Agent

Iotellect Agent device driver is a Device Driver that allows Iotellect Server to interact with Agent. Technically, Agent is a BASIC application that creates and maintains a Context Tree with a node for each physical Device (piece of hardware) connected to it. Actually, a Device may also be implemented by custom code that is a part of Agent. The variables of each Device context correspond to the Device's settings. Each such context also has functions which let you perform some operations with the Device, and events which are used to monitor the Device's state and changes in its operating conditions. Iotellect Server uses the Iotellect Communications Protocol to communicate with Agent.

This driver differs from Local Agent device driver. The latter establishes outgoing connection in "agent mode" instead of servicing incoming agent connections.

• Port number to listen for Agents. Incoming connections from Agents will be accepted on this port.

• Port number to listen for secure Agent connections. Incoming secure connections from Agents will be accepted on this port.  

• Command Timeout. Timeout for commands sent using Iotellect communication protocol.

• Broadcast Command Timeout. Timeout for commands sent via broadcast during Agents discovery.

• Automatically register device accounts for new Agents. Allows Agents to tell their passwords to Iotellect Server, and forces the server to auto-register Agent accounts if new Agents try to connect.

• Maximum Event Queue Length. Maximum number of a single Agent's events to keep if event processing is delayed due to some reason. If event queue overflows, the remote agent won't be able to send more events.

• Certificate Trust Policy. Defines how to verify certificates provided via an SSL/TLS connection.

• Certificate. Alias of an SSL/TLS certificate to use for authentication. The certificate with that alias must exist in the Client Certificate storage of the Iotellect server.

None defined.

• Authentication. Specify LDAP authentication as the third-party service to authenticate the agent, or authenticate by assigning agent a password.

• Login. The LDAP username of the agent when LDAP authentication is activated.

• Password. Agent's password when no third-party authentication is selected.

• Command Timeout. Timeout for commands sent using the Iotellect communication protocol.

Assets presence is defined by a concrete Agent implementation.

Agent Device Driver exposes remote Agent's variables as local Device settings.

Agent Device Driver exposes remote Agent's functions as local Device operations.

Agent Device Driver exposes remote Agent's events as local Device events.

This driver makes the device Online if:

• An Agent is currently connected to the server and passed login sequence

• Basic Agent operations has completed successfully

Device status dialog for Agent device driver shows an additional Connection Statistics table reporting:

• Connection Duration

• Command Count, i.e. number of commands sent to the Agent

• Average Response Time for all commands

• Incoming Traffic (uncompressed)

• Outgoing Traffic (uncompressed)

• Unreplied Command Count

Agents must be authenticated in order to securely communicate with Iotellect Server. Authentication can be performed by specifying a login to an external authentication service, or specifying a password for the agent for local authentication.

The local authentication method uses the password assigned to the agent and the agent account name on the remote server for authentication. The following parameters are used for local authentication:

• Authentication: A drop-down list indicating external authentication options. For local authentication, set this to Local Authentication.

• Password: Assigns a password to authorize the agent with Iotellect Server.

The external authentication method uses LDAP as a third-party to authenticate the agent, allowing for centralized user authentication and management. The LDAP plugin must be installed and configured in order to use external authentication. The following parameters of the agent are used for external authentication:

• Authentication: The external authentication method LDAP must be selected, hiding the Password property and revealing the Login property.

• Login: The LDAP login to be associated with the agent.

With these settings, when the local agent tries to connect to the central server, the server will use the provided Login and a password provided by a connecting agent to authenticate the agent through the LDAP service.

Agent driver performs synchronization of Iotellect Server and Devices provided by Agent according to the following algorithm:

• Reads the list of available contexts and their parent-child relationship from the Agent.

• Creates a server context for every context found in Agent. This context allows Iotellect users to interact with Agent directly or through a variable cache.

• Synchronizing Agent's internal real-time clock with the time on the server. Time is converted to the time zone specified for the Device.

• Reads definitions of variables, functions and events from every context available in Agent. It doesn't read the values contained within these Data Tables yet -- just their format. More about variable definitions here.

• Finds common tables that may be used as a "master values" for variables found in Agent (such as Device settings).

• Creates a property cache (if this is the first time this Device is connecting) or updates it according to variable definitions read on the previous step. Only variables that belong to the group named default are synchronized with the server and available for editing by users. The property cache is created only in server contexts corresponding to Device contexts in Agent. Variables corresponding to internal Agent settings are modified by the server directly, without a cache.

• Sets up a Configure Device action in every context corresponding to a Device context in Agent.

• Creates an appropriate action for every Device context function within the default group. Such an action allows users to call the Agent function, specify its parameters and view its output.

