POSTER: Implementation of TCP SEARCH in FreeBSD and Evaluation on a Satellite Network

TCP’s slow start phase is particularly inefficient over most wireless networks, especially high-latency, high-bandwidth paths such as satellite networks, often exiting too early or too late (after packet loss). To address this, the Slow start Exit At CHokepoint (SEARCH) algorithm is designed to improve exit decisions during slow start by analyzing delivery trends across sliding RTT-based windows. This paper presents a first implementation of SEARCH in the FreeBSD kernel using FreeBSD’s modular congestion control framework. We evaluate our implementation on a testbed with an actual GEO satellite link with ~600 ms RTT and 150 Mb/s capacity. Preliminary results show that SEARCH exits slow start more effectively than HyStart and HyStart++, achieving higher throughput and better utilization.