Juliana de Santi

Load Balancing for Holding-Time-Aware Dynamic Traffic Grooming

In this paper, a new algorithm for dynamic traffic grooming is introduced. It considers the holding-time of the connections and it aims at balancing the load among existing lightpaths to avoid the formation of bottlenecks and, consequently, high blocking probability values. Results indicate that it produces significantly lower blocking probabilities when compared to other holding-time-aware algorithm. Moreover, it promotes a fair distribution of blocking among source-destination pairs.

Design of optimal Active Queue Management controllers for HSTCP in large bandwidth-delay product networks

Several variants of the Transmission Control Protocol (TCP) have been proposed for overcoming the inefficiency of the TCP Reno when operating in high-speed networks. However, these variants by themselves cannot prevent network congestion. Congestion avoidance also relies on other mechanisms, such as Active Queue Management (AQM). This paper introduces a novel optimal AQM policy to operate in networks that adopt the High Speed TCP (HSTCP) variant as their transport protocol. The effectiveness of various optimal controllers is evaluated and the performance of the new policy is compared to that of Random Early Detection (RED) policy. Results, derived via simulation, reveal the advantages of adopting HSTCP-H2 in large bandwidth-delay product networks.

Leveraging multipath routing and traffic grooming for an efficient load balancing in optical networks

Optical networks can benefit from multipath routing by routing traffic over diverse fiber links to fulfill bandwidth requirements, balance network load and improve resource utilization. This paper focuses on the effectiveness of multipath routing on aggregating residual bandwidth of the established lightpaths using dynamic traffic grooming. An optimization model based on Integer Linear Programing (ILP) is formulated to leverage multipath routing and grooming to serve connection requests with known duration, in a scenario where the dynamic traffic can demand bandwidth either larger or smaller than a single wavelength capacity. The impact of a balancing policy, referred to as Holding Time Balancing (HTBalancing), on multipath routing with traffic grooming in optical networks is also investigated. Numerical results show that the proposed optimization model can achieve a lower bandwidth blocking and a better load balancing with HTBalancing policy, when compared with single path routing. The proposed relaxation algorithm can effectively find near optimal solutions, and be applied in realistic scenarios.

Holding-time-aware dynamic traffic grooming algorithms based on multipath routing for WDM optical networks

This paper investigates approaches for the traffic grooming problem that consider connection holding-times and bandwidth availability. Moreover, solutions can indicate the splitting of connections into two or more sub-streams by multipath routing and fine-tuned by traffic grooming to utilize network resources better. Algorithms are proposed and the results of simulations using a variety of realistic scenarios indicate that the proposed algorithms significantly reduce the blocking of connection requests yet promote a fair distribution of the network resources in relation to the state-of-the-art solutions.

Algorithm for traffic grooming of batches of deadline-driven requests

This paper introduces a novel traffic grooming algorithm for the connection establishment of deadline-driven requests. The algorithm grooms batches of requests rather than individual requests. Results indicate that the algorithm is able to significantly reduce the blocking ratio and promote a fair distribution of blocking among source destination pairs of nodes.

Dynamic energy-aware multipath grooming

This paper investigates the use of multipath grooming to save energy in Wavelength Division Multiplexing (WDM) networks by splitting the bandwidth demand of requests among several paths and aggregating them with already established lightpaths. For that, two algorithms are proposed which employ an auxiliary graph which edge weights represent the energy consumed by all the operations related to the optical transmission in a lightpath to provide the bandwidth requested. Both algorithms select a subset of different sets of k lightpaths in which residual bandwidth surpasses minimally the demanded bandwidth with minimum energy consumption. These two algorithms represent the choice of criteria between energy consumption only or both energy and bandwidth. It is shown that the algorithm which considers both energy and bandwidth employs a lower number of lightpaths while reducing the energy consumption and blocking rate.

Energy-aware de-allocation of lightpaths in WDM networks

This paper proposes a heuristic to de-allocate light-paths in Wavelength Division Multiplexing (WDM) networks for reducing the network energy consumption. The idea is to avoid the overhead involved in the establishment of future lightpaths by rerouting connections to a lightpath to be de-allocated. Numerical results show that the proposed strategy saves energy while maintains blocking ratio at levels compatible to those of algorithms which do not employ rerouting of connections.