How Xen really works

+------------ X E N ----------------+
|                                   |
|  +---DOM 0 ---+   +--- DOM U ---+ |
|  |            |NET|             | |
|  |            |<=>|             | |
|  |            |   |             | |
|  |            |   |             | |
|  +------------+   +-------------+ |
|     ^                             |
|     |                             |
|     V                             |
+-----------------------------------+
   Hardware