Purpose of this wiki

The purpose of this wiki is to have the architecture text that needs to be modified. The source of this is the London Architecture in read-the-docs.

The text should be release independent, then copied back to read-the-docs.

Architecture text

.. This work is licensed under a Creative Commons Attribution
.. 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0
.. 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

.. _ONAP-architecture:

Architecture
============
ONAP is a comprehensive platform 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.

The ONAP project addresses the rising need for a common automation platform 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). These challenges are still very real now as 
ONAP creates its fourth release.

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
multiple VNF environments by integrating with multiple VIMs, VNFMs, SDN 
Controllers, as well as legacy equipment (PNF). 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 platform 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 platform,
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 platform and related components. This is in 
stark contrast to traditional OSS/Management software platform architectures, 
which hardcoded services and technologies, and required lengthy software 
development and integration cycles to incorporate changes.

The ONAP Platform 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 APIs for new services and
  technologies without the need for new platform 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 interaction 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

|image1|



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

Architecture overview navigation portal: https://safratech.net/onapdocs21/action_page.php?release=istanbul&doc_type=arch-overview 

Component Function Summary
--------------------------













Simplified Functional View of the Architecture
----------------------------------------------

The Figure 2 below, provides a simplified functional view of the architecture,
which highlights the role of a few key components:

#. ONAP Design time environment for onboarding services and resources 
   into ONAP and designing required services.
#. External API provides northbound interoperability for the ONAP Platform.
   Multi-VIM/Cloud provides cloud interoperability for the ONAP workloads.
#. 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.

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, TM Forum SID, ONF Core, OASIS TOSCA, IETF, and MEF.

|image2|



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

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

The ONAP deployment methodology needs to 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. And the platform needs to be highly reliable, scalable, 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
optimization such as shared databases and the use of standardized lightweight
container operating systems reduce the overall ONAP footprint.

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 platform 
deployment. In addition, OOM helps enhance ONAP platform maturity by providing 
scalability and resiliency enhancements to the components it manages.

OOM is the lifecycle manager of the ONAP platform 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. 

Starting with the Istanbul-R9, as a PoC, OOM provides Service Mesh-based
mTLS (mutual TLS) between ONAP components to secure component communications,
by leveraging Istio. The goal is to substitute (unmaintained) AAF 
functionalities. 

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

|image3|

  
**Figure 3. Security Framework component architecture**

Microservices Bus (MSB)
^^^^^^^^^^^^^^^^^^^^^^^
Microservices Bus (MSB) provides fundamental microservices supports including
service registration/ discovery, external API gateway, internal API gateway,
client software development kit (SDK), and Swagger SDK. When integrating with
OOM, MSB has a Kube2MSB registrar which can grasp services information from k8s
metafile and automatically register the services for ONAP components.

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

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.

Portal
------

.. warning:: The ONAP :strong: 'portal' project is :strong:'unmaintained'.

Note: A new Portal-NG replaces the existing Portal.

ONAP delivers a single, consistent user experience to both design time and
runtime environments, based on the user's role. Role changes are configured
within a single ONAP instance.

This user experience is managed by the ONAP Portal, which provides access to
design, analytics and operational control/administration functions via a
shared, role-based menu or dashboard. The portal architecture provides
web-based capabilities such as application onboarding and management,
centralized access management through the Authentication and Authorization
Framework (AAF), and dashboards, as well as hosted application widgets.

The portal provides an SDK to enable multiple development teams to adhere to
consistent UI development requirements by taking advantage of built-in
capabilities (Services/ API/ UI controls), tools and technologies. ONAP also
provides a Command Line Interface (CLI) for operators who require it (e.g., to
integrate with their scripting environment). ONAP SDKs enable
operations/security, third parties (e.g., vendors and consultants), and other
experts to continually define/redefine new collection, analytics, and policies
(including recipes for corrective/remedial action) using the ONAP Design
Framework Portal.

Design Time Framework
=====================
The design time framework is a comprehensive development environment with
tools, techniques, and repositories for defining/ describing resources,
services, and products.

The design time framework facilitates 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 platform 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 also 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.

