Per-Flow Throughput Fairness in Ring Aggregation Network with Multiple Edge Routers

Ring aggregation networks are often employed by network carriers because of their efficiency and high fault tolerance. A fairness scheme is required in ring aggregation to achieve per-flow throughput fairness and bufferbloat avoidance, because frames are forwarded along multiple ring nodes. N Rate N + 1 Color Marking (NRN + 1CM) was proposed to achieve fairness in ring aggregation networks consisting of Layer-2 Switches (SWs). With NRN + 1CM, frames are selectively discarded based on color and the frame-dropping threshold. To avoid the accumulation of a queuing delay, frames are discarded at upstream nodes in advance through the notification process for the frame-dropping threshold. However, in the previous works, NRN + 1CM was assumed to be employed in a logical daisy chain topology linked to one Edge Router (ER). The currently available threshold notification process of NRN + 1CM cannot be employed for ring networks with multiple ERs. Therefore, this paper proposes a method for applying NRN + 1CM to a ring aggregation network with multiple ERs. With the proposed algorithm, an SW dynamically selects the dropping threshold to send in order to avoid excess frame discarding. The performance of the proposed scheme was confirmed through computer simulations.

A New Real-Time Video Watermarking Scheme Based on Mutative Area

A new algorithm of video watermarking based on changed area is studied in this paper. We propose a method to located area which pixels change greatly from three successive frames of uncompressed video by using three-frame differencing. Then we choose the region where changes drastically to embed watermark by using the Quantization Modulation algorithm in DCT coefficients. In order to have a good performance on video quality and embed more information, we divided the binary watermark into two parts which obtain a logistic Arnold transform before being embedded. The experimental results indicates that the proposed scheme has a good performance to frame dropping, frame cropping, frame rating, Gaussian noising, MPEG2 compression, etc. and it has a advantage on little degrading the video quality.