Welcome back. In this lesson, I'll talk about a commercial grade controller called OpenDaylight. I'll provide an overview of OpenDaylight, including a consortium of industry partners who are involved in the effort, as well as an overview of the OpenDaylight controller architecture. Also give a demonstration of the OpenDaylight controller in action. Including showing the life of a packet through a simple Mac learning switch application. As well as the web interface to the OpenDaylight controller. In doing so, I'll talk about essential OpenDaylight functions that you need to implement to write a very basic OpenDaylight control application. More information about OpenDaylight is available on sdnhub.org, which is the source of a lot of the information that I'm providing in this lesson. [UNKNOWN] and [UNKNOWN] deserve a lot of credit for putting together much of this material. The OpenDaylight Consortium has heavy industry involvement and backing. It's focussed on providing an open frame work for building on various SDN and network function virtualization innovations that are being developed across the industry. The OpenDaylight controller is not limited to open flow innovations. It supports many different south bound API's. And perhaps no controller better illustrates the concept that SDN is much, much broader than just OpenFlow. Here's an illustration of the OpenDaylight controller release called Hydrogen. At the very bottom of the architecture, we have OpenFlow enabled switches. Open B switches, or software switches. Maybe additional other virtual and physical devices and other data plan elements. It's important to note that these need be open flow switches. In fact, when you look at the south bound interfaces, that the open daylight controller supports, open flow is just one south bound interface that it aims to support. It also supports many other Southbound interfaces including Netcomf and OVSCP, as well as more conventional network management and configuration protocols. In between the Southbound interface and the controller platform itself, OpenDaylight provides what's called a service abstraction layer. Which abstracts the southbound interfaces from the modules that are provided by the controller platform. This abstraction layer, or cell, is the main difference between OpenDaylight and more open-flow centric controller platforms. The controller platform implements various basic services on top of the cell. And on top of the controller itself one can use the OpenDaylight REST API's to write more complex network applications for orchestration and network services. The OpenDaylight ecosystem has many moving parts. The controller's written in Java. Java was chosen as an enterprise-grade, cross-platform compatible language. OpenDaylight uses Maven as a build system, and we'll see that in action during the demonstration. It also uses OSGI to allow the controller to dynamically load bundles, automatically register dependencies and services. And to exchange information across bundles. We'll look at an example of how OSGI allows dynamic loading of bundles in the demonstration of the Mac learning switch. OpenDaylight provides Java interfaces for event listening, specification and various patterns. In the example that we'll look at, a packet will arrive. At a particular switch will be sent to the appropriate plugin that's managing the switch at the control log. The plugin will parse the packet and generate an event for the service abstraction layer. The service abstraction layer dispatches the packet to modules that are listening for data packet events using the iListenDataPacket interface. These modules, such as an ARP Handler or a MAC Learning Switch, handle the packet and send the packet out through the iDataPacketService. SAL then dispatches the packet to the modules that are listening for data packets. And the controller will also send OpenFlow messages to the appropriate switches such as flow modification directives. Let's now have a look at the open daylight controller running a simple Mac learning switch. First going to start a simple three node mini-net topology. With one switch. We can see that with no controller, as before, there's no connectivity between the host and the network. I'm not going to install the tutorial code, using the Maven MVN tool. In the end is the Maven command that compiles the code based on the palm.xml file in that directory. Maven resolves dependencies between pathogens. And the code that we're using here depends on the open daylight controller package. So, Maven will download the pre-compiled .jar files from opendaylight.org, resolve dependencies, and so on. This takes a while, but we can eventually run the command SS Tutorial to see that our tutorial bundle running the Mac learning switch is in fact running. Initially we started the controller running a hub. Now I'll illustrate the power of OSGI's ability to dynamically load bundles by changing the hub to a switch on the fly. So I've changed the function of the control program from a hub to a switch. And now I'll use Maven to dynamically reinstall the bundle. You can see that once the switch bundle is reinstalled, the the roundtrip times drop from milliseconds to less that one millisecond. >> Open Daylight also provides a cool web interface to allow the operator or programmer to see the network topology and the flows installed at each switch. Like any controller. The OpenDaylight controller has three essential types of code hotspots. One for handling packet in messages or packet arrivals. Another for parsing themselves as they arrive at the controller, and a third for sending control messages to switches. You can see in these code snippets that there are several similarities between Beacon and OpenDaylight. While the code itself here look similar, you should by now be noticing that the above three types of functions are common to all controller platforms. Here's the code and controller that illustrates the main logic behind the Mac learning switch. The logic is contained in the received data packet call back. If the function of our controller is a hub, we simply flood the pack. But as you recall, we changed the function from a hub to a switch so we'll execute this branch. The first thing that we do is decode the pack. The control program then learns the source MAC address of the incoming pack. If the outgoing port of the packet cannot be determined, the control program simply floods the packet on all output ports. Otherwise we install the corresponding rule in the flow table of the switch, set the outgoing port, and then transmit the data packet. Let's have a quick look at the program flow function, which sets the match action entrance in the switch. Here you can see, the program flow function. Where we set the match type, and the corresponding actions. And then modify the flow, on the corresponding switch, using the AddFlow function. Open Daylight provides many useful interfaces and bundles that you may wish to use, ranging from things that track hosts across the network, to keeping track of the network's topology, to keeping track of various users and statistics. Here are examples of some more user interfaces and bundles. Including this that support the topology methods, modifying flows in switches, and support for the web UI itself. In summary, OpenDaylight is an industry backed effort to develop a broader set of SDN solutions. Perhaps more than other controller OpenDaylight illustrates that SDN is just OpenFlow but it is possible to integrate a broad set of southbound API's and provide support for various types of cloud-based applications as well. It's important to note, of course, that writing a basic control program in OpenDaylight is very similar to that of other controllers because there's a very common set of basic functions that any controller provides. And like packet arrivals, parsing of packets, and exchanging messages with the switches themselves, the learning curve for OpenDaylight is significant. But SDN Hub has a great starter kit, including a virtual machine that I've used to show you this demonstration. And that we've provided on the course website. I strongly encourage you to check it out and play with it yourself.