To support and encourage a healthy VNF ecosystem, ONAP provides a set of VNF
packaging and validation tools in the VNF Supplier API and Software Development
Kit (VNF SDK) and VNF Validation Program (VVP) components. 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. In addition, the testing capability of VNFSDK is being utilized at the LFN
Compliance Verification Program to work towards ensuring a highly consistent 
approach to VNF verification. 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
^^^^^^^
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
^^^
VVP provides validation for the VNF Heat package.

Runtime Framework
-----------------
The runtime execution framework executes 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 
ONAP 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.
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, MSMF
(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 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
- 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 ASD-based CNF models and packages
- 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 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 #1 and #4.

|image 4|

**Figure 4: ONAP Networking Slicing Support Options**

Virtual Infrastructure Deployment (VID)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. warning:: The ONAP :strong:'vid' project is :strong:'unmaintained'.
.. warning:: The ONAP :strong:'vid' component is no longer part of the ONAP
   deployment from the London release.

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
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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, platform capabilities, and other
service specific 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 NFV-O 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:'unmaintained'.

ONAP has two application level configuration and lifecycle management modules 
called SDN-C and App-C. Both provide similar services (application level 
configuration using NetConf, Chef, Ansible, RestConf, etc.) and lifecycle 
management functions (e.g., Stop, resume, health check, etc.).  
They share common code from CCSDK repo.  However, there are some differences 
between these two modules (SDN-C uses CDS only for onboarding and 
configuration / LCM flow design, whereas App-C uses CDT for the LCM functions
for self service to provide artifacts storing in App-C Database).  
SDN-C has been used mainly for Layer1-3 network elements and App-C is
being used for Layer4-7 network functions. This is a very loose
distinction and we expect that over time we will get better alignment and
have common repository for controller code supporting application level
configuration and lifecycle management of all network elements (physical or
virtual, layer 1-7). Because of these overlaps, we have documented SDN-C and
App-C together. ONAP Controller Family (SDN-C / App-C) configures and maintains
the health of L1-7 Network Function (VNF, PNF, CNF) and network services
throughout their lifecycle:

- Configure Network Functions (VNF/CNF/PNF)
- Provides programmable network application management platform:

  - 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. 
  - operational 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,
crate 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.

Policy Framework
^^^^^^^^^^^^^^^^
The Policy framework provides policy based decision making capability and 
supports multiple policy engines and can distribute policies through policy 
design capabilities in SDC, simplifying the design process.

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)

Closed Control Loop Automation Management Platform Function in Policy (Policy - CLAMP)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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 5.

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. 

|image5|

**Figure 5: ONAP Closed Control Loop Automation**

Virtual Function Controller (VFC)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
DMaaP provides data movement service such as message routing and data routing.

Use Case UI (UUI)
^^^^^^^^^^^^^^^^^
UUI provides the capability to instantiate the blueprint User Cases and
visualize the state.

CLI
^^^
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 provide access management and security enforcement, data backup,
configuration persistence, restoration and recovery. They support standardized
VFN interfaces and guidelines.

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

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

.. warning:: The ONAP :strong:'Logging Framework' project is a reference 
implementation 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. Its details in
:ref:'CPS - Configuration Persistence Service<onap-cps:architecture>'.

ONAP Modeling
-------------
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/SO-NFVO, SOL003 from
  either the SO (thru SOL003 Adapter) or VFC to an external VNFM).
- Application Service Descriptor (ASD) v1.0 specification for the CNF is approved, and 
  ASD specification is promoted as the O-RAN standard.

Read this white paper 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 platform 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 three 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 and 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.

|image6|

**Figure 6. 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).

|image 7|

** Figure 7. 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.

|image8|

**Figure 8. 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>'-

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).

|image9|

**Figure 9. 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.

|image10|

**Figure 10. ONAP VoLTE Architecture Open Network Automation Platform**

Read the 'VoLTE Blueprint <https://www.onap.org/wp-content/uploads/sites/20/2018/11/ONAP_CaseSolution_VoLTE_112918FNF.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.

|image11|

**Figure 11. 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 resource 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 and 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.

|image12|

**Figure 12. 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.

|image 13|

**Figure 13. 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 release, 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>'.

- 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 Automatic Platform

  - 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 platform provides a comprehensive platform 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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