's creation request. If the lower-order ODUk doesn't need to multiplex a higher-order ODUk tunnel, the client can specify the higher-order ODUk tunnel's TTP to be excluded in the lower-order ODUk tunnel's creation request. There can be two ways to specify this TTP. This higher-order ODUk TTP can be existing in the topology if it has been occupied by a higher-order ODUk tunnel. Then in the TTP hop, the client can specify the ttp-id of this TTP. This TTP can also be nonexisting in the topology or idle for tunnel creation. And then then client can specify the name of TTP in the creation request.

Tree Diagram

FGNM Extension for TE Topology below shows the tree diagram of the YANG data model defined in model ietf-te-topology-fgnm-ext.yang().

FGNM Extension for TE Tunnel below shows the tree diagram of the YANG data model defined in module ietf-te-fgnm-ext.yang().

YANG Data Model

FGNM Extensin for TE Topology

FGNM Extensin for TE Tunnel

WG List: Editor: Chaode Yu Xing Zhao "; description "This module provide some extensions to TE topology model, based on transport fine-grain network management requirement"; revision 2024-03-04 { description "Revision 1.0"; reference "draft-yu-ccamp-te-fgnm-yang-00"; } augment "/te:te/te:tunnels/te:tunnel" { leaf alias { description "alias of TE tunnel"; type string; } uses time-state-grouping; container source-endpoints { list source-endpoint { uses endpoint-grouping; } } container destination-endpoints { list destination-endpoint { uses endpoint-grouping; } } } augment "/te:te/te:tunnels/te:tunnel/te:restoration" { leaf restoration-lock { description "a lock to control whether the restoration can take effect or not, it is useful in the maintenance scenrios, such as in cutover"; type boolean; } leaf restoration-reversion-lock { description "a lock to control whether the reversion of restoration can take effect or not."; type boolean; } leaf scheduled-reversion-time { description "a time when the reversion of restoration can take effect."; type yang:date-and-time; } leaf restoration-priority { description "when there are multiple services need to be restored, the higher estoration priority services can occupied the idle resource in priority, it is used to control the restoration sequence."; type enumeration { enum high; enum medium; enum low; } } leaf restoration-layer { description "the layer of topolgy prefered to be operated when restoration is needed."; type enumeration { enum odu; enum wdm; } } } augment "/te:te/te:tunnels/te:tunnel/te:primary-paths" + "/te:primary-path/te:explicit-route-objects-always" + "/te:route-object-include-exclude/te:type" { description "a TTP hop"; case ttp-hop { uses te-types-fgnm-ext:explicit-ttp-hop; } } augment "/te:te/te:tunnels/te:tunnel/te:secondary-paths" + "/te:secondary-path/te:explicit-route-objects-always" + "/te:route-object-include-exclude/te:type" { description "a TTP hop"; case ttp-hop { uses te-types-fgnm-ext:explicit-ttp-hop; } } augment "/te:te/te:tunnels/te:tunnel/te:primary-paths" + "/te:primary-path/te:primary-reverse-path" + "/te:explicit-route-objects-always" + "/te:route-object-include-exclude/te:type" { description "a TTP hop"; case ttp-hop { uses te-types-fgnm-ext:explicit-ttp-hop; } } augment "/te:te/te:tunnels/te:tunnel/te:secondary-reverse-paths" + "/te:secondary-reverse-path" + "/te:explicit-route-objects-always" + "/te:route-object-include-exclude/te:type" { description "a TTP hop"; case ttp-hop { uses te-types-fgnm-ext:explicit-ttp-hop; } } grouping time-state-grouping { leaf create-time { config false; description "the time when the tunnel was created"; type yang:date-and-time; } leaf active-time { config false; description "the lastest time when the tunnel was activated"; type yang:date-and-time; } } grouping endpoint-grouping { leaf node-id { type leafref { path "/nw:networks/nw:network/nw:node/nw:node-id"; } } choice endpoint-tp { case ltp { leaf tp-id { type leafref { path "/nw:networks/nw:network/nw:node/nt:termination-point" + "/nt:tp-id"; } } } case ttp { choice id-or-name { case id { leaf ttp-id { type leafref { path "/nw:networks/nw:network/nw:node/tet:te" + "/tet:tunnel-termination-point/tet:tunnel-tp-id"; } } } case name { leaf ttp-name { type leafref { path "/nw:networks/nw:network/nw:node/tet:te" + "/tet:tunnel-termination-point/tet:name"; } } } } } } leaf protection-role { description "role of this endpoint in multipoints scenario"; type enumeration { enum work; enum protect; } } } } ]]>

Manageability Considerations <Add any manageability considerations>

Security Considerations <Add any security considerations>

IANA Considerations <Add any IANA considerations>

The YANG 1.1 Data Modeling Language YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF). Network Configuration Protocol (NETCONF) 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] YANG Tree Diagrams 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. Common YANG Data Types This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021. YANG Data Model for Traffic Engineering (TE) Topologies 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. Routing and Wavelength Assignment Information Encoding for Wavelength Switched Optical Networks A Wavelength Switched Optical Network (WSON) requires certain key information fields be made available to facilitate path computation and the establishment of Label Switched Paths (LSPs). The information model described in "Routing and Wavelength Assignment Information Model for Wavelength Switched Optical Networks" (RFC 7446) shows what information is required at specific points in the WSON. Part of the WSON information model contains aspects that may be of general applicability to other technologies, while other parts are specific to WSONs. This document provides efficient, protocol-agnostic encodings for the WSON-specific information fields. It is intended that protocol- specific documents will reference this memo to describe how information is carried for specific uses. Such encodings can be used to extend GMPLS signaling and routing protocols. In addition, these encodings could be used by other mechanisms to convey this same information to a Path Computation Element (PCE). Information Model for Abstraction and Control of TE Networks (ACTN) This document provides an information model for Abstraction and Control of TE Networks (ACTN). Common YANG Data Types for Traffic Engineering This document defines a collection of common data types and groupings in YANG data modeling language. These derived common types and groupings are intended to be imported by modules that model Traffic Engineering (TE) configuration and state capabilities. Routing and Wavelength Assignment Information Model for Wavelength Switched Optical Networks This document provides a model of information needed by the Routing and Wavelength Assignment (RWA) process in Wavelength Switched Optical Networks (WSONs). The purpose of the information described in this model is to facilitate constrained optical path computation in WSONs. This model takes into account compatibility constraints between WSON signal attributes and network elements but does not include constraints due to optical impairments. Aspects of this information that may be of use to other technologies utilizing a GMPLS control plane are discussed. A YANG Data Model for Network Topologies This document provides an information model for Abstraction and Control of TE Networks (ACTN). Transport Northbound Interface Applicability Statement A YANG Data Model for Traffic Engineering Tunnels, Label Switched Paths and Interfaces Integrating YANG Configuration and Management into an Abstraction and Control of TE Networks (ACTN) System for Optical Networks MTNM Solution Set (IDL) R4.5 TM Forum (TMF) Generic functional architecture of transport networks International Telecommunication Union

Appendix

Mapping Between ACTN & TMF & TAPI Modelling ACTN Object TMF Object TAPI Object Network NA Topology Node Management Element Node Link Topology Link Link TP PTP SIP/NEP TTP CTP/FTP CEP Tunnel SNC/XC Connection NE Management Element Device Component Equipment Holder/Equipment Equipment/Holder Client signal NA Connectivity service Ethernet Client signal NA Connectivity service NA Protection Group NA NA Equipment Protection Group NA

Acknowledgments