So far, large computing clusters consisting of several thousand machines have been constructed by connecting nodes together using interconnect technologies as e.g. Ethernet, Infiniband or Myrinet. The authors propose an entirely new architecture called Tightly Coupled Cluster (TCCluster) that instead uses the native host interface of the processors as a direct network interconnect. This approach offers higher bandwidth and much lower communication latencies than the traditional approaches by virtually integrating the network interface adapter into the processor. Their technique neither applies any modifications to the processor nor requires any additional hardware.