docs/ecosystem/architecture/index.rst

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.. Copyright 2017-2018 Huawei Technologies Co., Ltd.
.. Copyright 2019 ONAP Contributors
.. Copyright 2020 ONAP Contributors
.. Copyright 2021 ONAP Contributors
.. Copyright 2022 ONAP Contributors
.. Copyright 2023 ONAP Contributors
.. Copyright 2024 ONAP Contributors

.. _ONAP-architecture:

Architecture
============
ONAP is no longer a platform, rather it provides various network automation
functions, and security reference configuration in LFN.

ONAP provides network automation functions for orchestration, management, and
automation of network and edge computing services for network operators, cloud
providers, and enterprises. Real-time, policy-driven orchestration and
automation of physical, virtual, and cloud native network functions enables
rapid automation of new services and complete lifecycle management critical for
5G and next-generation networks, with Intent-based automation and genAI/ML.

The ONAP project addresses the need for automation functions for
telecommunication, cable, and cloud service providers—and their solution
providers—to deliver differentiated network services on demand, profitably and
competitively, while leveraging existing investments.

The challenge that ONAP meets is to help network operators keep up with the
scale and cost of manual changes required to implement new service offerings,
from installing new data center equipment to, in some cases, upgrading
on-premises customer equipment. Many are seeking to exploit SDN and NFV to
improve service velocity, simplify equipment interoperability and integration,
and to reduce overall CapEx and OpEx costs. In addition, the current, highly
fragmented management landscape makes it difficult to monitor and guarantee
service-level agreements (SLAs).

ONAP is addressing these challenges by developing global and massive scale
(multi-site and multi-VIM) automation capabilities for physical, virtual, and
cloud native network elements. It facilitates service agility by supporting
data models for rapid service and resource deployment and providing a common
set of northbound REST APIs that are open and interoperable, and by supporting
model-driven interfaces to the networks. ONAP’s modular and layered nature
improves interoperability and simplifies integration, allowing it to support
1) multiple VNF environments by integrating with multiple VIMs, VNFMs, SDN
Controllers, as well as legacy equipment (PNF) and 2) Cloud Native environments
by integrating Kubernetes, CNFMs and other controllers. The Service Design &
Creation (SDC) project also offers seamless orchestration of CNFs. ONAP’s
consolidated xNF requirements publication enables commercial development of
ONAP-compliant xNFs. This approach allows network and cloud operators to
optimize their physical, virtual and cloud native infrastructure for cost and
performance; at the same time, ONAP’s use of standard models reduces
integration and deployment costs of heterogeneous equipment. All this is
achieved while minimizing management fragmentation.

The ONAP allows end-user organizations and their network/cloud providers to
collaboratively instantiate network elements and services in a rapid and
dynamic way, together with supporting a closed control loop process that
supports real-time response to actionable events. In order to design, engineer,
plan, bill and assure these dynamic services, there are three major
requirements:

- A robust design framework that allows the specification of the service in all
  aspects – modeling the resources and relationships that make up the service,
  specifying the policy rules that guide the service behavior, specifying the
  applications, analytics and closed control loop events needed for the elastic
  management of the service
- An orchestration and control framework (Service Orchestrator and Controllers)
  that is recipe/ policy-driven to provide an automated instantiation of the
  service when needed and managing service demands in an elastic manner
- An analytic framework that closely monitors the service behavior during the
  service lifecycle based on the specified design, analytics and policies to
  enable response as required from the control framework, to deal with
  situations ranging from those that require healing to those that require
  scaling of the resources to elastically adjust to demand variations.

To achieve this, ONAP decouples the details of specific services and supporting
technologies from the common information models, core orchestration components,
and generic management engines (for discovery, provisioning, assurance etc.).

Furthermore, it marries the speed and style of a DevOps/NetOps approach with
the formal models and processes operators require to introduce new services and
technologies. It leverages cloud-native technologies including Kubernetes to
manage and rapidly deploy the ONAP and related components. This is in
stark contrast to traditional OSS/Management software architectures,
which hardcoded services and technologies, and required lengthy software
development and integration cycles to incorporate changes.

The ONAP enables service/resource independent capabilities for design,
creation and lifecycle management, in accordance with the following
foundational principles:

- Ability to dynamically introduce full service lifecycle orchestration
  (design, provisioning and operation) and service API for new services and
  technologies without the need for new software releases or without
  affecting operations for the existing services
- Scalability and distribution to support a large number of services and large
  networks
- Metadata-driven and policy-driven architecture to ensure flexible and
  automated ways in which capabilities are used and delivered
- The architecture shall enable sourcing best-in-class components
- Common capabilities are ‘developed’ once and ‘used’ many times
- Core capabilities shall support many diverse services and infrastructures

Further, ONAP comes with a functional architecture with component definitions
and interfaces, which provides a force of industry alignment in addition to
the open source code.

Architecture Overview
---------------------

The ONAP architecture consists of a design time and run time functions, as well
as functions for managing ONAP itself.

   Note: Use the interactive features of the below ONAP Architecture Overview.
   Click to enlarge it. Then hover with your mouse over an element in the
   figure for a short description. Click the element to get forwarded to a more
   detailed description.

.. image:: media/onap-architecture-overview-interactive-path.svg
   :width: 800

**Figure 1: Interactive high-level view of the ONAP architecture with its
microservices-based components. Click to enlarge and discover.**

The figure below provides a simplified functional view of the architecture,
which highlights the role of a few key components:

#. ONAP Design time environment provides onboarding services and resources
   into ONAP and designing required services.
#. External API provides northbound interoperability for the ONAP.
#. ONAP Runtime environment provides a model- and policy-driven orchestration
   and control framework for an automated instantiation and configuration of
   services and resources. Multi-VIM/Cloud provides cloud interoperability for
   the ONAP workloads. Analytic framework that closely monitors the service
   behavior handles closed control loop management for handling healing,
   scaling and update dynamically.
#. OOM provides the ability to manage cloud-native installation and deployments
   to Kubernetes-managed cloud environments.
#. ONAP Shared Services provides shared capabilities for ONAP modules. The ONAP
   Optimization Framework (OOF) provides a declarative, policy-driven approach
   for creating and running optimization applications like Homing/Placement,
   and Change Management Scheduling Optimization. The Security Framework uses
   open-source security patterns and tools, such as Istio, Ingress Gateway,
   oauth2-proxy, and Keycloak. This Security Framework makes ONAP secure
   external and inter-component communications, authentication and
   authorization.
   Logging Framework (reference implementation PoC) supports open-source- and
   standard-based logging. It separates application log generation from log
   collection/aggregation/persistence/visualization/analysis; i.e., ONAP
   applications handle log generation only and the Logging Framework stack will
   handle the rest. As a result, operators can leverage/extend their own
   logging stacks.
#. ONAP shared utilities provide utilities for the support of the ONAP
   components.

