Survivable Impairment-aware Traffic Grooming in WDM Rings

Wavelength Division Multiplexing (WDM) optical networks offer a large amount of bandwidth using multiple, but independent wavelength channels (or lightpaths), each operating at several Gb/s. Since the traffic between users is usually only a fraction of the capacity offered by a wavelength, several independent traffic streams can be groomed...

QoS routing: Average complexity and hopcount in m dimensions

QoS routing is expected to be an essential building block of a future, efficient and scalable QoS-aware network architecture. We present SAMCRA, an exact QoS routing algorithm that guarantees to find a feasible path if such a path exists. The complexity of SAMCRA is analyzed. Because SAMCRA is an exact algorithm, most findings can be applied to...

An overview of constraint-based path selection algorithms for QoS routing

Performance evaluation of constraint-based path selection algorithms

Dynamic Routing in QoS-Traffic Engineered Networks

Inter-domain routing in optical networks wavelength converters

With the increasing deployment of wavelength division multiplexing (WDM) optical networks, the need for advanced lightpath provisioning algorithms and protocols in a multi-domain setting is becoming evident. In order to increase efficiency by relaxing the wavelength continuity constraint in WDM optical networks, wavelength converters are often...

Techniques for measuring quality of experience

Quality of Experience (QoE) relates to how users perceive the quality of an application. To capture such a subjective measure, either by subjective tests or via objective tools, is an art on its own. Given the importance of measuring users’ satisfaction to service providers, research on QoE took flight in recent years. In this paper we present...

Decreasing the spectral radius of a graph by link removals

The decrease of the spectral radius, an important characterizer of network dynamics, by removing links is investigated. The minimization of the spectral radius by removing m links is shown to be an NP-complete problem, which suggests considering heuristic strategies. Several greedy strategies are compared, and several bounds on the decrease of...

Survivable Impairment-Aware Traffic Grooming

Traffic grooming allows efficient utilization of network capacity by aggregating several independent traffic streams into a wavelength. In addition, survivability and impairment-awareness (i.e., taking into account the effect of physical impairments) are two important issues that have gained a lot of research interest in the area of optical...

Gossip-based counting in dynamic networks

We propose Gossipico, a gossip algorithm to average, sum or find minima and maxima over node values in a large, distributed, and dynamic network. Unlike previous work, Gossipico provides a continuous estimate of, for example, the number of nodes, even when the network becomes disconnected. Gossipico converges quickly due to the introduction of a...

Impairment-Aware Routing in Translucent Spectrum-Sliced Elastic Optical Path Networks

Spectrum-sliced elastic optical path (SLICE) technology offers a more flexible bandwidth allocation in optical networks than wavelength division multiplexing. It allows different connections to be served via different modulation formats. However, as with any optical network, the optical signal may be susceptible to signal impairments, especially...

Finding critical regions in a network

It is important that our vital networks (e.g., infrastructures) are robust to more than single-link failures. Failures might for instance affect a part of the network that resides in a certain geographical region. In this paper, considering networks embedded in a two-dimensional plane, we study the problem of finding a critical region - that is,...

Critical regions and region-disjoint paths in a network

Due to the importance of communication networks to society, it is pertinent that these networks can withstand failures. Improving the robustness of a network usually requires installing redundant resources, which is very costly. Network providers are consequently less inclined to take robustness measures against failures that are unlikely to...