PCI Express (PCIe), the I/O interconnect of choice in today's single host computing platform, is being enhanced to support features that include I/O virtualization and processor-coprocessor interconnect. Host-to-host communication, however, is regarded as beyond the scope of PCIe. As such, the model in today's multi-compute platforms is to utilize PCIe for communication between the host(s) and the I/O subsystem while a dedicated clustering interconnect such as Infiniband or Ethernet is used for host-to-host communication.

The Dolphin Express solution (i.e. Dolphin's enhanced PCIe hardware and accompanying software) addresses the shortcoming of host-to-host communication in PCIe in a cost-effective manner. To the best of our knowledge, these products provide an industry first solution of using a PCIe-based switch fabric to seamlessly integrate both IO and clustering capabilities-- thereby obviating the need for an additional clustering interconnect.

As a first step towards providing a full-fledged clustering solution, we have provided support for TCP/IP protocol over PCIe (IPoPCIe). Based on benchmarking results, IPoPCIe was able to achieve performance that was on par or better than that of a 10GigE NICfs. On a 2-node system connected using a switch, IPoPCIe shows an end-to-end application latency of ~14us and bandwidth of up to 1270MB/s.

Though the results are promising, the performance of IPoPCIe is greatly influenced by overheads associated with TCP/IP stack processing. Hence, work is ongoing on supporting the TCP/IP sockets interface but without incurring the traditional TCP/IP stack overheads. This would utilize the full potential of the underlying Dolphin Express hardware and lead to further reduction in latency, lower CPU utilization and increased bandwidth.