Basic TCP/IP Host

   ----------------------------
   |    network applications  |
   |                          |
   |...  \ | /  ..  \ | /  ...|
   |     -----      -----     |
   |     |TCP|      |UDP|     |
   |     -----      -----     |
   |         \      /         |
   |         --------         |
   |         |  IP  |         |
   |  -----  -*------         |
   |  |ARP|   |               |
   |  -----   |               |
   |      \   |               |
   |      ------              |
   |      |ENET|              |
   |      ---@--              |
   ----------|-----------------
             |
 ------------o---------
             Ethernet Cable