Number of Sessions per Client-Server Connection

[dominik0071]

I use Milo Client 0.6.15 to connect to the OPC UA server on the device, where the open62541 library is used.

Milo Client is used for the repetitive read, call methods requests - just gathering data based on scheduled operations.

When the device is disconnected from the network and then connected again, the server is overwhelmed with several sessions created by one instance of Milo Client. Other applications, e.g., UA Expert, can't successfully connect to the OPC UA server. Usually, there is an error: Bad Session ID invalid, but not every time.

Is there an option to set up a maximum number of sessions created by one client in Milo?

What is the recommended settings (timeout, keep-alive-interval etc.) for the long-running connection on the expected bad network?

Do asynchronous requests create sessions per each?

[kevinherron]

Each OpcUaClient creates one Session at a time. It deletes the Session when you call disconnect().

What may be happening is that you lose your connection to this server (often because it stops responding) and then the Milo Client reconnects and creates a new Session.

If you turn on DEBUG logging for org.eclipse.milo.opcua.sdk.client.SessionFsm and/or get a Wireshark capture I can get a better sense for what is happening.