Microservice BUS (MSB) is obsolete from Montreal release. Its function has
been replaced by Istio Service Mesh, Ingress and IdAM (Keycloak) for secure
internal and external communications and security authentication and
authorization.

Information Model and framework utilities continue to evolve to harmonize
the topology, workflow, and policy models from a number of SDOs including
ETSI NFV MANO, ETSI/3GPP, O-RAN, TM Forum SID, ONF Core, OASIS TOSCA, IETF,
and MEF.

|image2|

**Figure 2. Functional view of the ONAP architecture**

Introduction of ONAP Streamlining evolution
-------------------------------------------
Rationale
^^^^^^^^^
Previously, ONAP as a platform had shown e2e network automation to the
industry. Operators, vendors and enterprises have learned how service/network
automation (modeling, orchestration, policy-based closed loop, optimization,
etc.) works on VM and Cloud-native environments for VNF, PNF, CNF, NS,
Network/RAN slicing and e2e service thru ONAP.
In ONAP, there are numerous valuable use cases, that leverage and coordinate
clusters of ONAP component functions (e.g., SDC, SO, A&AI, DCAE, SDNC, SDNR,
CPS, CDS...) to achieve objectives, such as:

- E2E Service
- Network Slicing
- RAN Slicing
- Closed Loop
- ETSI-based NS & VNF orchestration
- Helm-based CNF orchestration
- ASD-based (including Helm) CNF orchestration

Now, the operators, vendors and enterprises want to select and apply ONAP
functions to their portfolio. No one needs to take ONAP as a whole.

Goal
^^^^
The goal is to continue to support the current ONAP use cases efficiently for
use in commercial production environments and portfolio. We expect the industry
wants to pick and choose desired ONAP component functions, swap some of the
ONAP functions, and integrate those functions into their portfolio seamlessly,
without bringing in a whole ONAP platform.
ONAP Streamlining, which drives individual components and clusters of
components guided by use cases, will enable the flexible and dynamic function
adoption by the industry

ONAP Streamlining Transformation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Thru ONAP Streamlining, ONAP is no longer a platform, rather it provides
various network automation functions, and security reference configuration in
LFN. ONAP enables individual ONAP function build, and component deployment
thru CD. It will build use cases for repository-based E2E service, NS, CNF and
CNA onboarding, and CD-based ONAP component triggering mechanism with
abstracted interfaces for choreography. It will boost standard-based abstracted
interfaces with declarative APIs, i.e., each component will be autonomous and
invoked from any level of network automation, by leveraging CD mechanisms, such
as GitOps and CD readiness.

ONAP will become more intent-based and declarative, and bring in genAI/ML,
conforming to standards such as 3GPP, TMForum, ETSI, IETF, O-RAN, etc. For
example, UUI user intent support and AI-based natural language translation, on
top of that, applying coming 3GPP and TMForum models and APIs. Also, it will
delegate resource-level orchestration to functions from the external community,
such as O-RAN SC and Nephio.

For security, ONAP continues to support the Service Mesh, Ingress, OAuth2,
IdAM-based authentication and authorization, and considers sidecar-less
solutions for NF security.

|image3|

**Figure 3. ONAP Streamlining evolution**

ONAP Component Design Requirements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- ONAP components should be designed not only for ONAP but also non-ONAP
  consumption.
- ONAP component dependencies and couplings to other ONAP components should
  not be in an ONAP-specific way.
- Making each ONAP component should be 'stand-alone', so potential users can
  take a single component, without getting involved in the whole of ONAP.
- ONAP component interactions should be based on standards and extensible to
  facilitate integration with other systems, especially for non-ONAP.
- ONAP component Helm charts in OOM should be re-written to build/deploy a
  component individually.
- ONAP Security mechanisms should be industry standard/de facto-based to
  integrate with vendor/operator security and logging.
- Timelines and cadence of the ONAP release should be flexible for
  accommodating different release strategies.

ONAP Component Design, Build & Deployment
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ONAP components are independently deployable pieces of software, built out of
one more microservices:
- Modular
- Autonomous
- Extensible and substitutional

ONAP Network Automation processes will manage more intent-based operations
using AI/ML.
- Manage use and other intents and translations
- Study on TMForum and 3GPP intent models and APIs

ONAP components conform to the standards and de facto specifications to enable
plug- and-play and pick-and-choose facilitation.

ONAP repository-based SW management enables smaller imperative actions that
can be triggered by different events in the orchestration and SW LCM flow.
Events can trigger different types of deployment automation jobs or chains of
automation jobs (pipelines).

In Jenkins ONAP OOM build scripts will be used for ONAP component builds and
will store built ONAP components into the Artifact Repository (e.g., Nexus).
This can be changed. CD (e.g., ArgoCD, Flux, others) will be used to
pick-and-choose ONAP components.

|image4|

**Figure 4. ONAP Streamlining Component Build and Deployment**

For more details of ONAP streamlining, see the ONAP Streamlining - The Process
page, https://wiki.onap.org/display/DW/ONAP+Streamlining+-+The+Process

Microservices Support
---------------------
As a cloud-native application that consists of numerous services, ONAP requires
sophisticated initial deployment as well as post- deployment management.

