Application opportunities associated with video, voice, and data triple-play result in a dramatic demand increase in metro transport networks, with traffic patterns becoming increasingly dynamic and difficult to predict. This is driving the need of core networks with a high degree of flexibility and multigranularities to carry traffic. We propose to investigate the question of what this means in terms of dynamic protection provisioning. In other words, we want to study how stable are the protection structures under dynamic traffic, i.e., how much and how often they need to be updated in a dynamic survivable WDM network. While most studies on the stability of protection structures have been conducted onp-cycles and link shared protection, we propose to investigate here the stability of failure-independent path-protecting (FIPP)p-cycles under dynamic traffic. For doing so, we design and develop an original scalable mathematical model that we solve using large-scale optimization tools. Numerical results show that FIPPp-cycles are remarkably stable under the evaluation of the number of required optical bypass reconfigurations under dynamic traffic.

Traffic grooming consists of packing low rate streams onto a high speed lightpath in order to effectively use the network resources. Under dynamic traffic, rerouting of ongoing connections has been envisioned as a means, to be used very wisely, to reduce the connection blocking rate and to optimize the network resources. In a context of traffic with QoS constraints, only the delay tolerant ongoing connections are rerouted. In this paper, we design three new heuristics, one relying on a mathematical ILP (Integer Linear Program) model and two low complexity ones to carefully reroute ongoing connection requests in order to accommodate the new incoming connection requests, while minimizing connection disturbance. While the ILP model allows the full exploration of a limit on the overall number of reroutings, both heuristics are designed as low complexity heuristics in order to limit the number of rerouting per establishment of a new incoming connection request. Comparative computational results show that the two low complexity heuristics provide much better results in terms of the best compromise between maximizing the throughput and minimizing the number of disturbances of the already established connection requests.

p-Cycles offer a protection that corresponds to an efficient pre-configured and pre-cross-connected protection scheme. Thereafter, we study the stability and the efficient reconfiguration of p-cycles in the context of dynamic asymmetric traffic. The literature acknowledges it as a difficult problem, but which is of paramount importance in the selection of p-cycles as a protection scheme in Intelligent Optical Networks (IONs). We investigate two p-cycle updating models which differ mainly by their objective criteria. The first objective is the classical one, aiming at minimizing the spare capacity. The second one is new and corresponds to the number of pre-cross-connections that needs to be set/reset after each traffic variation, while attempting to maximize the re-use of previously established pre-cross-connection settings in spite of the modifications of the p-cycles. Note that the second model needs to explicitly include wavelength continuity constraints and is therefore slightly more complex. Results show that: (i) The proposed ILP tools are scalable, and (ii) While p-cycles appear not to be very stable with the first criterion, they emerge as highly stable with the second criterion.