XTRA: Towards Portable Transport Layer Functions

XTRA (XFSM for Transport) aims at providing a first attempt towards a “ code-once-port-everywhere ” platform-agnostic programming abstraction tailored to the deployment of transport layer functions. XTRA’s programming abstraction not only fits SW platforms, but is specifically designed to harness, with no re-coding effort, the offloading opportunities offered by CPU-less HW boards or smart NICs. We demonstrate the viability of XTRA with three completely different implementations of the underlying execution engine (HW proof-of-concept on a NetFPGA board, User-space SW over Linux’ Open Data Plane, and NS3 emulator). Flexibility is shown via a number of example applications, ranging from a variety of congestion control algorithms, to a middlebox-type TCP proxy functionality, up to a customized “Timer-Based” (TB) TCP which leverages the native reliance of XTRA on timers, so as to produce a loss recovery operation which, despite being formalized only via a handful of code lines, performs almost comparable with the highly optimized Linux and FreeBSD implementations.