Duplex in WCF

Duplex is a Two-Way Communication Process. In which, a consumer send a message to the service and the service sends a notification that the request processing has been done. It is just like that we send some command about the printing of some papers to the Printer machine. The printer machine start communication by making the connection with our machine, and start printing the paper.

1. Duplex service allows calling back some operation (function) on the client.
2. Duplex service also knows as Call Backs. 
3. All Binding does not support duplex service. 
4. Duplex communication is not standard. They are absolute Microsoft feature. 
5. wsDualHttpBinding supports duplex communication over HTTP binding. 
6. Duplex communication is possible over netTcpBinding and netNamedPipeBinding