If under specific circumstances an OPCUA server is not capable of sending a publish response with a keep alive message in time the OPCUA client may assume that the OPCUA server is no longer available. A grace period is applied of 1000ms. Under specific circumstances this grace period may be too short, e.g. where the TCP retransmit timeout is more than 300ms.
The OPCUA client driver sets the timeoutHint in the publish request header to 3 x publish interval x maxkeepalive count. As the OPCUA client only creates a single subscription and makes sure that at most 2 publish requests are outstanding in the OPCUA server, the publish request expires according to the timeoutHint only after the OPCUA client driver has already established that the OPCUA server is no longer available.
The timeoutHint in the service request header for the publish request may be used by an OPCUA server to determine that the request is no longer valid and an OPCUA server may delete the publish request to free up resources, and cancel the service request with the OPCUA client.
If under specific circumstances an OPCUA server is not capable of sending a publish response with a keep alive message in time the OPCUA client may assume that the OPCUA server is no longer available. A grace period is applied of 1000ms. Under specific circumstances this grace period may be too short, e.g. where the TCP retransmit timeout is more than 300ms.
The OPCUA client driver sets the timeoutHint in the publish request header to 3 x publish interval x maxkeepalive count. As the OPCUA client only creates a single subscription and makes sure that at most 2 publish requests are outstanding in the OPCUA server, the publish request expires according to the timeoutHint only after the OPCUA client driver has already established that the OPCUA server is no longer available.
The timeoutHint in the service request header for the publish request may be used by an OPCUA server to determine that the request is no longer valid and an OPCUA server may delete the publish request to free up resources, and cancel the service request with the OPCUA client.
The grace period which the OPCUA client driver waits after a publish response was due from the server has been increased to 5000ms.
The timeoutHint in the header of the publishrequest now corresponds to the session lifetime. (revised publish interval x revised lifetimecount)