ONAP is no longer a platform, rather it provides network automation functions,
and security reference configuration in LFN.

Thru ONAP Streamlining evolution, the ONAP deployment methodology has been
enhanced, allowing individual ONAP components can be picked up through a chosen
CD (Continuous Deployment) tool. This enhancement should be flexible enough to
suit the different scenarios and purposes for various operator environments.
Users may also want to select a portion of the ONAP components to integrate
into their own systems. For more details of ONAP Streamlining evolution, see
the ONAP Streamlining evolution session.

The provided ONAP functions are highly reliable, scalable, extensible, secure
and easy to manage. To achieve all these goals, ONAP is designed as a
microservices-based system, with all components released as Docker containers
following best practice building rules to optimize their image size. Numerous
optimizations such as shared databases and the use of standardized lightweight
container operating systems reduce the overall ONAP footprint.

In the spirit of leveraging the microservice capabilities, further steps
towards increased modularity have been taken. Service Orchestrator (SO) and the
controllers have increased its level of modularity, by following Microservices.

ONAP Operations Manager (OOM)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The ONAP Operations Manager (OOM) is responsible for orchestrating the
end-to-end lifecycle management and monitoring of ONAP components. OOM uses
Kubernetes with IPv4 and IPv6 support to provide CPU efficiency and ONAP
component deployment. In addition, OOM helps enhance ONAP maturity by providing
scalability and resiliency enhancements to the components it manages.

OOM is the lifecycle manager of the ONAP and uses the Kubernetes
container management system and Consul to provide the following functionality:

#. Deployment - with built-in component dependency management (including
   multiple clusters, federated deployments across sites, and anti-affinity
   rules)
#. Configuration - unified configuration across all ONAP components
#. Monitoring - real-time health monitoring feeding to a Consul GUI and
   Kubernetes
#. Restart - failed ONAP components are restarted automatically
#. Clustering and Scaling - cluster ONAP services to enable seamless scaling
#. Upgrade - change out containers or configuration with little or no service
   impact
#. Deletion - clean up individual containers or entire deployments

OOM supports a wide variety of cloud infrastructures to suit your individual
requirements.

OOM provides Service Mesh-based mTLS (mutual TLS) between ONAP components to
secure component communications, by leveraging Istio.

In addition to Service Mesh-based mTLS, OOM also provides inter-component
authentication and authorization, by leveraging Istio Authorizaiton Policy.
For external secure communication, authentication (including SSO) and
authorization, OOM configures Ingress, oauth2-proxy, IAM (realized by
KeyCloak) and IdP.

As the result, Unmaintained AAF functionalities are obsolete and substituted
by Istio-based Service Mesh and Ingress, as of Montreal release.

|image5|

**Figure 5. Security Framework component architecture**

For OOM enhancements for ONAP Streamlining evolution, see the ONAP Streamlining
evolution section.

Microservices Bus (MSB)
^^^^^^^^^^^^^^^^^^^^^^^

.. warning:: The ONAP :strong:`MSB` project is :strong:`deprecated`.
             As of Release 13 'Montreal' the component is no longer part of the
             ONAP deployment.

Microservices Bus (MSB) used to support service registration/ discovery,
external API gateway, internal API gateway, client software development
kit (SDK), and Swagger SDK. When integrating with OOM, MSB used to have
a Kube2MSB registrar which can grasp services information from k8s metafile
and automatically register the services for ONAP components.

In London release, ONAP Security Framework components provide secure
communication capabilities. This approach is a more Kubernetes-native approach.
As a result, MSB functions has been replaced by the Security Framework, and MSB
becomes an optional component.

Portal-NG
---------
ONAP had a portal project but this project was terminated and archived.
Portal-NG is a new component and fills the gap. It provides a state of the art
web-based GUI that services as the first discovery point for the ONAP, its
existing web applications and functions.
Onboard users with an adaptive GUI following a "grow as you go" approach
covering "playful discovery" up to expert mode. Wherever possible hide
complexity of network automation by guiding the user.
The Portal-NG supports new ONAP Security framework for user administration,
authentication and authorization. For more details, see the Portal-NG section.

Design Time Components
----------------------
The design time components are a comprehensive development environment with
tools, techniques, and repositories for defining/ describing resources,
services, and products.

The design time components facilitate reuse of models, further improving
efficiency as more and more models become available. Resources, services,
products, and their management and control functions can all be modeled using a
common set of specifications and policies (e.g., rule sets) for controlling
behavior and process execution. Process specifications automatically sequence
instantiation, delivery and lifecycle management for resources, services,
products and the ONAP components themselves. Certain process specifications
(i.e., ‘recipes’) and policies are geographically distributed to optimize
performance and maximize autonomous behavior in federated cloud environments.

Service Design and Creation (SDC)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Service Design and Creation (SDC) provides tools, techniques, and repositories
to define/simulate/certify system assets as well as their associated processes
and policies. Each asset is categorized into one of four asset groups: Resource
, Services, Products, or Offers. SDC supports the onboarding of Network
Services packages (ETSI SOL007 with ETSI SOL001), ONAP proprietary CNF packages
(embedding Helm Chart), ASD-based CNF packages (ETSI SOL004 and embedding Helm
Chart), VNF packages (Heat or ETSI SOL004) and PNF packages (ETSI SOL004). SDC
also includes some capabilities to model 5G network slicing using the standard
properties (Slice Profile, Service Template).

Since Kohn-R11 release, SDC supports the onboarding of another CNF-Modeling
package, Application Service Description (ASD) package. ASD is a deployment
descriptor for cloud native applications/functions. It minimizes information
needed for the CNF orchestrator, by referencing most resource descriptions to
the cloud native artifacts (e.g., Helm Chart). Its CSAR package adheres to
ETSI SOL004.

The SDC environment supports diverse users via common services and utilities.
Using the design studio, product and service designers onboard/extend/retire
resources, services and products. Operations, Engineers, Customer Experience
Managers, and Security Experts create workflows, policies and methods to
implement Closed Control Loop Automation/Control and manage elastic
scalability.

