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Connecting Client -> Server without network connection

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08 Jun 2017 07:29 #5213 by Captain_Dash
Yes I truly physically disconnect the network cable from the network socket.

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07 Jun 2017 20:12 #5211 by support
Are you truly physically connecting/disconnecting the network cable, or are you doing something related/similar instead, such as disabling the network adapter or disconnecting it in the virtual machine?

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07 Jun 2017 16:15 #5208 by Captain_Dash
I tried DiscoverServers *with* and *withoutParmeters*. The result was the same.

When the network cable was connected, the server could be found with both methods.

When the network cable was disconnected DiscoverServers throws a Exception

OpcLabs.EasyOpc.UA.OperationModel.UAException: An OPC-UA operation failure with error code -2138963968 (0x80820000) occurred, originating from ''. The inner OPC-UA service exception with service result 'BadTcpInternalError' contains details about the problem.


The Inner exception is an UAServiceException

Error establishing a connection.

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07 Jun 2017 15:18 #5207 by support
Can you first clarify the symptoms please?

Are you saying that when you call DiscoverServers *without parameters* (resulting in a search on the local machine), it will discover the local OPC UA server properly when the network cable is connected, but not when it is disconnected? And what happens when the network cable is disconnected? Do you get an error (details please) - or no error, but an empty collection as a method result?

Thank you

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07 Jun 2017 15:09 #5206 by Captain_Dash
Ok, so it should also work with the DiscoverServers method? Do you have any ideas where to start to find why it's not working?

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07 Jun 2017 15:04 #5205 by support
Have a look at the FindApplications method (an extension method to IEasyUAClient, in IEasyUAClientExtension class). You can pass in a list with e.g. just one discovery URL.

But there is something wrong if, as you wrote, "DiscoverServers [...] works only as long as the network is connected.". For a client and server on the same machine, that's not normal.

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07 Jun 2017 14:58 #5204 by Captain_Dash
can you provide a small code snippet how to make a connection for this case?

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07 Jun 2017 14:52 #5203 by support
This should work and is one of the common scenarios. Make sure that:

1) OPC UA Local Discovery Server (LDS) is installed and running
2) The OPC UA server is running and successfully registering with the LDS.

Some servers (but they are typically embedded servers where LDS is not present and makes no sense - this is obviously not your case as you are on a PC) do not register themselves with a LDS.

In addition, every OPC UA server acts is its own "mini-LDS", being able to provide info about its own endpoints. This works even without 1) and 2) above, and this functionality can also be accessed by QuickOPC (in a more complicated way), but I would not call it "server discovery", because you actually need to know at least the protocol and server port upfront. It is meant for discovery of different endpoints of an already known server.

Regards

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07 Jun 2017 14:15 #5202 by Captain_Dash
Hello,

we want to run the opc server on a pc together with a client application on the same pc. But this pc should not be connected with a network. Is it possible to discover the server by the client? I used DiscoverServers but this works only as long as the network is connected.

best regards

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