How to OPC UA server send reversehello message to OPC UA Client?|OPC UA Standard|Forum|OPC Foundation

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How to OPC UA server send reversehello message to OPC UA Client?
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prabhakaran prabs
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05/15/2024 - 04:04
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Hi,

I have developed OPC UA SERVER application using CSharp(C#) language.

The requirement is OPC UA Server shall support reverse connection. Sever send a request to client.

My questions is -- 

When no TCP communication channel is currently opened with OPC UA client, then OPC UA server shall periodically send a ReverseHello message to OPC UA client. How to handle this one?

I have configured below details in configuration file for reverse connect.

<ServerConfiguration>

<ReverseConnect>
<Clients>
<ReverseConnectClient>
<EndpointUrl>opc.tcp://localhost:65300</EndpointUrl>
<MaxSessionCount>2</MaxSessionCount>
<Enabled>true</Enabled>
</ReverseConnectClient>
</Clients>
<ConnectInterval>15000</ConnectInterval>
<ConnectTimeout>30000</ConnectTimeout>
<RejectTimeout>60000</RejectTimeout>
</ReverseConnect>
</ServerConfiguration>

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Randy Armstrong
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05/15/2024 - 19:19
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The server cannot send a reverse hello without a socket.

If a socket breaks creates a new socket and sends a reverse hello.

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prabhakaran prabs
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05/15/2024 - 21:51
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what is the meaning of reverse hello? Is there any message is sending from server to client?

Can OPC UA server periodically send a ReverseHello message to OPC UA client?

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Randy Armstrong
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05/16/2024 - 23:18
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The ReverseHello is a message a Server sends to a Client to tell it that the socket will accept Hello requests.

The ReverseHello is sent once each time a Server connects to a Client.

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prabhakaran prabs
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05/16/2024 - 23:22
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How to configure,   server periodically send a ReverseHello message to OPC UA client?

I have used below config

<ServerConfiguration>

<ReverseConnect>
<Clients>
<ReverseConnectClient>
<EndpointUrl>opc.tcp://localhost:65300</EndpointUrl>
<MaxSessionCount>2</MaxSessionCount>
<Enabled>true</Enabled>
</ReverseConnectClient>
</Clients>
<ConnectInterval>15000</ConnectInterval>
<ConnectTimeout>30000</ConnectTimeout>
<RejectTimeout>60000</RejectTimeout>
</ReverseConnect>
</ServerConfiguration>

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Randy Armstrong
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05/20/2024 - 07:58
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Should cause the server to maintain 2 open sockets with the client and if the client goes down the server will retry on a 15s cycle.

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prabhakaran prabs
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05/20/2024 - 21:58
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you mean to say, OPC UA Sever will use ConnectInterval parameter for sending reverse hello message periodically to OPC UA Client right?

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Randy Armstrong
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05/21/2024 - 09:25
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That is what should happen when the client is down. When the client is running it creates 2 sockets.

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