+------------+      +------------+
      | IS-IS Link |      | OSPF Link  |---+
      +------------+      +------------+   |
            |               |     |        |
            |     +-------- +     |        |
            v     v               |        |
      +------------+              |        |
      | Phys. Link |<-------+     |        |
      +------------+        |     |        |
        |  ^     |          |     |        |
        |  |     +-------+  |     |        |
        v  |             v  |     v        |
      +-------------+  +-------------+     |
      | Interface 1 |  | Interface 2 |     |
      +-------------+  +-------------+     |
            ^                              |
            |                              |
            +------------------------------+