Function invocation using sockets

Hi,

I want to use sockets to communicate between two processes(P1 invokes
functions of P2). I remember seeing a request-reponse approach used in
an application. Would help if someone could let me know of a site or
location that talks of this approach.

I think the request object was divided into header and body. Not aware
of the details, would really help if could get a sample application
that uses this approach.

Thanks and Regards,
M Shetty

PS: I do not want to use RPC