Abstract-Reliability is critical to a variety of network applications. Unfortunately, due to lack of QoS support across ISP boundaries, it is difficult to achieve even two 9s (99%) reliability in today's Internet. In this paper, we propose SmartTunnel, an end-to-end approach to achieving reliability. A SmartTunnel is a logical point-to-point tunnel between two end points that spans multiple physical network paths. It achieves reliability by strategically allocating traffic onto multiple paths and performing FEC coding. Such an end-to-end approach requires no explicit QoS support from intermediate ISPs, and is therefore easy to deploy in today's Internet. To fully realize the potential of SmartTunnel, we analytically derive near-optimal traffic allocation schemes that minimize loss rates. We extensively evaluate our approach using trace-driven simulations, ns-2 simulations, and experiments on PlanetLab. Our results clearly demonstrate that SmartTunnel is effective in achieving high reliability.

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A more generalized model of a beam resting on a tensionless Reissner foundation is presented. Compared with the Winkler foundation model, the Reissner foundation model is a much improved one. In the Winkler foundation model, there is no shear stress inside the foundation layer and the foundation is assumed to consist of closely spaced, independent springs. The presence of shear stress inside Reissner foundation makes the springs no longer independent and the foundation to deform as a whole. Mathematically, the governing equation of a beam on Reissner foundation is sixth order differential equation compared with fourth order of Winkler one. Because of this order change of the governing equation, new boundary conditions are needed and related discussion is presented. The presence of the shear stress inside the tensionless Reissner foundation together with the unknown feature of contact area/length makes the problem much more difficult than that of Winkler foundation. In the model presented here, the effects of beam dimension, gap distance, loading asymmetry and foundation shear stress on the contact length are all incorporated and studied. As the beam length increases, the results of a finite beam with zero gap distance converge asymptotically to those obtained by the previous model for an infinitely long beam.