Vendors can integrate these tools in their CI/CD environments to package VNFs
and upload them to the validation engine. Once tested, the VNFs can be onboarded
through SDC. ONAP supports onboarding of CNFs and PNFs as well.

The Policy Creation component deals with policies; these are rules, conditions,
requirements, constraints, attributes, or needs that must be provided,
maintained, and/or enforced. At a lower level, Policy involves machine-readable
rules enabling actions to be taken based on triggers or requests. Policies
often consider specific conditions in effect (both in terms of triggering
specific policies when conditions are met, and in selecting specific outcomes
of the evaluated policies appropriate to the conditions).

Policy allows rapid modification through easily updating rules, thus updating
technical behaviors of components in which those policies are used, without
requiring rewrites of their software code. Policy permits simpler
management / control of complex mechanisms via abstraction.

VNF SDK
^^^^^^^

.. warning:: The ONAP :strong: 'VNF SDK' project is :strong:'deprecated'.

VNF SDK provides the functionality to create VNF/PNF packages, test VNF
packages and VNF ONAP compliance and store VNF/PNF packages and upload to/from
a marketplace.

VVP
^^^

.. warning:: The ONAP :strong: 'VVP' project is :strong:'deprecated'.

VVP provides validation for the VNF Heat package.

Runtime Components
------------------
The runtime execution components execute the rules and policies and other
models distributed by the design and creation environment.

This allows for the distribution of models and policy among various ONAP
modules such as the Service Orchestrator (SO), Controllers, Data Collection,
Analytics and Events (DCAE), Active and Available Inventory (A&AI). These
components use common services that support security (access control,
secure communication), logging and configuration data.

Orchestration
^^^^^^^^^^^^^
The Service Orchestrator (SO) component executes the specified processes by
automating sequences of activities, tasks, rules and policies needed for
on-demand creation, modification or removal of network, application or
infrastructure services and resources, this includes VNFs, CNFs and PNFs,
by conforming to industry standards such as ETSI, TMF, 3GPP.
The SO provides orchestration at a very high level, with an end-to-end view
of the infrastructure, network, and applications. Examples of this include
BroadBand Service (BBS) and Cross Domain and Cross Layer VPN (CCVPN).
The SO is modular and hierarchical to handle services and multi-level
resources and Network Slicing, by leveraging pluggable adapters and delegating
orchestration operations to NFVO (SO NFVO, VFC), VNFM, CNF Manager, NSMF
(Network Slice Management Function), NSSMF (Network Slice Subnet Management
Function).

Starting from the Guilin release, the SO provides CNF orchestration support
through integration of CNF adapter and other CNF managers in ONAP. SO:

- Support for provisioning CNFs using an external K8S Manager
- Support the Helm-based orchestration
- Leverage the CNF Adapter to interact with the K8S Plugin in MultiCloud, or
  leverage the CNF Manager to interact with the K8S to control CNFs (e.g., ASD)
- Bring in the advantage of the K8S orchestrator and
- Set stage for the Cloud Native scenarios

In London, ONAP SO added ASD-based CNF orchestration support to simplify
CNF orchestration and to remove redundancies of CNF resource attributes and
orchestration process.

- Support for onboarding of ASD-based CNF models and packages in runtime
- Support the SO sub-component 'SO CNFM' for ASD-dedicated CNF orchestration
  to isolate ASD management from other SO components - separation of concerns
- Use of ASD for AS LCM, and use of associated Helm Charts for CNF deployment
  to the selected external K8s Clusters
- Use of Helm Client to communicate with external K8S clusters for CNF
  deployment
- Monitoring deployed K8S resources thru Kubernetes APIs

3GPP (TS 28.801) defines three layer slice management function which include:

- CSMF (Communication Service Management Function)
- NSMF (Network Slice Management Function)
- NSSMF (Network Slice Subnet Management Function)

To realize the three layers, CSMF, NSMF and/or NSSMF are realized within ONAP,
or use the external CSMF, NSMF or NSSMF. For ONAP-based network slice
management, different choices can be made as follows. Among them, ONAP
orchestration currently supports options #1 and #4.

|image6|

**Figure 6: ONAP Network Slicing Support Options**


Virtual Infrastructure Deployment (VID) - obsolete
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. warning:: The ONAP :strong:`vid` project is :strong:`deprecated`.
             As of Release 12 'London' the component is no longer part of the
             ONAP deployment.

The Virtual Infrastructure Deployment (VID) application enables users to
instantiate infrastructure services from SDC, along with their associated
components, and to execute change management operations such as scaling and
software upgrades to existing VNF instances.

Policy-Driven Workload Optimization
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. warning:: The ONAP :strong:'OOF' project is :strong:'deprecated'.

The ONAP Optimization Framework (OOF) provides a policy-driven and model-driven
framework for creating optimization applications for a broad range of use
cases. OOF Homing and Allocation Service (HAS) is a policy driven workload
optimization service that enables optimized placement of services across
multiple sites and multiple clouds, based on a wide variety of policy
constraints including capacity, location, other service capabilities and
constraints.

ONAP Multi-VIM/Cloud (MC) and several other ONAP components such as Policy, SO,
A&AI etc. play an important role in enabling “Policy-driven Performance/
Security-Aware Adaptive Workload Placement/ Scheduling” across cloud sites
through OOF-HAS. OOF-HAS uses cloud agnostic Intent capabilities, and real-time
capacity checks provided by ONAP MC to determine the optimal VIM/Cloud
instances, which can deliver the required performance SLAs, for workload
(VNF, etc.) placement and scheduling (Homing). Operators now realize the true
value of virtualization through fine grained optimization of cloud resources
while delivering performance and security SLAs.

Controllers
^^^^^^^^^^^
Controllers are applications which are coupled with cloud and network services
and execute the configuration, real-time policies, and control the state of
distributed components and services. Rather than using a single monolithic
control layer, operators may choose to use multiple distinct controller types
that manage resources in the execution environment corresponding to their
assigned controlled domain such as cloud computing resources (SDN-C).
The Virtual Function Controller (VF-C) and SO NFVO provide an ETSI NFV
compliant NFVO function that is responsible for lifecycle management of
virtual services and the associated physical COTS server infrastructure. VF-C
provides a generic VNFM capability, and both VF-C and SO NFVO integrate with
external VNFMs and VIMs as part of an NFV MANO stack.

