Jacek Rzasa

Grade-of-service-based routing in optical networks [Quality-of-Service-Based Routing Algorithms for Heterogeneous Networks]

Optical networks serve an increasing number of services, each having different requirements. This necessitates the evolution towards routing algorithms that cover all aspects of quality. This article presents a tutorial overview and comparison of grade-of-service-based routing strategies, with emphasis on mechanisms that provide differentiated call-blocking probability for different classes of lightpath requests

Route Management Strategies for Grade of Service Differentiation in Optical Networks

In the paper we propose three route management strategies that allow an optical network operator to achieve differentiated service for two classes of lightpath requests. Simulation results show that all three strategies achieve the stated goal, which is to maintain blocking probability of high priority requests below an assumed value in a broad range of network loads. Moreover, the presented strategies require only little support from the control plane. Detailed algorithms are presented in two versions, one suitable for networks with centralized control, and the other for networks with distributed control.

Energy-aware fog and cloud interplay supported by wide area software defined networking

The paper focuses on dynamic resource provisioning in an all optical wide area Software Defined Network supporting energy-aware interplay between fog and cloud. The main contribution of this paper is a latencyAware policy for handling fog related traffic. The policy is combined with anycast strategies in order to form a complete approach able to handle fog and cloud traffic simultaneously. The proposed approach was compared with reference solutions with respect to latency of fog related requests, CO2 emission and impact on network performance. It is shown that both latency and carbon footprint may be reduced without significant deterioration of network performance.

Anycast routing for carbon footprint reduction in WDM hybrid power networks with data centers

The paper focuses on dynamic resource provisioning which minimizes carbon footprint in optical networks. The main contribution of this paper consists of three anycast routing strategies aimed at reducing greenhouse gases emission by processing energy-intensive requests in data centers powered from renewable energy sources. The proposed strategies were compared with reference approaches with respect to CO2 emission and their impact on network performance. It is shown that they are able to significantly reduce greenhouse gases emission and, simultaneously, improve network performance.

Performance Evaluation of the Grade-of-Service-Based Routing Strategies for Optical Networks

The paper is focused on an optical network in which the network operator needs to achieve differentiated connection blocking probability between different classes of lightpath requests. We propose and investigate several routing strategies, which may be used for that purpose, i.e., to maintain the blocking probability of the high priority requests below an assumed value in a broad range of network loads. Simulation results show that all proposed strategies achieve the stated goal, but their performance varies considerably. The paper presents differences in performance of individual strategies.

Green Cloud Provisioning Throughout Cooperation of a WDM Wide Area Network and a Hybrid Power IT Infrastructure

The paper focuses on cooperation between cloud and network operators, as well as on fitting particular routing strategies to various cloud services. Three cooperation models are presented, analyzed and compared in the paper: the proposed model and two widely used reference models. The main difference between the models is the set of information being exchanged between the involved parties. Additionally, we analyze the applicability of four fitting schemas for each considered model. It is shown that the proposed model, alongside with an appropriate fitting schema, is able to reduce the blocking probability of cloud services requests. At the same time, thanks to the use of green anycast strategies, it is able to significantly reduce carbon dioxide emission.

Fitting green anycast strategies to cloud services in WDM hybrid power networks

The paper focuses on dynamic resource provisioning which minimizes carbon footprint of data centers interconnected via optical networks. The main contribution of this paper is a schema of fitting energy aware anycast strategies to different types of cloud services in order to reduce greenhouse gases emission. The proposed schema was compared to the cases when all types of cloud services were handled using the same anycast strategy. It is shown that the proposed schema is able to significantly reduce greenhouse gases emission without significant deterioration of network performance.

Dynamic power capping for multilayer hybrid power networks

The paper deals with the problem of optimizing the use of energy in a telecommunication network. We propose the power capping technology to effectively move power hungry tasks from nodes powered from non-renewable energy sources to nodes powered from renewable resources. The presented technology may also be used to optimize OPEX in case the cost of energy varies in different nodes. The presented results show, that the solution is extremely effective in meeting the aforementioned goals.

Resource provisioning for multigranular traffic flows in multilayer networks

The paper deals with the problem of multilayer resource provisioning in a network in which an operator needs to route traffic flows with different data rates. It is shown that the blocking probability of high data rate requests is usually higher than the blocking probability of other requests. A relevant strategy aimed at solving this problem is proposed, investigated, and compared with the known solution. Numerical results confirm that the proposed strategy is able to substantially reduce the blocking probability of high data rate requests at the cost of increased utilization of the packet switching layer and more complex routing of lightpaths.

On stability of virtual topologies in dynamic multilayer networks

The paper addresses the problem of unwanted stabilization of a virtual topology in a dynamic multilayer network using the Packet-Packet-Lambda (PPL) routing strategy. The PPL strategy was already proposed in several papers and is perceived as a valuable solution to the multilayer traffic routing problem in a network with lightpaths created on demand. However, as it is shown, usage of the strategy may bring catastrophic results, since this strategy may create in some point of time an inefficient, extremely stable and long lasting logical topology, which results in a highly penalized network performance. Therefore, enhancements to the strategy are necessary. We show some directions for such improvements.