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Promote the Use of Explicit Delay Control

Xiaoyuan Gu, Dirk Markwardt, Lars Wolf
Institute of Operating Systems & Computer Networks, Technische Universit¨at Braunschweig M¨uhlenpfordtstr. 23, Braunschweig 38106, Germany

Abstract—The Internet is undergoing changes of its trafficmix, with the IP-based interactive multimedia applicationsgaining momentum. According to studies, UDP-based multimediatraffic has in recent years risen to above 25% of theoverall Internet traffic volume, as compared to only 5% adecade ago. To these delay sensitive real-time interactivemultimedia applications, out of delay boundary packetsare usually obsolete. However the current Internet Protocollacks a way to control the lifetime of the packets effectively.In this paper, we propose the Explicit Delay Control (EDC)as a viable packet lifetime control mechanism designed forsuch purpose. It uses an embedded Maximum TolerableDelay (MTD) field in an IPv4 option. The value of MTD isdetermined by taking the application specific delay bound,measured round-trip-time, and the estimations of the pathpropagation delay and transmission delay into account. Ateach network node, the MTD is deducted by the singlehopdelay. Packets that expire their lifetime are discardedand non-congestion related delay losses are signaled to thesender to reduce inaccuracy in delay estimations and toadapt to path changes. We implemented EDC in the Linuxkernel. Our evaluation has shown that EDC can ensure the“legality” of the packets, reduce the waste of bandwidthand processing time in the networks, and help to alleviatecongestions.

Index Terms—packet lifetime control, multimedia, networkentertainment, quality of service

Cite: Xiaoyuan Gu, Dirk Markwardt, Lars Wolf, "Promote the Use of Explicit Delay Control," Journal of Communications, vol. 1, no. 3, pp. 41-52, 2006.