.. warning:: The ONAP :strong:`appc` project is :strong:`deprecated`.
             As of Release 12 'London' the component is no longer part of the
             ONAP deployment.
.. warning:: The ONAP :strong:'VF-C' project is :strong:'deprecated'.

ONAP used to have two application level configuration and lifecycle management
modules called SDN-C and App-C. App-C is no longer part of ONAP deployment.
SDN-C provides controller services (application level configuration using
NetConf, Chef, Ansible, RestConf, etc.) and lifecycle management functions
(e.g., stop, resume, health check, etc.).
SDN-C uses common code from CCSDK repo, and it uses CDS only for onboarding and
configuration / LCM flow design.
SDN-C has been used for Layer1-7 network elements. ONAP Controller configures
and maintains the health of L1-7 Network Function (VNF, PNF, CNF) and network
services throughout their lifecycle:

- Configures Network Functions (VNF/PNF)
- Provides programmable network application management:

  - Behavior patterns programmed via models and policies
  - Standards based models & protocols for multi-vendor implementation
  - Extensible SB adapters such as Netconf, Ansible, Rest API, etc.
  - Operation control, version management, software updates, etc.
- Local source of truth
  - Manages inventory within its scope
  - Manages and stores state of NFs
  - Supports Configuration Audits

Controller Design Studio (CDS)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The Controller Design Studio (CDS) community in ONAP has contributed a
framework to automate the resolution of resources for instantiation and any
config provisioning operation, such as day0, day1 or day2 configuration. The
essential function of CDS is to create and populate a controller blueprint,
create a configuration file from this Controller blueprint, and associate at
design time this configuration file (configlet) to a PNF/VNF/CNF during the
design phase. CDS removes dependence on code releases and the delays they cause
and puts the control of services into the hands of the service providers. Users
can change a model and its parameters with great flexibility to fetch data from
external systems (e.g., IPAM) that is required in real deployments. This makes
service providers more responsive to their customers and able to deliver
products that more closely match the needs of those customers.

Inventory
^^^^^^^^^
Active and Available Inventory (A&AI) provides real-time views of a system’s
resources, services, products and their relationships with each other, and also
retains a historical view. The views provided by A&AI relate data managed by
multiple ONAP instances, Business Support Systems (BSS), Operation Support
Systems (OSS), and network applications to form a “top to bottom” view ranging
from the products end users buy, to the resources that form the raw material
for creating the products. A&AI not only forms a registry of products,
services, and resources, it also maintains up-to-date views of the
relationships between these inventory items.

To deliver the promised dynamism of SDN/NFV, A&AI is updated in real time by
the controllers as they make changes in the network environment. A&AI is
metadata-driven, allowing new inventory types to be added dynamically and
quickly via SDC catalog definitions, eliminating the need for lengthy
development cycles.

Multi Cloud Adaptation
^^^^^^^^^^^^^^^^^^^^^^
Multi-VIM/Cloud provides and infrastructure adaptation layer for VIMs/Clouds
and K8s clusters in exposing advanced cloud agnostic intent capabilities,
besides standard capabilities, which are used by OOF and other components
for enhanced cloud selection and SO/VF-C for cloud agnostic workload
deployment. The K8s plugin is in charge of deploying CNFs on the Kubernetes
clusters using Kubernetes APIs.

Data Collection Analytics and Events (DCAE)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
DCAE provides the capability to collect events, and host analytics applications
(DCAE Services). It gathers performance, usage, and configuration data from
the managed environment. Data is fed to various analytic applications, and if
anomalies or significant events are detected, the results trigger appropriate
actions, such as publishing to other ONAP components such as Policy, SO, or
Controllers.

- Collect, ingest, transform and store data as necessary for analysis
- Provide a framework for development of analytics

Policy Framework
^^^^^^^^^^^^^^^^
The Policy framework is a comprehensive policy design, deployment,
and execution environment. The Policy Framework is the decision making
comopnent in an ONAP system. It allows to specify, deploy, and execute
the governance of the features and functions in ONAP system, support
the closed loop, orchestration, or more traditional open loop use case
implementations.

Since the Istanbul release, the CLAMP is officially integrated into the
Policy component. CLAMP's functional role to provision Policy has been
enhanced to support provisioning of policies outside of the context of
a Control Loop and therefore act as a Policy UI. For CLAMP details, see
the Policy - CLAMP section.

It supports multiple policy engines and can distribute policies through policy
design capabilities in SDC, simplifying the design process.

Closed Control Loop Automation Management Platform in Policy (Policy - CLAMP)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. warning:: The ONAP :strong:`CLAMP` function is now part of :strong:`Policy`.

Closed loop control is provided by cooperation among a number of design-time
and run-time elements. The Runtime loop starts with data collectors from Data
Collection, Analytics and Events (DCAE). ONAP includes the following collectors
: VES (VNF Event Streaming) for events, HV-VES for high-volume events, SNMP
for SNMP traps, File Collector to receive files, and RESTCONF Collector to
collect the notifications. After data collection/verification phase, data move
through the loop of micro-services like Homes for event detection, Policy
for determining actions, and finally, controllers and orchestrators to
implement actions. The Policy framework is also used to monitor the loops
themselves and manage their lifecycle. DCAE also includes a number of
specialized micro-services to support some use-cases such as the Slice Analysis
or SON-Handler. Some dedicated event processor modules transform collected data
(SNMP, 3GPP XML, RESTCONF) to VES format and push the various data into data
lake. CLAMP, Policy and DCAE all have design time aspects to support the
creation of the loops.

We refer to this automation pattern as “Closed Control loop automation” in that
it provides the necessary automation to proactively respond to network and
service conditions without human intervention. A high-level schematic of the
“Closed control loop automation” and the various phases within the service
lifecycle using the automation is depicted in Figure 4.

