+------+    +------+
                         | ISP1 |    | ISP2 |
                         +---+--+    +--+---+     
                             |          |     Service Providers
       ......................|..........|.......................
                             |          |     Enterprise Network
                         +---+--+    +--+---+
                         | CPE1 |    | CPE2 |
                         +------+    +------+
 
                               ... (Internal Network)