MCQUIC - A Multicast Extension for QUIC

TL;DR

MCQUIC, a multicast extension to the QUIC transport protocol which addresses many of these challenges of multicast delivery by providing encryption and integrity verification of packets distributed over multicast, along with automatic unicast fallback.

Abstract

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.

Figures (5)

• Figure 1: MCQUIC combines QUIC unicast connections with multicast channels to allow for scalable and robust delivery of mass media content. Schematic overview of a multicast source, a Fan-Out server and two clients using MCQUIC. The orange connection represents multicast, used to carry big data packets such as video frames, while the connections in the purple and blue represent unicast connections, used only for control. The multicast source does not have to be co-located with the server handling the unicast connections. Instead, a fan-out connection, displayed in green, can be used to allow for load balancing.
• Figure 2: Simplified flow diagram of an MCQUIC connection.
• Figure 3: Bandwidth usage for total number of viewers of a 4K live video. Both native multicast and MCQUIC with multicast integrity remain at a constant bandwidth while MCQUIC with unicast integrity scales around 1.5 magnitudes better than full unicast video delivery.
• Figure 4: Overhead bandwidth in MBit/s per client for different scenarios.
• Figure 5: Overhead bandwidth in MBit/s per client for different scenarios.