Closed control loop control is provided by Data Collection, Analytics and
Events (DCAE) and one or more of the other ONAP runtime components.
Collectively, they provide FCAPS (Fault Configuration Accounting Performance
Security) functionality. DCAE collects performance, usage, and configuration
data; provides computation of analytics; aids in troubleshooting; and publishes
events, data and analytics (e.g., to policy, orchestration, and the data lake).
Another component, Holmes, connects to DCAE and provides alarm correlation
for ONAP, new data collection capabilities with High Volume VES, and bulk
performance management support.

Working with the Policy Framework (and embedded CLAMP), these components
detect problems in the network and identify the appropriate remediation.
In some cases, the action will be automatic, and they will notify the
Service Orchestrator or one of the controllers to take action.
In other cases, as configured by the operator, they will raise an alarm
but require human intervention before executing the change. The policy
framework is extended to support additional policy decision capabilities
with the introduction of adaptive policy execution.

Starting with the Honolulu-R8 and concluding in the Istanbul-R9 release, the
CLAMP component was successfully integrated into the Policy component initially
as a PoC in the Honolulu-R8 release and then as a fully integrated component
within the Policy component in Istanbul-R9 release.
CLAMP's functional role to provision Policy has been enhanced to support
provisioning of policies outside of the context of a Control Loop and therefore
act as a Policy UI. In the Istanbul release the CLAMP integration was
officially released.

|image7|

**Figure 7: ONAP Closed Control Loop Automation**

Virtual Function Controller (VFC)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 .. warning:: The ONAP :strong:'VFC' project is :strong:'deprecated'.

VFC provides the NFVO capability to manage the lifecycle of network service and
VNFs, by conforming to ETSI NFV specification.

Data Movement as a Platform (DMaaP)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 .. warning:: The ONAP :strong:'DMaaP MR' project is :strong:'deprecated'.

DMaaP provides data movement services that transports and process data from
any source to any target. Its message routing is deprecated in New Delhi release
and replaced by Strimzi and Kafka. The data routing is still part of New
Delhi release, but it will be deprecated in Oslo release.

Use Case UI (UUI)
^^^^^^^^^^^^^^^^^
UUI provides the capability to instantiate the blueprint User Cases and
visualize the state. UUI is an application portal which provides the ability
to manage ONAP service instances. It allows customers to create/delete/update
service instances, as well as monitoring, alarms and performance of
these instances.

The component supports the following functionalities:
- Customer Management
- Package Management (including IBN packages)
- Service Management (including CCVPN, 5G Slicing, Intent-based automation)
- Network Topology

UUI contains the following sub-components:
- UUI GUI
- UUI Server
- UUI NLP Server (since Istanbul release)
- UUI INTENT ANALYSIS server (since Kohn release)

See UUI Component Architecture,

|image8|

**Figure 8. UUI Component Architecture**

CLI
^^^

.. warning:: The ONAP :strong:'CLI' project is :strong:'deprecated'.

ONAP CLI provides a command line interface for access to ONAP.

External APIs
^^^^^^^^^^^^^

.. warning:: The ONAP :strong:`externalapi` project is :strong:`unmaintained`.

External APIs provide services to expose the capability of ONAP.

Shared Services
---------------

.. warning:: The ONAP :strong:'Logging Framework' project is a reference
   implementation PoC.

ONAP provides a set of operational services for all ONAP components including
activity logging, reporting, common data layer, configuration, persistence,
access control, secret and credential management, resiliency, and software
lifecycle management.

ONAP Shared Services provide shared capabilities for ONAP modules. These
services handle access management and security enforcement, data backup,
configuration persistence, restoration and recovery. They support standardized
VNF interfaces and guidelines.

Optimization Framework (OOF)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. warning:: The ONAP :strong:'OOF' project is :strong:'deprecated'.

OOF provides a declarative, policy-driven approach for creating and running
optimization applications like Homing/Placement, and Change Management
Scheduling Optimization.

Security Framework
^^^^^^^^^^^^^^^^^^
The Security Framework uses open-source security patterns and tools, such as
Istio, Ingress Gateway, oauth2-proxy, and KeyCloak. This Security Framework
provides secure external and inter-component communications, authentication,
and authorization.

For more details, see the Figure 5.

Logging Framework (PoC)
^^^^^^^^^^^^^^^^^^^^^^^

.. warning:: The ONAP :strong:`Logging Framework` project is a reference
   implementation :strong:`PoC`.

Logging Framework supports open-source and standard-based logging. It separates
the application log generation from the log collection/aggregation/persistence/
visualization/analysis; i.e., ONAP applications handle log generation only, and
the Logging Framework stack will handle the rest. As a result, operators can
leverage/extend their own logging stacks.

Configuration Persistence Service (CPS)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The Configuration Persistence Service (CPS) provides storage for real-time
run-time configuration and operational parameters that need to be used by ONAP.
Several services ranging from SDN-C, DCAE and the network slicing use case
utilize CPS for these purposes. In Montreal release, a CPS sub-component CPS-
Temporal is removed because its function is no longer needed.
Its details in :ref:`CPS - Configuration Persistence Service<onap-cps:architecture>`.

ONAP Modeling
-------------

.. warning:: The ONAP :strong:'ONAP Modeling' project is :strong:'deprecated'.

ONAP provides models to assist with service design, the development of ONAP
service components, and with the improvement of standards interoperability.
Models are an essential part for the design time and runtime framework
development. The ONAP modeling project leverages the experience of member
companies, standard organizations and other open source projects to produce
models which are simple, extensible, and reusable. The goal is to fulfill the
requirements of various use cases, guide the development and bring consistency
among ONAP components and explore a common model to improve the
interoperability of ONAP.

ONAP supports various models detailed in the Modeling documentation.

A new CNF modeling descriptor, Application Service Description (ASD), has been
added to ONAP since the Kohn release. It is to simplify CNF modeling and
orchestration by delegating resource modeling to Kubernetes-based resource
descriptors (e.g., Helm Chart).

