Hi Browser,
Generally speaking, InfiniBand protocol provides the underlying transport for many other ULPs (like IPoIB IP Over IB).
over the basic transport (InfiniBand) people can run nativly RDMA applications (directly attaching to the verbs) and over the ULPs can run other protocols applications like IP, NFS and others.
the IPoIB adapter/interface you see in your OS (may it be Windows or Linux) is the standard interface provided for IP applications (and hence, has an IP address). if you shut it down, you can still run native IB (RDMA) applications.
ibping is one of those native IB applications. it doesn't need IP information to communicate. it uses IB addressing like LID and GUID.