This is fairly basic question about K2 architecture.

In production we have a K2 server which runs the Blackpearl window service and also the K2 web sites.  We have a seperate server that runs our main application web site.  The main web server uses the K2 API calling methods on local DLLs on the server.  What I don't understand is how the K2 DLL communicate with the K2 Server.  Is there a custom RPC mechanism between the K2 Host Server process and the DLLs ??

We are having performance problems with K2 where it can take 10 seconds to create a process instance and on other occcasions the main web server gets no response from K2 at all.  Trying to understand what talks to what and how is our current plan to trying and fix this.