• Sets up a Monitor Related Events action in every context corresponding to a Device context in Agent to show all events arriving from Agent which belong to the default group.

• Synchronizes variable values between the server cache and Agent for every context corresponding to a Device context in Agent.

The exact structure of communications between Agent and Iotellect Server during synchronization is described under Communications Between Agent and Iotellect Server.

Devices Context provided by Agent can have several additional actions. Most of them are defined by a custom Agent BASIC application. For example, if Agent works with some sensors of terminals that are connected to its serial ports, there may be a Detect Devices action causing Agent to rescan its serial ports, find out which devices are currently connected and update list of provided Device Contexts.

There are two additional actions of Devices Context that are always provided by Agent:

This Configure action is used to configure Agent itself, i.e. set parameters of defining how Agent communicates with hardware devices connected to it, how it converts the native protocol of these devices to Iotellect Communications Protocol and what variables, functions and events are provided by Agent in Device contexts corresponding to these devices.

This action reboots programmable module that runs the Agent BASIC application. Technically, this is a Call Function action that calls reboot function from Agent's root context.

Agent Discovery is the process of locating all hardware Agents in the local network segment and automatically creating Discovered Agent Accounts for them.

A local network segment means there are only network hubs (no routers, bridges, firewalls, etc.) between the PC and all other devices on that segment.

Hardware Agents which are located behind a router (i.e, you have the computer running  Iotellect Server, and to actually get to the Agent its packets need to go via a router) cannot be auto-discovered by Iotellect Server because the broadcast UDP datagrams used to find them on the network are not forwarded by the router. However, it is still sometimes possible to connect such Agents to the Iotellect Server, if they can be accessed by their IP addresses (in other words, if there is a network path to them).

Each discovered Agent is uniquely identified by its MAC-address. Discovery will detect all local Agents even if some of them have the same IP-address or an IP-address which is invalid or unreachable. A correctly configured IP-address is not required for the Iotellect Server to be able to access Agents in the discovery mode.

During the discovery process, Iotellect Server creates a new Discovered Agent context (account) for every Agent detected. All Discovered Agent contexts that were created during previous executions of discovery are destroyed before any new contexts are created. There's no way to "manually" create a Discovered Agent Account, only using the discovery process.

If automatic discovery of Agents is not enabled and it was not launched manually, the Discovery context will not contain any Agent accounts.

Discovery may be initiated by one of the two actions in Discovery context:

• Agents Discovery

• Agents Discovery and Auto-Connection

Connecting an Agent to Iotellect Server is the process of reconfiguring a hardware Agent to make it connect to the Iotellect Server immediately after startup. There are several ways to do this:

• Connecting a previously discovered Agent using its account.

• Automatically connecting all discovered Agents to Iotellect Server without user interaction.

• Manually configuring a discovered Agent that was not successfully connected by the above functions.

• Manually connecting a Agent that was not detected by the discovery process but may be accessed by Iotellect Server.

This procedure is initiated by the Connect Agent to Iotellect Server action of the Discovered Agent context.

The user must specify several parameters before connection process is started:

• Login Password. Required if a password is defined in the settings of the hardware Agent. This password will be used by Iotellect Server to access the settings of the hardware Agent.

• Owner Name. Name of the Iotellect Server user who will own (or already owns) an Agent Account that will be used to authenticate this hardware Agent during its login to Iotellect Server. The "Owner name" setting of the hardware Agent will be set to this value.

• Device Name. Name of the above Device Account. Device name setting of the hardware Agent will be set to this value.

• Force connection even if Agent is already configured for Iotellect Server or has incompatible firmware. By default, the connection procedure fails with an error message if the Agent is already configured to connect to the Iotellect Server or has an outdated firmware version (one that doesn't fully support automated configuration for Iotellect Server). This option disables checking of the Agent setting values and its version number. The forced connection operation will complete successfully, but  Agent may not be able to actually connect to the Iotellect Server or log in. If the Agent does not login to the Iotellect Server within several seconds after the forced connection procedure has been completed, configure the Agent manually (depending on the device type, this can be done using keypad/LCD or web interface).

If discovery was started using Agents Discovery and Auto-Connection action, Iotellect Server automatically executes the Connect discovered Agent to the Iotellect Server procedure for every Agent detected during the discovery process. It is useful for quickly connecting multiple Agents that are plugged into the local network segment.

Automatic connection fails if:

• The Agent requires a password to access its settings, or

• The Agent is already configured for connection with the Iotellect Server on startup, or

• The Agent's firmware does not support auto-connection.

Was this page helpful?

Tell us more

Send

Thank you!