Deferred discard for improving the quality of video sent across congested networks

Video already constitutes more than half of Internet traffic, and is expected to expand to over 80% of Internet traffic by 2016. The dominance of video traffic justifies router features that optimise performance when video loads are high, in particular features that can deal with the congestion that video can create. In this paper, we exploit a characteristic of video, namely that video streams consist of recurring patterns of packets of varying importance, to create a new Deferred Discard queue management scheme. We simulated different queue management schemes with four test videos and measured their performance in terms of the average picture signal to noise ratio (PSNR). In the range of PSNRs from 18.5 for best-effort service to 33.1 for ideal service, Differentiated Services (Diffserv) provided a PSNR of 22.1, while Deferred Discard improved the PSNR to 26.8 when used alone, and to 27.9 when combined with Diffserv.