Control networks consist of intelligent devices like switches, thermostats, pumps, motors, valves, controllers, and a variety of other sensors and actuators that communicate with each other to provide distributed monitoring and control. A control network may be a small, simple network consisting of a few devices; may be a large network in a building, factory, or ship consisting of tens of thousands of devices; or may even be a very large regional network consisting of millions of devices. In every case, the devices in the network must be configured to become part of a common network, and to exchange data amongst themselves. The process of configuring devices in a control network to establish communication among the devices is called network installation.
Networks can be categorized by the method used to perform network installation. The two categories of networks are managed networks and self-installed networks. A managed network is a network where a shared network management server is used to perform network installation. A user typically uses a tool to interact with the server and define how the devices in the network should be configured and how they should communicate. Such a tool is called a network management tool. For example, Echelon’s IzoT Commissioning Tool is a network management tool that uses a network management server called the IzoT Network Services Server to install devices in a network. Although a network management tool and a server are used to initially establish network communication, they need not be present all the time for the network to function. The network management tool and server are only required whenever changes are made to the network’s configuration.
In a managed network, the network management tool and server allocate various network resources, such as device and datapoint addresses. The network management server is also aware of the network topology, and can configure devices for optimum performance within the constraints of the topology.
In a self-installed network, there is no central tool or server that manages all of the network configuration in a self-installed network. Instead, each device contains code that replaces parts of the network management server’s functionality, resulting in a network that no longer requires a special tool or server to establish network communication or to change the configuration of the network.
Devices in a self-installed network cannot rely on a network management server to coordinate their configuration. Since each device is responsible for its own configuration, a common standard is required to ensure that devices configure themselves in a compatible way. The standard protocol for performing self-installation in IzoT networks is called the IzoT Interoperable Self-Installation (ISI) Protocol. The ISI protocol can be used for networks of up to 300 devices. Larger or more complex networks must either be installed as managed networks, or must be partitioned into multiple smaller subsystems, where each subnetwork has no more than 300 devices and meets the ISI topology and connection constraints. Devices that conform to the IzoT ISI protocol are called ISI devices. ISI is fully integrated with the IzoT Device Stack EX and is enabled by default.
Networks can start out as self-installed networks using ISI and, as size or complexity grows beyond the ISI limits, can be upgraded into a managed network. A self-installed network may also be transitioned to a managed network to take advantage of the additional flexibility and capability provided by a network management tool and server.
ISI provides two key services to your IzoT application and the peer-to-peer control network of IzoT devices.
- ISI enables devices to allocate a unique logical network address to themselves, and to maintain its uniqueness. Logical addresses support network segmentation and routing, are generally more efficient, and support transparent replacement of a physical device.
- ISI provides services which help you and your applications establish connections between datapoints. These connections are key to a peer-to-peer control network.