国家自然科学基金(62202473, 61932016); 国家杰出青年科学基金(61825204); 北京高校卓越青年科学家计划(BJJWZYJH01201910003011)
Internet传输层协议需要依赖于确认(ACK)机制提供的反馈信息, 实现拥塞控制和可靠传输等功能. 以Internet传输协议演化的历史为线索, 回顾传输控制领域中的确认机制, 并讨论现有确认机制中需要解决的问题; 基于“类型-触发条件-信息” 三要素, 提出按需确认机制及其设计原则, 重点分析确认机制和拥塞控制、丢包恢复等传输协议子模块之间的耦合关系; 结合设计原则, 详细阐述一种可行的按需确认机制实现——TACK机制, 并对相关概念进行系统的、深入的分析和澄清. 最后结合按需确认机制面临的挑战, 给出几个有意义的研究方向.
Internet transport-layer protocols rely on the feedback information provided by the acknowledgment (ACK) mechanism to achieve functions such as congestion control and reliable transmission. According to the evolution of Internet transmission protocols, the ACK mechanisms of transmission control are reviewed. The unsolved problems among the mechanisms are discussed. Based on the elements of “type-trigger-information”, the ACK mechanism based on demand and its design principle are proposed, and the coupling relationship between the ACK mechanism and other transmission protocol submodules (e.g., congestion control, packet loss recovery, etc.) is emphatically analyzed. Subsequently, according to the design principle, the TACK mechanism, a feasible ACK mechanism based on demand, is elaborated, and relative concepts are systematically clarified. Finally, several meaningful research directions are provided according to the challenges encountered by the ACK mechanism based on demand.