Wcf service client communication?

Question

Hi everyone I need help.In my project wcf service should have ability to communicate wit client and send him some requests.There is one service but clients can be more and I need to send request to specific client.I'm wondering if I can implement that in some other way then duplex,request-reply,msmq. Both service and client are on the same computer,so is there any other type of communication that I can use.
If you know some examples(code) please post me link to it.
Thanks in advance