________
                                          +------------+      /
                                          |            |      |
                            +-------------+ Provider 1 +------+
                            |             |            |      |
            VLan1----+------+-------+     +------------+      |
                     |     if1      |                         |
                     |              |                         |
            VLan2----+ Linux router |                         |     Internet
                     |              |                         |
                     |     if2      |                         |
            VLan3----+------+-------+     +------------+      |
                            |             |            |      |
                            +-------------+ Provider 2 +------+
                                          |            |      |
                                          +------------+      \________