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Virtual Tenant Network (VTN)

OpenDaylight Virtual Tenant Network (VTN) Overview

OpenDaylight Virtual Tenant Network (VTN) is an application that provides multi-tenant virtual network on an SDN controller.

Conventionally, huge investment in the network systems and operating expenses are needed because the network is configured as a silo for each department and system. Therefore various network appliances must be installed for each tenant and those boxes cannot be shared with others. It is a heavy work to design, implement and operate the entire complex network.

The uniqueness of VTN is a logical abstraction plane. This enables the complete separation of logical plane from physical plane. Users can design and deploy any desired network without knowing the physical network topology or bandwidth restrictions.

VTN allows the users to define the network with a look and feel of conventional L2/L3 network. Once the network is designed on VTN, it will automatically be mapped into underlying physical network, and then configured on the individual switch leverage SDN control protocol. The definition of logical plane makes it possible not only to hide the complexity of the underlying network but also to better manage network resources. It achieves reducing reconfiguration time of network services and minimizing network configuration errors. OpenDaylight Virtual Tenant Network (VTN) is an application that provides multi-tenant virtual network on an SDN controller. It provides API for creating a common virtual network irrespective of the physical network.

VTN Architecture

VTN Architecture

It is implemented as two major components

VTN Manager

An OpenDaylight Plugin that interacts with other modules to implement the components of the VTN model. It also provides a REST interface to configure VTN components in OpenDaylight. VTN Manager is implemented as one plugin to the OpenDaylight. This provides a REST interface to create/update/delete VTN components. The user command in VTN Coordinator is translated as REST API to VTN Manager by the OpenDaylight Driver component. In addition to the above mentioned role, it also provides an implementation to the OpenStack L2 Network Functions API.

Function Outline

The table identifies the functions and the interface used by VTN Components:

Component Interface Purpose
VTN Manager RESTful API Configure VTN Virtualization model components in OpenDaylight
VTN Manager Neutron API implementation Handle Networks API from OpenStack (Neutron Interface)
VTN Coordinator RESTful API (1) Uses the RESTful interface of VTN Manager and configures VTN Virtualization model components in OpenDaylight. (2) Handles multiple OpenDaylight orchestration. (3) Provides API to read the physical network details. See samples for usage.

Feature Overview

There are three features

  • odl-vtn-manager provides VTN Manager’s JAVA API.
  • odl-vtn-manager-rest provides VTN Manager’s REST API.
  • odl-vtn-manager-neutron provides the integration with Neutron interface.

REST Conf documentation for VTN Manager, please refer to:

For VTN Java API documentation, please refer to:

VTN Coordinator

The VTN Coordinator is an external application that provides a REST interface for an user to use OpenDaylight VTN Virtualization. It interacts with the VTN Manager plugin to implement the user configuration. It is also capable of multiple OpenDaylight orchestration. It realizes VTN provisioning in OpenDaylight instances. In the OpenDaylight architecture VTN Coordinator is part of the network application, orchestration and services layer. VTN Coordinator will use the REST interface exposed by the VTN Manger to realize the virtual network using OpenDaylight. It uses OpenDaylight APIs (REST) to construct the virtual network in OpenDaylight instances. It provides REST APIs for northbound VTN applications and supports virtual networks spanning across multiple OpenDaylight by coordinating across OpenDaylight.

VTN Coordinator Components:

  • Transaction Coordinator
  • Unified Provider Physical Layer (UPPL)
  • Unified Provider Logical LAyer (UPLL)
  • OpenDaylight Controller Diver (ODC Driver)

OpenDaylight Virtual Tenant Network (VTN) API Overview

The VTN API module is a sub component of the VTN Coordinator and provides the northbound REST API interface for VTN applications. It consists of two subcomponents:

  • Web Server
  • VTN service Java API Library


Web Server

The Web Server module handles the REST APIs received from the VTN applications. It translates the REST APIs to the appropriate Java APIs.

The main functions of this module are:

  • Starts via the startup script
  • VTN Application sends HTTP request to Web server in XML or JSON format.
  • Creates a session and acquire a read/write lock.
  • Invokes the VTN Service Java API Library corresponding to the specified URI.
  • Returns the response to the VTN Application.
WebServer Class Details

The list below shows the classes available for Web Server module and their descriptions:

Init Manager
It is a singleton class for executing the acquisition of configuration information from properties file, log initialization, initialization of VTN Service Java API Library. Executed by init() of VtnServiceWebAPIServlet.
Configuration Manager
Maintains the configuration information acquired from properties file.
Utility class
Utility class
Receives HTTP request from VTN Application and calls the method of corresponding VtnServiceWebAPIHandler. herits class HttpServlet, and overrides doGet(), doPut(), doDelete(), doPost().
Creates JsonObject( from HTTP request, and calls method of corresponding VtnServiceWebAPIController.
Creates RestResource() class and calls UPLL API/UPPL API through Java API. the time of calling UPLL API/UPPL API, performs the creation/deletion of session, acquisition/release of configuration mode, acquisition/release of read lock by TC API through Java API.
Data Converter
Converts HTTP request to JsonObject and JsonXML to JSON.
VTN Service Java API Library

It provides the Java API library to communicate with the lower layer modules in the VTN Coordinator. The main functions of this library are:

  • Creates an IPC client session to the lower layer.
  • Converts the request to IPC framework format.
  • Invokes the lower layer API (i.e. UPPL API, UPLL API, TC API).
  • Returns the response from the lower layer to the web server
  • VTN Service Java API Library Class Details

Feature Overview

VTN Coordinator doesn’t have Karaf features.

For VTN Coordinator REST API, please refer to: