Mass live content, such as world cups, the Superbowl or the Olympics, attract audiences of hundreds of millions of viewers. While such events were predominantly consumed on TV, more and more viewers follow big events on the Internet, which poses a scalability challenge: current unicast delivery over the web comes with large overheads and is inefficient. An attractive alternative are multicast-based transmissions, however, current solutions have several drawbacks, mostly related to security and privacy, which prevent them from being implemented in browsers. In this paper we introduce a multicast extension to QUIC, a widely popular transport protocol standardized by the IETF, that solves several of these problems. It enables multicast delivery by offering encryption as well as integrity verification of packets distributed over multicast and automatic unicast fallback, which solves one of multicasts major obstacles to large scale deployment. It is transparent to applications and can be easily utilized by simply enabling an option in QUIC. This extension is soley focused on the transport layer and uses already existing multicast mechanisms on the network layer.

翻译：大型直播内容，如世界杯、超级碗或奥运会，吸引了数亿观众。虽然此类活动以往主要通过电视观看，但越来越多的观众选择在互联网上观看大型赛事，这带来了可扩展性挑战：当前基于网络的单播传输方式开销巨大且效率低下。基于多播的传输是一种有吸引力的替代方案，然而现有解决方案存在若干缺陷，主要涉及安全性和隐私问题，导致其无法在浏览器中实现。本文提出了一种针对QUIC的多播扩展方案，QUIC是由IETF标准化的广受欢迎传输协议。该扩展通过提供多播分发数据包的加密与完整性验证，以及自动单播回退机制，解决了多播大规模部署的主要障碍之一。该扩展对应用程序透明，仅需在QUIC中启用选项即可轻松使用。此扩展完全聚焦于传输层，并利用网络层已有的多播机制。