what is the fast way do connect two PCs over internet ?

I've to connect two PCs over internet.

First pc (PCA) is the client.
Second pc (PCB) is the server.

(PCA) send a request to (PCB)
and (PCB) responses to request.

(PCA) must be able to send a very
big number of requests for seconds.

The request and response are true ANSI text strings.

What is the best way to do this ?

Thank you very much

Silverio Diquigiovanni...