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OpenDaylight concepts and tools

In this section we discuss some of the concepts and tools you encounter with basic use of OpenDaylight. The guide walks you through the installation process in a subsequent section, but for now familiarize yourself with the information below.

  • To date, OpenDaylight developers have formed more than 50 projects to address ways to extend network functionality. The projects are a formal structure for developers from the community to meet, document release plans, code, and release the functionality they create in an OpenDaylight release.

    The typical OpenDaylight user will not join a project team, but you should know what projects are as we refer to their activities and the functionality they create. The Karaf features to install that functionality often share the project team’s name.

  • Apache Karaf provides a lightweight runtime to install the Karaf features you want to implement and is included in the OpenDaylight platform software. By default, OpenDaylight has no pre-installed features.

    Features and feature repositories can be managed in the Karaf configuration file etc/org.apache.karaf.features.cfg using the featuresRepositories and featuresBoot variables.

  • Model-Driven Service Abstraction Layer (MD-SAL) is the OpenDaylight framework that allows developers to create new Karaf features in the form of services and protocol drivers and connects them to one another. You can think of the MD-SAL as having the following two components:

    1. A shared datastore that maintains the following tree-based structures:
      1. The Config Datastore, which maintains a representation of the desired network state.
      2. The Operational Datastore, which is a representation of the actual network state based on data from the managed network elements.
    2. A message bus that provides a way for the various services and protocol drivers to notify and communicate with one another.
  • If you’re interacting with OpenDaylight through the REST APIs while using the OpenDaylight interfaces, the microservices architecture allows you to select available services, protocols, and REST APIs.