Network Subsystem Selection
You should not go cheap with the NIC, as a high quality NIC is important for an optimized DTN host. NIC features to look for include:
- support for interrupt coalescing. For more information on the tradeoffs between rx/tx descriptors, interrupt coalescence, and L1 CPU cache size, see this article: http://patchwork.ozlabs.org/patch/348793/
- support for MSI-X
- TCP Offload Engine (TOE)
- support for zero-copy protocols such as RDMA (as implemented in RoCE or iWARP)
Note that many NICs provide dual port models, but that does not mean if you use both ports at the same time you get double the performance. Often the second port is meant to be used as a backup port. Recommended 100G options include NVIDIA/Mellanox ConnectX-5 and ConnectX-6 (200G/100G) parts, as well as the Intel E810.
A few vendors such as NVIDIA, Intel, and Broadcom also support RoCE in hardware.