Team

NameOrganizationEmail
Patrick LiuHuawei Technologiespartick.Liu@huawei.com
Thomas VachuskaOnLabtom@onlab.us
Gaurav AgrawalHuawei Technologies

gaurav.agrawal@huawei.com

Bharat SaraswalHuawei Technologiesbharat.saraswal@huawei.com
Sonu GuptaHuawei Technologiessonu.gupta@huawei.com
Janani BHuawei Technologiesjanani.b@huawei.com
Vidyashree RamaHuawei Technologiesvidyashree.rama@huawei.com 
Vinod Kumar SHuawei Technologies vinods.kumar @huawei.com
Adarsh MHuawei Technologiesadarsh.m@huawei.com
KalyankumarAsangiHuawei Technologieskalyana@huawei.com
A U SuryaHuawei Technologiesa.u.surya@huawei.com

 

Overview

ONOS dynamic configuration subsystem is developed with a purpose to allow service providers to access the configuration capabilities of various devices as prescribed by their YANG models and similarly to allow the service providers to define YANG models for their own network services. The system should be composed in a modular fashion and using isolated and reusable components to assure proper separation of concerns among them. YANG runtime is one of its component.YANG runtime serves as a registry of various YANG models in the system and its primary purpose is serialization and deserialization from various external formats (XML, JSON, Kryo) and their internal Java representations (based on DataNode base-class). Users (and applications) should be able to register new models and new serializers at runtime.

The YANG runtime must remain independent from any transport protocols (e.g. RESTCONF,NETCONF) and any storage or messaging mechanisms. Implementations of outward-facing protocols should depend on the YANG runtime to serialize and deserialize their payloads, and the Dynamic Config subsystem will depend on the YANG runtime to serialize these objects for distribution and persistence. However, none of these outward facing or storage concerns should permeate into the YANG runtime. It should be deployable in a standalone JVM, OSGi, or ONOS environment. Schema agnostic application will act upon the ModelObject based on YANG compiler's generated code. YANG runtime enables the model conversion between the DataNode and POJO.

Moreover YANG runtime is also a schema context provider which can be used by other applications/dynamic config subsystem components to obtain a specific schema context.

YANG Runtime Architecture

The runtime serves as a registry of various YANG models in the system and its primary purpose is serialization and deserialization from various external formats (XML, JSON, Kryo) and their internal Java representations (based on DataNode base-class).

Users (and applications) should be able to register new models and new serializers at runtime.

The YANG runtime is independent from any transport protocols (e.g. RESTCONF, NETCONF) and any storage or messaging mechanisms.

Implementations of outward-facing protocols depend on the YANG runtime to serialize and deserialize their payloads and the dynamic Config subsystem will depend on the YANG runtime to serialize these objects for distribution and persistence.

 

          

Serializer Registry 

This service is used for registering and unregistering the available data format serializers. YANG App activation registers the default XML/JSON serializers. User can override the existing registration or can register new data formats. In case of multiple registrations of same data format, last one will take into effect.

The YangSerializerRegistry interface provides 2 API's:

void registerSerializer(YANGSerializer serializer)
void unregisterSerializer(YANGSerializer serializer)

Model Registry 

This API is used by schema aware application to register YANG model. Example:L3VPN application and also live compiler.

Example: When L3VPN application wants to register L3VPN service model it has to extend the AbstractYangModelRegistrator which allows the application to attach endpoints to the respective service model. 

public class L3VpnModelRegistrator extends AbstractYangModelRegistrator {
    /**
     * Creates L3VPN model registrator.
     */
    public L3VpnModelRegistrator() {
        super(IetfL3VpnSvc.class, getAppInfo());
    }
    private static Map<YangModuleId, AppModuleInfo> getAppInfo() {
        Map<YangModuleId, AppModuleInfo> appInfo = new HashMap<>();
        appInfo.put(new DefaultYangModuleId("ietf-inet-types", "2013-00-15"),
                    new DefaultAppModuleInfo(IetfInetTypes.class, null));
        appInfo.put(new DefaultYangModuleId("ietf-l3vpn-svc", "2016-00-30"),
                    new DefaultAppModuleInfo(IetfL3VpnSvc.class, null));
        appInfo.put(new DefaultYangModuleId("ietf-yang-types", "2013-00-15"),
                    new DefaultAppModuleInfo(IetfYangTypes.class, null));
        appInfo.put(new DefaultYangModuleId("l3vpn-svc-ext", "2016-00-30"),
                    new DefaultAppModuleInfo(L3VpnSvcExt.class, null));
        return ImmutableMap.copyOf(appInfo);
    }
}

The YangModelRegistry interface provides the following methods: 

void registerModel(ModelRegistrationParam param)
 void unregisterModel(ModelRegistrationParam param)

Each model or application will have a unique identifier known as model-Id, which can be used to get YANG model for an application. 

Runtime Service 

It is a service for encoding and decoding between internal and external model representation.

The decode method decodes the external representation of a configuration model from the specified composite stream into an in-memory representation. Resource identifier stream will get decoded to data node.

Protocols like NETCONF may opt only to have resource data without resource identifier, which implies the data node construction from logical root resource("/").

Also protocols like NETCONF will have decorations around the input stream which will be reported back to protocol in output. Produced annotations will be in order of pre-order traversal.

CompositeData decode(CompositeStream external, RuntimeContext context)

The encode method encodes the internal in-memory representation of a configuration model to an external representation consumable from the resulting input stream.Resource identifier in composite data will get encoded to resource data stream.

Logical root node "/" will be removed during encoding and will not be part of either resource identifier or data node.

Protocols like NETCONF may opt only to have data node with resource identifier as null in order to only get complete output in form of body without URI.

Also protocols like NETCONF would like to provide additional decorations for the node. The decoration should be in pre-order traversal order.

CompositeStream encode(CompositeData internal, RuntimeContext context)

ModelConverter Service 

Model converter provides a mechanism for converting between DataNode and Model Object instances. It is capable of constructing model POJO objects from the DataNode,including any augmentations which may be present in the DataNode structure and creating immutable tree structure from a given POJO. This API mainly gives the following methods:

ModelObject createModel(DataNode)
DataNode createDataNode(ModelObject)

SchemaContext Provider 

It returns an entity that provides schema context corresponding to a given resource identifier.

SchemaContext getSchemaContext(ResourceId id)

Helper Utils

Use Case Scenarios Of YANG Runtime