A large variety of access network technologies and architectures that provide wide service portfolio to the customer are available for the network operators. Each of the potential access network architectures and technologies varies in complexity, network functionality, services supported and overall network costs. A detailed comparison of the economic viability of different access network scenarios is crucial for operators due to the high cost of this network segment. This paper identifies all essential elements of a general framework for the techno-economic analysis of different access network technologies and architectures, as well as describes some specific issues/problems related to the techno-economic evaluation of next generation (NG) access networks. The goal is to have at operator's disposal a methodology allowing the techno-economic comparison of the proposed access network solutions and their introduction/rollout.

We present a topology design methodology for broadband (FTTx) access networks. The calculations are based on real geographic data (digital maps) and infrastructural information of the targeted area, using detailed and realistic cost models in order to provide results of practical interest. The developed heuristics offer low time consumption and nearly optimal solutions for the highly complex problem of minimal cost network deployment, due to the properly chosen and customized heuristic algorithms for the various network technologies. We review the specific properties of the FTTx network technologies, present a formal representation of the problem including a detailed cost function and network model and discuss complexity issues. The various solution techniques are presented along with case studies of real-life scenarios in order to show the potential of the methodology. The developed heuristic algorithms offer an approximation of the optimum within 10-15%, while time consumption remains in the range of a few minutes, even for large-scale scenarios with 10,000s of customers. Beyond topology design, the results provided by these methods areThe work described in this paper was carried out with the support of the BONE-project ("Building the Future Optical Network in Europe"), a Network of Excellence funded by the European Commission through the 7th ICT-Framework Programme, and has been supported by HSNLab, Budapest University of Technology and Economics, http://www.hsnlab.hu.A. Mitcsenkov (B) · G. Paksy · T. Cinkler useful for a preliminary CAPEX estimation and technoeconomic comparison.

Optical access networks provide a future proof platform for a wide range of services, and today, several operators are deploying fibre to the home (FTTH) networks. Installing an FTTH infrastructure, however, involves very high investment cost. Therefore, a good estimation of the investment cost is important for building a successful business strategy and, consequently, to speed up the FTTH penetration. In this paper, for calculating the amount of cable and fibre in the outside plant together with the associated civil works, and the number of required network elements, two different approaches are investigated: (1) geometric modelling of the fibre plant based on approximate mathematical models and (2) geographic modelling of the fibre plant based on map-based geospatial data. The results obtained from these two approaches can then be used as input for preliminary investment cost calculations and/or techno-economic evaluations. Compared to more complex and accurate geographic modelling, we verify that especially with uneven population density and irregular street system, simple geometric models do not provide accurate results. However, if no geospatial data is available or a fast calculation is desired for a first estimation, geometric models definitely have their relevance. Based on the case studies presented in this paper, we propose some important guidelines to improve the accuracy of the geometric models by eliminating their main distortion factors.

A geographic approach is proposed to accurately estimate the cost of FTTH networks. In contrast to the existing geometric models, our model can efficiently avoid inaccurate estimation of the fibre infrastructure cost in the uneven-populated areas.

We propose two algorithms for dynamic routing of guaranteed bandwidth pipes with shared protection that provide low blocking through thrifty resource usage.We assume that a single working path can be protected by one or multiple protection paths, which are partially or fully disjoint from the working path. This allows better capacity re-use (i.e., better capacity sharing among protection paths). Furthermore, the resources of a working path affected by a failure can be re-used by the protection paths.The main feature of the proposed protection rearrangement framework is that since the protection paths do not carry any traffic until a failure they can be adaptively rerouted (rearranged) as the traffic and network conditions change. This steady reoptimisation of protection paths leads to lower usage of resources and therefore higher throughput and lower blocking.The other novelty we propose in this paper is a modelling trick referred to as LD: Link Doubling that allows distinguishing the sharable part of the link capacity from the free capacity in case when multiple protection paths are being rerouted simultaneously. LD allows finding optimal routing of shared protection paths for the case of any single link failure!The obtained results can be used for routing with protection in SDH/SONET, ngSDHUSONET, ATM, MPLS, WR-DWDM (including ASTN/GMPLS) and other networks.

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