The availability requirements for today's networks are very high. Higher availability often comes with a higher cost. We describe several steps required for estimating the costs of realistic network scenarios. Capital expenditures (CapEx) and operational expenditures (OpEx) are classified. An activity-based approach is used to quantify the cost of the event-driven operational processes such as repair and service provisioning. We discuss activity duration and availability parameters as required input data, which are necessary for calculating the processes' costs for realistic network scenarios. The relevant availability measures for an IP-over-Optical network are described using a triplet representation with optimistic, nominal, and conservative values. The model is applied to a reference German network scenario.

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In this paper, a new shared protection mechanism for meshed optical networks is presented. Significant network design cost reductions can be achieved in comparison to the well-known 1+1 protection scheme. Demand-wise Shared Protection (DSP) bases on the diversification of demand routings and exploits the network connectivity to restrict the number of backup lightpaths needed to provide the desired level of protection. Computational experiments approve the benefits of the concept DSP for cost efficient optical network designs.

In recent years, significant work has been completed on traffic engineering enhancements to the generalized multiprotocol label switching protocol suite [1][2][3]. As a next step, reproducing the current trend of switching layers' integration happening in the data plane, network control is foreseen to go beyond the traditional per layer approach and tend toward an integrated model [4,5]. In these multilayer environments, a single GMPLS control plane drives various distinct switching layers at the same time and as a coherent whole, taking benefit from the "common" property of GMPLS. Beyond this application of supporting network control across different technologies, in this article we catalog the unified traffic engineering paradigms, discuss their applicability, and present their enforcement techniques. Furthermore, we show that the common GMPLS concept has the advantage of low operational complexity, and enables unified TE capabilities such as efficient network resource usage and rapid service provisioning.

We assume Intelligent Optical Networks (ION) to be the next step on the transport network evolution path. ION is an acronym for an optical network provided with a control plane (distributed routing and signaling functions for dynamic connection configurations), such as GMPLS and ASON. IONs enable fast service provisioning and make efficient use of network capacity by dynamically allocating resources to services on demand. Furthermore, the distributed control functions allow flexible and cost eMicient resilience schemes in IONs. In the recent past, we have observed increasingly dynamic traffic and service conditions leading to frequent transport network recofligurations. In this paper, we compare the performance of different resilience mechanisms, namely dedicated path protection, shared path protection, shared link protection, pcycles, and restoration, protecting dynamic services.