+----------------+
     | Client Browser |
     +----------------+
        |^     ^ |^
        ||    /  ||
    [A] ||   /   || [C*]
        ||  /    ||
        v| /(B2) v|
+----------+   +-----------+
| HTTP Svr |   | HTTPS Svr |
+----------+   +-----------+
     (B1) \     ^ (C1)
           v _ /
            / \
           |\_/|
           |   |
            \_/