InfiniBand is widely accepted as a high performance networking technology for datacenters and HPC clusters. It uses the Remote Direct Memory Access (RDMA) where communication tasks that are typically assigned to CPUs are offloaded to the Channel Adapters (CAs), resulting in a significant increase of the throughput and reduction of the latency and CPU load. In this paper, we make an introduction to InfiniBand and IP over InfiniBand (IPoIB), where the latter is a protocol proposed by the IETF to run traditional socket-oriented applications on top of InfiniBand networks. We also evaluate the performance of InfiniBand using different transport protocols with several benchmarking tools in a testbed. For RDMA communications, we consider three transport services: (1) Reliable Connection, (2) Unreliable Connection, and (3) Unreliable Datagram. For UDP and TCP, we use IPoIB. Our results show significant differences between RDMA and IPoIB communications, encouraging the coding of new applications with InfiniBand verbs. Also, it is noticeable that IPoIB in datagram mode and in connected mode have similar performance for small UDP and TCP payload. However, the differences get important as the payload size increases.