The OPC UA server may respond with a GOOD service result to subscription service requests when the subscription has already timed out.

The OPC UA server may respond with a GOOD service result to subscription service requests when the subscription has already timed out.

Summary

When an OPC UA client disconnects from the zenon OPC UA server and does not send service requests for a subscription for a specified time, the subscription in the zenon OPC UA server times out and becomes invalid. If an OPC UA client reconnects and performs a service request on the subscription, the OPC UA server under circumstances may respond with a GOOD service result, falsely indicating to the client that the subscription is still alive.

Description

When an OPC UA client disconnects from the zenon OPC UA server and does not send service requests for a subscription for a specified time, the subscription in the zenon OPC UA server times out and becomes invalid. If an OPC UA client reconnects and performs a service request on the subscription, the OPC UA server under circumstances may respond with a GOOD service result, falsely indicating to the client that the subscription is still alive.

Solution

An issue has been addressed in the zenon OPC UA server where subscription service requests did not always validate the subscription status. Now the subscription status is considered correctly and the OPC UA server returns an error BadSubscriptionInvalid when the subscription has timed out.


Information




Issue Number: 34295
Fixed on Date: 1.6.2015
Versions: 7.11 0 BUILD 20530