Hi all, First, I am sorry because it's not a question related to twisted. But since twisted is a networking programming framework, you might be interested. Some of my colleagues have a view that a net work server should be split to small parts with different functions, either with processes communicating with socket, or with threads talking on message queues. Their points are these: 1. Each part could it's own state-machine, thus we could split big state-machines to decoupled small ones. 2. It makes a pipe line that could handle some requests at the same time without introducing lock problem of threading. Just like how CPU use pipe line to improve performance. 3. It resembles a micro-kernel system which is supposed to have better availability. As far as I know, some networking device manufactures use this model to implement their routers or switches. but I have never heard any examples besides that. As twisted book says, most networking application use one of these 3 modes: 1. handle each connection in a separate operating system process, in which case the operating system will take care of letting other processes run while one is waiting; 2. handle each connection in a separate thread1 in which the threading framework takes care of letting other threads run while one is waiting; or 3. use non-blocking system calls to handle all connections in one thread. (Like twisted or lib-event or just select) After considering for a while, I thought there are some faults in the multiple parts model: 1. Writing code to handle message is much more tedious than just doing function calls 2. It's not very easy to make a pipe line works fine. OK, hope I made myself clear. Since most of you who are reading this mail list , are experienced networking programmers, I think you might give some insight comments.