This paper presents three mathematical formulations for designing robust two-layer networks carrying elastic traffic. The formulations differ in the way flow reconfiguration is performed in the case ...of link failures. An iterative algorithm to solve the problems is given and a numerical study is provided comparing the effectiveness of the three reconfiguration mechanisms. The formulations can be applied for designing Next Generation Internet (NGI) core networks with the two-layer, IP-over-WDM, structure.
On efficient max-min fair routing algorithms Pioro, M.; Nilsson, P.; Kubilinskas, E. ...
International Symposium on Computers and Communications ISCC 2003,Kemer-Antalya, Turkey,2003-06-30 - 2003-07-03,
2003
Conference Proceeding, Book Chapter
In the paper, we consider the problem of routing and bandwidth allocation in networks that support elastic traffic. We assume that the bandwidth demand between each source-destination (S-D) pair is ...specified in terms of a minimum and maximum value, and a set of flows between each S-D pair is allowed to realize these demands. (We say that a set of flows realizes the demand associated with an S-D pair, if the sum of the bandwidths allocated to these flows is greater than the minimum value assumed for the demand of that S-D pair). In this setting, we show that routing and bandwidth allocation can be formulated as an optimization problem, where network utilization is to be maximized under capacity and the widely used max-min fairness constraints. We describe three different algorithms to solve variants of this problem. The most important one, an efficient, original algorithm assuming multipath routing is studied in detail and illustrated with a numerical example.
Measurements of direct photon production in p + Pb and p + C collisions at root(NN)-N-s = 17.4 GeV are presented. Upper limits on the direct photon yield as a function of p(T) are derived and ...compared to the results for Pb + Pb collisions at root(NN)-N-s = 17.3 GeV. The production of the eta meson, which is an important input to the direct photon signal extraction, has been determined in the eta -> 2 gamma channel for p + C collisions at root(NN)-N-s = 17.4 GeV. (c) 2012 Elsevier B.V. All rights reserved.
Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at root s(NN) = 17.4 GeV at midrapidity (2.3 less than or similar to eta(lab)less than or similar to 3.0) over the ...range 0.7 less than or similar to p(T)less than or similar to 3.5 GeV/c. The spectra are compared to pi(0) spectra measured in Pb+Pb collisions at root s(NN) = 17.3 GeV in the same experiment. For a wide range of Pb+Pb centralities (N-part less than or similar to 300), the yield of pi(0)'s with p(T)greater than or similar to 2 GeV/c is larger than or consistent with the p+C or p+Pb yields scaled with the number of nucleon-nucleon collisions (N-coll), while for central Pb+Pb collisions with N-part greater than or similar to 350, the pi(0) yield is suppressed.
The notion of proportional fairness has recently gained considerable interest as a potential means for a fair allocation of bandwidth between the end nodes of demands in the networks carrying elastic ...traffic. The issue of proportionally fair allocation of bandwidth for the nominal state of the network has been studied before, both in the capacitated (link capacities given) and the uncapacitated (link capacities are also subject to optimisation) cases. In the presented paper, we address a more complicated uncapacitated problem - optimisation of link capacities for a proportionally fair network robust to failures. We formulate a relevant optimisation problem and propose efficient solution algorithms. Efficiency of the algorithms is illustrated with numerical examples including large networks. The design approach is applicable to IP/MPLS networks based on leased transmission capacity.
PDF
