Adaptive Early Packet Discarding Scheme to Improve Network Delay Characteristics of Real-Time Flows

Kazumi KUMAZOE  Masato TSURU  Yuji OIE  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.9   pp.2481-2493
Publication Date: 2007/09/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.9.2481
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
queuing delay,  early packet discarding,  real-time application,  MTQ,  QTL,  

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The performance of a real-time networked application can be drastically affected by delays in packets traversing the network. Some real-time applications impose limits for acceptable network delay, and so a packet which is delayed longer than the limit before arriving at its destination is worthless to the flow to which the packet belongs. Not only that, but the rejected packet is also damaging to the quality of other flows in the network, because it may increase the queuing delay for other packets. Therefore, this paper proposes an adaptive scheme using two mechanisms, in which packets experiencing too great a delay are discarded at intermediate nodes based on the delay limit for the application and the delay experienced by each packet. This earlier discarding of packets is expected to improve the overall delay performance of real-time flows competing for network resources when the network is congested. An extensive simulation is conducted, and the results show that the scheme has great potential in improving the delay performance of real-time traffic in both homogeneous and heterogeneous environments in terms of traffic volume and application delay requirements.