1)The first of the traditional approaches is to have a single listener thread that accepts all incoming connections and then passes these off to other threads for processing. The problem with this approach is that the listening thread can become a bottleneck in extreme cases. In early discussions on SO_REUSEPORT, Tom noted that he was dealing with applications that accepted 40,000 connections per second. Given that sort of number, it's unsurprising to learn that Tom works at Google.

2)The second of the traditional approaches used by multithreaded servers operating on a single port is to have all of the threads (or processes) perform an accept() call on a single listening socket in a simple event loop of the form:

    while (1) {
        new_fd = accept(...);
        process_connection(new_fd);
    }