To the Moon and back: Are Internet bufferbloat delays really that large?

Recently, the “bufferbloat” term has been coined to describe very large queuing delays (up to several seconds) experienced by Internet users. This problem has pushed protocol designer to deploy alternative (delay-based) models to the standard (lossbased) TCP best effort congestion control. In this work, we exploit timestamp information carried in the LEDBAT header, a protocol proposed by BitTorrent as replacement for TCP data transfer, to infer the queuing delay suffered by remote hosts. We conduct a thorough measurement campaign, that let us conclude that (i) LEDBAT delay-based congestion control is effective in keeping the queuing delay low for the bulk of the peers, (ii) yet about 1% of peers often experience queuing delay in excess of 1s, and (iii) not only the network access type, but also the BitTorrent client and the operating system concurr in determining the bufferbloat magnitude.