There are a couple implementations of userland ip/tcp out there. As I recall at least one or two are fairly direct ports of a BSD network stack in to a library.

There are a couple implementations of userland ip/tcp out there. As I recall at least one or two are fairly direct ports of a BSD network stack in to a library. These pair up with concepts like intels dpdk to move networking closer to the business logic. Here are some slides for one version: http://www.bsdcan.org/2014/schedule/attachments/260_libuinet_bsdcan2014.pdf http://www.bsdcan.org/2014/schedule/attachments/260_libuinet... Edit: with regards to motivation it's always been something along the lines of a network appliance that I've seen. The mainline linux network stack is more than capable of doing many millions of packets per second over hundreds of thousands of concurrent streams. The network stack will not be the limitation in something like batch processing.