Standard transport protocols like TCP operate as a blind, FIFO conveyor belt for data, a model that is increasingly suboptimal for latency-sensitive and interactive applications. This paper challenges this model by introducing CATS (Conductor-driven Asymmetric Transport Scheme), a framework that provides TCP with the semantic awareness necessary to prioritize critical content. By centralizing scheduling intelligence in a transport-native "Conductor", CATS significantly improves user-perceived performance by delivering essential data first. This architecture directly confronts a cascade of historical performance workarounds and their limitations, including the high overhead of parallel connections in HTTP/1.1, the transport-layer Head-of-Line blocking in HTTP/2, and the observed implementation heterogeneity of prioritization in HTTP/3 over QUIC. Built upon TCP BBR, our ns-3 implementation demonstrates this principle by reducing the First Contentful Paint by over 78% in a representative webpage download configured as a deliberate worst-case scenario, with no penalty to total page load time compared to the baseline.

翻译：诸如TCP等标准传输协议以盲目的FIFO传送带模式处理数据，这种模式对延迟敏感和交互式应用日益不优。本文通过引入CATS（导体驱动非对称传输方案）挑战了这一模式，该框架为TCP提供了必要的语义感知能力以优先传输关键内容。通过将调度智能集中到传输原生的“导体”中，CATS通过优先交付关键数据显著改善了用户感知性能。该架构直面一系列历史性能优化方案及其局限性，包括HTTP/1.1中并行连接的高开销、HTTP/2中传输层队头阻塞问题，以及HTTP/3 over QUIC中优先级机制的实际实现异质性。基于TCP BBR构建的ns-3实现验证了该原理：在代表性网页下载场景中（配置为刻意的最坏情况），首次内容绘制时间减少超过78%，且与基线相比总页面加载时间未受任何影响。