I read this Article and I thought I write a little ping Service (Both Service and Client can ping). however, when I use
[ServiceBehavior(InstanceContextMode=InstanceContextMode.PerSession,
ConcurrencyMode = ConcurrencyMode.Multiple)]
My ping service only creates one instance. But I want multiple instances. My callback interface is saved in a private but it is overwritten because when the clients register, they register to one instance and not different. Is that Bad design in my case or why does wcf only create one instance?