The modeling project includes the ETSI catalog component, which provides the
parser functionalities, as well as additional package management
functionalities.

Industry Alignment
------------------
ONAP support and collaboration with other standards and open source communities
is evident in the architecture.

- MEF and TMF interfaces are used in the External APIs
- In addition to the ETSI-NFV defined VNFD and NSD models mentioned above, ONAP
  supports the NFVO interfaces (SOL005 between the SO and VFC, SOL003 from
  either the SO or VFC to an external VNFM).
- Further collaboration includes 5G/ORAN & 3GPP Harmonization, Acumos DCAE
  Integration, and CNCF Telecom User Group (TUG).

Read this whitepaper for more information:
`The Progress of ONAP: Harmonizing Open Source and Standards <https://www.onap.org/wp-content/uploads/sites/20/2019/04/ONAP_HarmonizingOpenSourceStandards_032719.pdf>`_

ONAP Blueprints
---------------
ONAP can support an unlimited number of use cases, within reason. However, to
provide concrete examples of how to use ONAP to solve real-world problems, the
community has created a set of blueprints. In addition to helping users rapidly
adopt the ONAP through end-to-end solutions, these blueprints also
help the community prioritize their work.

5G Blueprint
^^^^^^^^^^^^
The 5G blueprint is a multi-release effort, with five key initiatives around
end-to-end service orchestration, network slicing, PNF/VNF lifecycle management
, PNF integration, and network optimization. The combination of eMBB that
promises peak data rates of 20 Mbps, uRLLC that guarantees sub-millisecond
response times, MMTC that can support 0.92 devices per sq. ft., and network
slicing brings with it some unique requirements. First ONAP needs to manage the
lifecycle of a network slice from initial creation/activation all the way to
deactivation/termination. Next, ONAP needs to optimize the network around real
time and bulk analytics, place VNFs on the correct edge cloud, scale and heal
services, and provide edge automation. ONAP also provides self organizing
network (SON) services such as physical cell ID allocation for new RAN sites.
These requirements have led to the five above-listed initiatives and have been
developed in close cooperation with other standards and open source
organizations such as 3GPP, TM Forum, ETSI, and O-RAN Software Community.

|image9|

**Figure 9. End-to-end 5G Service**

Read the `5G Blueprint <https://www.onap.org/wp-content/uploads/sites/20/2019/07/ONAP_CaseSolution_5G_062519.pdf>`_
to learn more.

A related activity outside of ONAP is called the 5G Super Blueprint where
multiple Linux Foundation projects are collaborating to demonstrate an
end-to-end 5G network. In the short-term, this blueprint will showcase
three major projects: ONAP, Anuket (K8S NFVI), and Magma (LTE/5GC).

|image10|

**Figure 10. 5G Super Blueprint Initial Integration Activity**

In the long-term, the 5G Super Blueprint will integrate O-RAN-SC and LF Edge
projects as well.

Residential Connectivity Blueprints
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Two ONAP blueprints (vCPE and BBS) address the residential connectivity use
case.

Virtual CPE (vCPE)
""""""""""""""""""
Currently, services offered to a subscriber are restricted to what is designed
into the broadband residential gateway. In the blueprint, the customer has a
slimmed down physical CPE (pCPE) attached to a traditional broadband network
such as DSL, DOCSIS, or PON (Figure 6). A tunnel is established to a data
center hosting various VNFs providing a much larger set of services to the
subscriber at a significantly lower cost to the operator. In this blueprint,
ONAP supports complex orchestration and management of open source VNFs and both
virtual and underlay connectivity.

|image11|

**Figure 11. ONAP vCPE Architecture**

Read the `Residential vCPE Use Case with ONAP blueprint <https://www.onap.org/wp-content/uploads/sites/20/2018/11/ONAP_CaseSolution_vCPE_112918FNL.pdf>`_
to learn more.

Broadband Service (BBS)
"""""""""""""""""""""""
This blueprint provides multi-gigabit residential internet connectivity
services based on PON (Passive Optical Network) access technology. A key
element of this blueprint is to show automatic re-registration of an ONT
(Optical Network Terminal) once the subscriber moves (nomadic ONT) as well as
service subscription plan changes. This blueprint uses ONAP for the design,
deployment, lifecycle management, and service assurance of broadband services.
It further shows how ONAP can orchestrate services across different locations
(e.g. Central Office, Core) and technology domains (e.g. Access, Edge).

|image12|

**Figure 12. ONAP BBS Architecture**

Read the `Residential Connectivity Blueprint <https://www.onap.org/wp-content/uploads/sites/20/2019/07/ONAP_CaseSolution_BBS_062519.pdf>`_
to learn more.

Voice over LTE (VoLTE) Blueprint
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This blueprint uses ONAP to orchestrate a Voice over LTE service. The VoLTE
blueprint incorporates commercial VNFs to create and manage the underlying
vEPC and vIMS services by interworking with vendor-specific components,
including VNFMs, EMSs, VIMs and SDN controllers, across Edge Data Centers and
a Core Data Center. ONAP supports the VoLTE use case with several key
components: SO, VF-C, SDN-C, and Multi-VIM/ Cloud. In this blueprint, SO is
responsible for VoLTE end-to-end service orchestration working in collaboration
with VF-C and SDN-C. SDN-C establishes network connectivity, then the VF-C
component completes the Network Services and VNF lifecycle management
(including service initiation, termination and manual scaling) and FCAPS
(fault, configuration, accounting, performance, security) management. This
blueprint also shows advanced functionality such as scaling and change
management.

|image13|

**Figure 13. ONAP VoLTE Architecture Open Network Automation**

Read the `VoLTE Blueprint <https://www.onap.org/wp-content/uploads/sites/20/2018/11/ONAP_CaseSolution_VoLTE_112918FNL.pdf>`_
to learn more.

Optical Transport Networking (OTN)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Two ONAP blueprints (CCVPN and MDONS) address the OTN use case. CCVPN addresses
Layers 2 and 3, while MDONS addresses Layers 0 and 1.

