Gustavo B. Figueiredo

A minimum interference routing algorithm

Minimum interference routing is instrumental to MPLS traffic engineering under realistic assumptions of unknown traffic demand. This work presents a new algorithm for minimum interference routing, called light minimum interference routing (LMIR). This algorithm introduces a new approach for critical link identification that reduces the computational complexity. Results, derived via simulation, show that LMIR is precise and has indeed a low computational complexity.

A minimum interference routing algorithm with reduced computational complexity

Minimum interference routing algorithms are designed to reduce rejections of future requests for the establishment of Label Switched Paths (LSPs) but make no assumption about specific patterns of arrival request. This paper introduces a novel minimum interference routing algorithm, Light Minimum Interference Routing (LMIR), which is based on a new approach to the identification of critical links. This approach reduces the computational complexity involved in finding a path for the establishment of an LSP. The LMIR is shown to have the same precision as existing algorithms but with less computational complexity.

Channel reusability for burst scheduling in OBS networks

This paper presents a novel channel scheduling policy for optical burst switching networks called least reusable channel (LRC). LRC decides to which interval of the output channel (void) an incoming burst should be allocated on the basis of reuse of the remaining voids. LRC dynamically uses information available to make allocation decisions. It is shown here that LRC produces lower blocking probability and distributes losses more uniformly among routes than do other existing scheduling policies.

On the Transformation of Multifractal Traffic at Ingress Optical Burst Switches

Ingress nodes of Optical Burst Switching (OBS) networks are responsible for assembling burst out of incoming packets and to forward these bursts into the OBS network. The most common criteria for burst assembly are based either on time or on traffic volume. The change of the statistical characteristics of a traffic stream at an ingress switch can affect the quality of service provisioning. Therefore, the statistical characteristics of the output flow of an ingress node need to be known for appropriate network dimensioning and service provisioning. This paper evaluates the impact of burst assembly mechanisms on the scaling properties of multifractal traffic flows. It is showed that the most relevant factor that determines the nature of the output traffic flow is the relationship between the cut-off time scale of the input traffic and the time scale of assembly threshold.

Resilient cloud network mapping with virtualized BBU placement for cloud-RAN

Cloud Radio Access Network (C-RAN) will improve mobile radio coordination and resource efficiency by allowing baseband processing unit (BBU) functions to be virtualized and centralized, i.e., deployed in a BBU hotel. We consider a BBU hoteling scheme based on the concept of access cloud network (ACN). An ACN consists of virtualized BBUs (vBBUs) placed in metro cloud data centers (metro DCs). A vBBU is connected to a set of remote radio heads (RRHs). ACN resiliency against network and processing failures is critical for C-RAN deployments. Hence, in this study, we propose three protection approaches: 1+1 ACN protection, 1+1 ACN and vBBU protection, and partial ACN protection. Simulation results show that both 1+1 ACN and 1+1 ACN and vBBU protection requires large capacity for backup to provide 100% survivability for singlelink and single-DC failures. As a result, we suggest a partial ACN protection approach which provides degraded services with only 8% additional network resources.

On QoS-Assured Degraded Provisioning in Service-Differentiated Multi-Layer Elastic Optical Networks

Degraded provisioning provides an effective solution to flexibly allocate resources in various dimensions to reduce blocking for differentiated demands when network congestion occurs. In this work, we investigate the novel problem of online degraded provisioning in service-differentiated multi-layer networks with optical elasticity. Quality of Service (QoS) is assured by service-holding-time prolongation and immediate access as soon as the service arrives without set-up delay. We decompose the problem into degraded routing and degraded resource allocation stages, and design polynomial-time algorithms with the enhanced multi-layer architecture to exploit network flexibility in temporal and spectral dimensions. Numerical results verify that we can achieve significant blocking reduction, especially for requests with higher priorities. They also indicate that degradation in optical layer can increase the network capacity, while degradation in electric layer provides flexible time-bandwidth exchange.

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.

Optimal algorithms for the batch scheduling problem in OBS networks

This paper introduces optimal batch scheduling algorithms for the problem of scheduling batches of bursts in optical burst switching networks. The problem is modelled as a job scheduling problem with identical machines. The consideration of previously scheduled bursts in the scheduling allows such modeling. Two optimal algorithms with polynomial time complexity are derived and evaluated. Results show that the algorithm that allows re-scheduling of previously scheduled bursts leads to preferred solutions. Moreover, an extended version of the JET reservation protocol is proposed for efficient handling of batches of bursts. Results obtained via simulation prove the superior performance of the BATCHOPT algorithm.

Algorithm with Linear Computational Complexity for Batch Scheduling in OBS Networks

This paper introduces a batch scheduling algorithm for OBS networks which has linear computational complexity. A transformation of the problem formulation is applied to allow the modeling of the problem as a job scheduling with identical machine type of problem. The proposed algorithm was compared to several other heuristic. Results show that it produces a lower bound to the blocking probability of those given by heuristics and it is only 3% slower than the fastest one.

Improving QoS and QoE Through Seamless Handoff in Software-Defined IEEE 802.11 Mesh Networks

To deliver an enhanced mobility experience, wireless networks must provide seamless handoff to mobile clients. Moreover, the handoff process should preserve quality-of-service (QoS) and quality of experience (QoE) at acceptable levels. This letter presents a strategy to provide seamless mobility in wireless mesh networks, considering software-defined network-controlled handoff and passive measurements. To validate the proposal, we deployed a 802.11/OpenFlow test bed and performed extensive experiments. Experimental results demonstrated improvements of QoE up to 70% while keeping key QoS metrics below real-time applications constraints.