+------------------------------------------+
         |         Integrated Router/Bridge         |

         +-------+        +--------+        +-------+
         |       |    IRB1|   L3   |IRB2    |       |
 H1 -----+  BD1  +--------+Routing +--------+  BD2  +------H3
         |       |        |Instance|        |       |
 H2 -----|       |        |        |        |       |
         +-------+        +--------+        +-------+
    |___________________|            |____________________|
               LAN1                              LAN2