HTTP/1.1 pipelining vs HTTP2 in-the-clear: Performance comparison

The average Web Page size is constantly increasing: it doubled between January 2012 and January 2015 [1]. In such a context the transport of the Internet traffic becomes very challenging. To moderate the impact of the increase of traffic on end-users' Quality of Experience (QoE), the IETF specified the protocol HTTP2, which optimizes the transfer of the HTTP1 protocol. In this paper we provide a comparison of HTTP1 and HTTP2, both in terms of functionalities and in terms of Page Download Time (PDT). As end-to-end encryption is not always required, this comparison is provided in-the-clear. To avoid any bias in the comparison, our measurements are made with the same hardware, the same software and the same transport conditions (multiplexing over a single TCP connection per domain). Based on our measurement, we show that HTTP2 always highlights better performances that HTTP1. More precisely, we observe the HTTP2 PDT remains 15% lower than HTTP1 PDT as the network delay increases. Furthermore, we observe that the ratio of HTTP2 PDT to HTTP1 PDT decreases as the packet loss increases, showing that HTTP2 is more resilient to packet loss than HTTP1.