CCVPN (Cross Domain and Cross Layer VPN) Blueprint
""""""""""""""""""""""""""""""""""""""""""""""""""
CSPs, such as CMCC and Vodafone, see a strong demand for high-bandwidth, flat,
high-speed OTN (Optical Transport Networks) across carrier networks. They also
want to provide a high-speed, flexible and intelligent service for high-value
customers, and an instant and flexible VPN service for SMB companies.

|image14|

**Figure 14. ONAP CCVPN Architecture**

The CCVPN (Cross Domain and Cross Layer VPN) blueprint is a combination of SOTN
(Super high-speed Optical Transport Network) and ONAP, which takes advantage of
the orchestration ability of ONAP, to realize a unified management and
scheduling of resources and services. It achieves cross-domain orchestration
and ONAP peering across service providers. In this blueprint, SO is responsible
for CCVPN end-to-end service orchestration working in collaboration with VF-C
and SDN-C. SDN-C establishes network connectivity, then the VF-C component
completes the Network Services and VNF lifecycle management. ONAP peering
across CSPs uses an east-west API which is being aligned with the MEF Interlude
API. CCVPN, in conjunction with the IBN use case, offers intent based cloud
leased line service. The key innovations in this use case are physical network
discovery and modeling, cross-domain orchestration across multiple physical
networks, cross operator end-to-end service provisioning, close-loop reroute
for cross-domain service, dynamic changes (branch sites, VNFs) and intelligent
service optimization (including AI/ML).

Read the `CCVPN Blueprint <https://www.onap.org/wp-content/uploads/sites/20/2019/07/ONAP_CaseSolution_CCVPN_062519.pdf>`_
to learn more.

MDONS (Multi-Domain Optical Network Service) Blueprint
""""""""""""""""""""""""""""""""""""""""""""""""""""""
While CCVPN addresses the automation of networking layers 2 and 3, it does not
address layers 0 and 1. Automating these layers is equally important because
providing an end-to-end service to their customers often requires a manual and
complex negotiation between CSPs that includes both the business arrangement
and the actual service design and activation. CSPs may also be structured such
that they operate multiple networks independently and require similar
transactions among their own networks and business units in order to provide an
end-to-end service. The MDONS blueprint created by AT&T, Orange, and Fujitsu
solves the above problem. MDONS and CCVPN used together can solve the OTN
automation problem in a comprehensive manner.

|image15|

**Figure 15. ONAP MDONS Architecture**

Intent Based Network (IBN) Use Case
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Intent technology can reduce the complexity of management without getting into
the intricate details of the underlying network infrastructure and contribute
to efficient network management. This use case performs a valuable business
function that can further reduce the operating expenses (OPEX) of network
management by shifting the paradigm from complex procedural operations to
declarative intent-driven operations.

|image16|

**Figure 16. ONAP Intent-Based Networking Use Case**

3GPP 28.812, Intent driven Management Service (Intent driven MnS), defines
some key concepts that are used by this initiative. The Intent Based Networking
(IBN) use case includes the development of an intent decision making. This use
case has initially been shown for a smart warehouse, where the intent is to
increase the output volume of automated guided vehicles (AVG) and the network
simply scales in response. The intent UI is implemented in UUI and the
components of the intent framework interact with many components of ONAP
including SO, A&AI, Policy, DCAE and CDS.

vFW/vDNS Blueprint
^^^^^^^^^^^^^^^^^^
The virtual firewall, virtual DNS blueprint is a basic demo to verify that ONAP
has been correctly installed and to get a basic introduction to ONAP. The
blueprint consists of 5 VNFs: vFW, vPacketGenerator, vDataSink, vDNS and
vLoadBalancer. The blueprint exercises most aspects of ONAP, showing VNF
onboarding, network service creation, service deployment and closed-loop
automation. The key components involved are SDC, CLAMP, SO, APP-C, DCAE and
Policy. In the recent releases, the vFW blueprint has been demonstrated by
using a mix of a CNF and VNF and entirely using CNFs.

Verified end to end tests
-------------------------
Use cases
^^^^^^^^^
Various use cases have been tested for the Release. Use case examples are
listed below. See detailed information on use cases, functional requirements,
and automated use cases can be found here:
:doc:`Verified Use Cases<onap-integration:docs_usecases_release>`.

- E2E Network Slicing
- 5G OOF (ONAP Optimization Framework) SON (Self-Organized Network)
- CCVPN-Transport Slicing

Functional requirements
^^^^^^^^^^^^^^^^^^^^^^^
Various functional requirements have been tested for the Release. Detailed
information can be found in the
:doc:`Verified Use Cases<onap-integration:docs_usecases_release>`.

- xNF Integration

  - ONAP CNF orchestration - Enhancements
  - ONAP ASD-based CNF orchestration
  - PNF PreOnboarding
  - PNF Plug & Play

- Lifecycle Management

  - Policy Based Filtering
  - Bulk PM / PM Data Control Extension
  - Support xNF Software Upgrade in association to schema updates
  - Configuration & Persistency Service

- Security

  - CMPv2 Enhancements

- Standard alignment

  - ETSI-Alignment for Guilin
  - ONAP/3GPP & O-RAN Alignment-Standards Defined Notifications over VES
  - Extend ORAN A1 Adapter and add A1 Policy Management

- NFV testing Automation

  - Support for Test Result Auto Analysis & Certification
  - Support for Test Task Auto Execution
  - Support for Test Environment Auto Deploy
  - Support for Test Topology Auto Design

Conclusion
----------
The ONAP provides a comprehensive functions for real-time, policy-
driven orchestration and automation of physical and virtual network functions
that will enable software, network, IT and cloud providers and developers to
rapidly automate new services and support complete lifecycle management.

By unifying member resources, ONAP will accelerate the development of a vibrant
ecosystem around a globally shared architecture and implementation for network
automation —with an open standards focus— faster than any one product could on
its own.

Resources
---------
See the Resources page on `ONAP.org <https://www.onap.org/resources>`_

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