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We propose a theoretical analysis of a novel source routing scheme called XSR. XSR uses linear encoding operation to both (1) build the path labels of unicast and multicast data transfers; (2) perform fast computational efficient routing decisions compared to standard table lookup procedure without any packet modification all along the path. XSR specifically focuses on decreasing the computational complexity of forwarding operations. This allows packet switches (e.g, link-layer switch or router) to perform only simple linear operations over a binary vector label that embeds the path. We provide analytical proofs demonstrating that XSRs efficiently compute a valid unicast or multicast path label over any finite fields F 2 w . Furthermore, we show that this path label can be used for both the forward and return unicast paths, unlike other source routing algorithms that require recomputing a label for the return path. Compared to recent approaches based on modular arithmetic, XSR computes the smallest label possible and presents strong scalable properties, allowing it to be deployed over any kind of core vendor or datacenter networks. [ABSTRACT FROM AUTHOR]

Satellite transmissions can suffer from high channel impairments, especially on the link between a satellite and a mobile end user. To cope with these errors, physical and link-layer reliability schemes have been introduced at the price of an increased end-to-end delay seen by the transport layer [for example, Transmission Control Protocol (TCP)]. By default, the TCP enables delayed acknowledgment (DelAck) that might increase the end-to-end delay when performing over satellite link-layer recovery schemes. As a matter of fact, even if this option enables decreasing the feedback path load and the stack processing overhead, it might be counterproductive in a satellite context. This motivates the present paper, which aims to quantify the impact of such a TCP option in the context of low Earth orbit satellite constellations. Several simulation measurements are performed with two well-deployed TCP variants, and it is shown that DelAck should be disabled when used over link-layer Hybrid Automatic Repeat Request schemes, particularly when these schemes enable reordering the buffer. [ABSTRACT FROM AUTHOR]

Abstract: The behaviour of the TCP AIMD algorithm is known to cause queue length oscillations when congestion occurs at a router output link. Indeed, due to these queueing variations, end-to-end applications experience large delay jitter. Many studies have proposed efficient active queue management (AQM) mechanisms in order to reduce queue oscillations and stabilize the queue length. These AQM attempt to improve the random early detection (RED) model. Unfortunately, these enhancements do not react in a similar manner for various network conditions and are strongly sensitive to their initial setting parameters. Although this paper proposes a solution to overcome the difficulties of configuring the RED parameters by using a Kohonen neural network model; another goal of this study is to investigate whether cognitive intelligence could be placed in the core network to solve such stability problem. In our context, we use results from the neural network area to demonstrate that our proposal, named Kohonen-RED (KRED), enables a stable queue length without complex parameters setting or passive measurements to obtain a correct configuration. [ABSTRACT FROM AUTHOR]

Abstract: This paper introduces a redundancy adaptation algorithm based on an on-the-fly erasure network coding scheme named Tetrys in the context of real-time video transmission. The algorithm exploits the relationship between the redundancy ratio used by Tetrys and the gain or loss in encoding bit rate from changing a video quality parameter called the Quantization Parameter (QP). Our evaluations show that with equal or less bandwidth occupation, the video protected by Tetrys with redundancy adaptation algorithm obtains a PSNR gain up to or more than 4dB compared to the video without Tetrys protection. We demonstrate that the Tetrys redundancy adaptation algorithm performs well with the variations of both loss pattern and delay induced by the networks. We also show that Tetrys with the redundancy adaptation algorithm outperforms traditional block-based FEC codes with and without redundancy adaptation. [Copyright &y& Elsevier]