Characterizing SPDY over High Latency Satellite Channels

Abstract

The increasing complexity of Web contents and the growing diffusion of mobile terminals, which use wireless and satellite links to get access to the Internet, impose the adoption of more specialized protocols. In particular, we focus on SPDY, a novel protocol introduced by Google to optimize the retrieval of complex webpages, to manage large Round Trip Times and high packet losses channels. In this perspective, the paper characterizes SPDY over high latency satellite links, especially with the goal of understanding whether it could be an efficient solution to cope with performance degradations typically affecting Web 2.0 services. To this aim, we implemented an experimental setup , composed of an ad-hoc proxy, a wireless link emulator, and an instrumented Web browser. The results clearly indicate that SPDY can enhance the performances in terms of loading times, and reduce the traffic fragmentation. Moreover, owing to its connection multiplexing architecture, SPDY can also mitigate the transport layer complexity, which is critical when in presence of Performance Enhancing Proxies usually deployed to isolate satellite trunks.

Performance analysis of next generation web access via satellite

“…This paper complements the analysis on HTTP/2 over satellite carried out in by evaluating the protocol across a wider range of scenarios, including cases with PEPs and cases where PEPs were unable to offer benefit (e.g. with encrypted tunnels).…”

“…Our results confirm previous analysis that HTTP/2 offers better performance with respect to HTTP/1.1 provided that the system is fine‐tuned to support the protocol. In , for example, it was observed that multiplexing the entire web connection over a single connection can be a disadvantage when the connection suffers wireless loss. However, this performance reduction can be compensated for by using an appropriate scheduling discipline and countermeasures for the wireless errors.…”

“…This higher path delay can expose inefficiencies in protocol design/usage -and as for other services with a higher path delay has led to common use of protocol accelerators (sometimes known as Protocol Enhancing Proxies, PEPs [17]) with HTTP/1.1. This is therefore a helpful test case for HTTP/2 and helps answer the question as to whether the performance enhancements in the new protocol are sufficient to eliminate the need for PEPs in satellite networks or whether new methods will be needed.This paper complements the analysis on HTTP/2 over satellite carried out in [6,[18][19][20] by evaluating the protocol across a wider range of scenarios, including cases with PEPs and cases where PEPs were unable to offer benefit (e.g. with encrypted tunnels).…”

Using SPDY to improve Web 2.0 over satellite links

“…In this perspective, SPDY would also be able to improve the access to Web 2.0 via satellite channels. In fact, our past works considering mixed wireless local area network/satellite accesses through emulated settings indicate non‐negligible performance gains . Additionally, SPDY is a very mature technology, thus offering a stable benchmark of the fast evolving and still uncertain HTTP 2.0–Web 2.0 panorama.…”