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：大规模实时内容（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，但越来越多的观众通过互联网关注大型赛事，这带来了可扩展性挑战：当前基于单播的网页传输开销大且效率低。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，主要涉及安全与隐私问题，导致其无法在浏览器中实现。本文提出了QUIC（一种由IETF标准化的广泛流行的传输协议）的多播扩展，解决了上述部分问题。该扩展通过提供加密功能、多播分发数据包的完整性验证以及自动单播回退机制，实现了多播传输，从而解决了多播大规模部署的主要障碍之一。它对应用层透明，仅需在QUIC中启用相应选项即可轻松使用。该扩展完全聚焦于传输层，并利用网络层已有的多播机制。