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6 The signaling and control network (SCN) connects network elements (NE) and their associated network element controllers (NEC), cross-layer resource allocator (CRA) and network management system (NMS).
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Introduction The last decade has seen some dramatic changes in the demands placed on core networks. Data has permanently replaced voice as the dominant traffic unit. The growth of applications like file sharing and storage area networking took many by surprise. Video distribution, a relatively old application, is now being delivered via packet tech...
Citations
The management of multilayer networks is often a complex task, since each layer is typically independently operated and maintained, and there is a lack of shared network resource knowledge between layers. In this work, we have illustrated that Ant Colony Optimization (ACO) algorithms can be a suitable solution for coordinated management of disjoint IP and optical layers with limited or no visibility between the control planes of each layer. ACO algorithms are used to achieve fully-distributed multilayer routing policies in IP-over-optical networks. Simulations have demonstrated that ACO-based policies can achieve lower levels of blocking probability and higher levels of restorability for IP connections compared to fixed-alternate routing policies in almost all cases. This better performance is achieved with only small increases in the connection setup and restoration times, and without requiring a significant amount of communication overhead.
Rapidly increasing network demand based on unpredictable services has driven research into methods to provide intelligent provisioning, efficient restoration and recovery from failures, and effective management schemes that reduce the amount of “hands-on” activity to plan and run the network. Integrating the service-oriented IP layer together with the efficient transport capabilities of the optical layer is a cornerstone of this research. Converged IP-optical networks are being demonstrated in large multi-carrier and multi-vendor venues. Research is continuing on making this convergence more efficient, flexible, and scalable. In this chapter, we review the current key technologies that contribute to the convergence of IP and optical networks, describing control and management plane technologies, techniques and standards in some detail. We also illustrate current research challenges, and discuss future directions for research.
Transport optical networks today are typically quasi-static, with connections often remaining established for months or years. As an initial transition from this relatively fixed environment, transport optical networks are becoming configurable. The next step in this evolution is dynamic networking, where connections can be rapidly established and torn down without the involvement of operations personnel. After examining the motivation for dynamic optical networking, the remainder of the chapter presents implementation details. This includes an in-depth look at centralized versus distributed control-plane architectures. The challenges of dynamic networking in the presence of optical bypass or in a multi-domain environment are covered as well. In order for networks to be reconfigured remotely through software, the required equipment must already be deployed in the network. Techniques for estimating the amount of equipment to deploy at a node are presented. As a glimpse into possible future directions of optical networking, the implications of Software-Defined Networking relative to a dynamic optical layer are discussed.
