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