Better Early Packet Discard
Multimedia Applications require more control at the application level as well as the network level to minimize the negative impact of the single Best Effort service offered in the Internet. The deployment of Active queue management is recommended to react to congestion before it becomes critical.
In this paper, we propose and compare some variants of EPD (Early Packet Discard), named BEPD and EPD-3 for the transmission of MPEG video streams over the Internet. We have shown by simulation that EPD, BEPD and EPD-3 increase significantly the number of transmitted I frames in comparison to the “Tail Drop” technique. BEPD improves the performance of video traffic by accepting in the queue only pictures that their reference ones have already been accepted in the queue. EPD-3 gives better results than EPD and BEPD by dropping first B pictures, then P pictures and finally I pictures.
Assured forwarding service proposed by DiffSery defines 4 independent forwarding classes. Within each of these classes, there are 3 levels of delivery which can be used to introduce some loss priority between different types of MPEG video Pictures. However, this information is not sufficient to use with EPD and its variants. We need more information about the semantic of packets. We propose and specify an extension that describes the type and the position of each packet in the video stream.
KeywordsQoS Buffer management Tail Drop EPD MPEG
- [MEH 98]Mehaoua, A., Boutaba, R., Iraqi, Y., “Partial versus Packet Video Discard”, GlobeCom’98, Sydeney, Australia, November 1998.Google Scholar
- [ROM 95]Romanow, A., Floyd, S., “Dynamics of TCP Traffic over ATM Networks”, in IEEE journal on selected Areas In Communications, May 1995.Google Scholar
- [TOU 98]Tounsi, H., Toutain, L. Kamoun, F., «Best Effort Amélioré », JDIR’98 (Journées Doctorales Informatique et Réseaux), Paris, France, Avril 1998.Google Scholar
- [TOU 99]Tounsi, H., Toutain, L. Kamoun, F., “Router Queue Management for Multimedia traffic in the Internet ”, In International Journal on Networking Information System (NIS Journal), Journal vol2 n°1 and 2, March and April 1999, Edition Hermès.Google Scholar
- [TUR 96]Turner, J., “Maintaining high throughput during oberload in ATM switches”, in Proceedings of Infocom, San Francisco, CA, April 1996.Google Scholar