To improve efficiency of systems operating on internet protocol (IP) over Infiniband (IB) networks, mechanisms are provided for operating a system including a plurality of nodes, each connected to at least one IB switch. A determination is made whether an IP address of a node is included in a first level of a global ARP cache. An IP over IB GUID corresponding to the IP address of the node is identified. A determination is made whether an entry in a second level of the global ARP cache includes the identified IP over IB GUID of the node, and corresponding the IP over IB GUID of the node to IB address information of the node.