Congestion control protocols regulate sending rates to optimize application performance and network utilization. In heterogeneous networks, however, applications often have different and conflicting performance objectives, making the design of suitable utility functions a challenging task that traditionally requires extensive mathematical analysis and experimental validation.

Future network services present a significant chal-lenge for network providers due to high number and high variety of co-existing requirements. Despite many advancements in network architectures and management schemes, congested network links continue to constrain the Quality of Service (QoS) for critical applications like tele-surgery and autonomous driving. A prominent, complimentary approach consists of congestion control (CC) protocols which regulate bandwidth at the end-points before network congestion occurs. However, existing CC protocols, including recent ones, are primarily designed to handle small numbers of requirement classes, highlighting the need for a more granular and flexible congestion control solution. In this paper we introduce Hercules, a novel CC protocol designed to handle heterogeneous requirements. Hercules is based on an online learning approach and has the capability to support any combination of requirements within an unbounded and continuous requirements space. We have implemented Hercules as a QUIC module and demonstrate, through extensive analysis and real-world experiments, that Hercules can achieve up to 3.5-fold improvement in QoS compared to state-of-the-art CC protocols.

Multipath transport, as embodied in MPTCP, is deployed to improve throughput and reliability in mobile and residential access networks, with additional use-cases including spreading load in data centers and WANs. However, MPTCP is fundamentally tied to TCP Reno's legacy AIMD algorithm, and significantly lags behind the performance of modern single-path designs. Consequently, MPTCP fails to achieve high performance in many real-world environments.

Many Internet applications need high bandwidth but are not time sensitive. This motivates a congestion control "scavenger" that voluntarily yields to higher-priority applications, thus improving overall user experience. However, the existing scavenger protocol, LEDBAT, often fails to yield, has performance shortcomings, and requires a codebase separate from other transport protocols.