The maximum available quality in the system is limitedby the number of descriptions that are delivered from thesource to all the peers in level 1. This quality is determinedby (i) the aggregate throughput from the source to all of itschild peers, and (ii) the utilization of source’s access linkbandwidth. The aggregate throughput from the source dependson its outgoing bandwidth as well as its outgoing degree whichshould be determined by the bandwidth-degree condition. Weintroduce the term diffusion rate as the rate of delivery fornew bits from source to level 1. Ideally, the diffusion rateshould be equal to the aggregate throughput from the sourceand the number of copies among delivered packets to level1 should be fairly even. Satisfying these two conditions atlevel 1 ensures proper behavior across other levels since thepackets are simply multiplied by degree as they are pulledtowards lower levels. In practice, the following two factors canreduce the diffusion rate or unbalance the number of copiesfor delivered packets: (i) the independent packet scheduling bypeers in level 1, and (ii) the random loss of delivered packetsto level 1
đang được dịch, vui lòng đợi..
