For TCP Listener device troubleshooting, the following sections list common tasks and problems.
Common TCP Listener tasks and problems
Verify the proper license keys are installed
The features and functions available in a node are controlled by the licenses that are installed in the node.
To verify that the appropriate device license is installed:
- From the Workbench left pane, expand the node whose license you want to check, and then select the Administration icon.
- From the Administration window, select the Licenses tab.
- Select the appropriate license. Details of the license appear on the tab.
- View the Features column to identify the device driver.
If you do not see the correct license, or if the license is expired, you must request a license from your license key provider.
For information on how to install a license, refer to System Administration > Licenses.
Active device license count exceeded
The number of active partner TCP application connections has exceed the total active device license count. The connection from the partner TCP application has been rejected by the TCP Listener device.
A system generated Alert will be displayed when the
number of active device licenses in use exceeds a threshold
percentage of the total active device licenses for the
node. The Alert is cleared when the usage drops below the
threshold percentage. For example:
An Exceptions Log message is inserted for the first
connection rejection. For example:
"Device connection rejected due to insufficient device
licenses"
For more information, see Licenses.
Unable to define a TCP Listener device
The TCP Listener device support is not part of this node's installation. The TCP Listener device support is installed as a package separate from the base product installation.
You may be working with different levels of nodes, each with different levels of support for devices. Ensure that this node is the one with support for the TCP Listener device.
For information on how to add the TCP package, refer to System Administration > Packages.
Unable to Validate or Start a TCP Listener device
The default TCP port used by a TCP Listener device is 6000, which can be configured to use another port. If you have another TCP Listener device defined that is using the port, or if another service is using the port, the TCP Listener device will not be able to start. In this situation you will either have to free this port or configure the TCP Listener device to use a different port. If a different port is selected, ensure that the partner TCP applications that are connecting to TCP Listener device are aware of the new port designation.
The partner TCP application's connection to a TCP Listener device won't go away.
The TCP Listener device allows you to define a maximum number of partner TCP applications that can be connected at one time. The TCP driver keeps a running count of how many partner TCP applications are actively connected while it is running. TCP partner applications that attempt to connect to a TCP Listener device once the maximum connection count has been reached will be rejected by the TCP driver. The active connection value is decremented when a partner TCP application closes its socket connection to the TCP Listener device, which will allow a new partner TCP application to connect, in the scenario where the maximum connection count has been reached.
The TCP driver, running on the Linux operating system, may not be notified of socket error conditions that originate from the partner TCP application. If the TCP driver is not notified of these error conditions, then the TCP Listener device will not decrement the active connection count when the partner TCP application error occurs. An example of this would be a partner TCP application whose Ethernet cable becomes disconnected after it had previously connected to the TCP driver on a Linux node. Linux does not raise this disconnected socket error condition to the TCP driver, so the TCP driver has no way of knowing this partner TCP application is no longer connected. If the TCP Listener device has reached its maximum number of connections limit, no further connections can be accepted until the Linux operating system notifies the TCP driver of the invalid partner TCP application connection. Once the TCP driver has been notified, it will close the connection and decrement the active connections counter, which will make available an additional connection.