Eugene Kozlovski

QoS Performance of WR-OBS Network Architecture with Request Scheduling

The paper investigates the QoS performance with service differentiation of the wavelength-routed optical burst switched (WR-OBS) network architecture. The request scheduler was analysed as the means of the QoS provisioning and impact of the request scheduling on the QoS performance was investigated in terms of the burst blocking probability and burst end-to-end delays. The WR-OBS QoS performance was also studied as a function of the wavelength requirement. The trade-off between the wavelength over-provisioning and the maximum scheduling delay satisfying the service requirements is reported for both premium and best-effort traffic classes. It is shown that the request scheduling allows to significantly improve the QoS performance and reduce the wavelength requirement in the WR-OBS.

Analysis of burst scheduling for dynamic wavelength assignment in optical burst-switched networks

We discuss the benefits and limitations of the dynamic RWA in a centralised optical burst-switched network architecture. We present systematic comparison between the performance of the dynamic and static RWA in terms of QoS provisioning and bandwidth utilisation. Additionally, we consider a new component in the WROBS architecture, namely the request scheduler. We demonstrate that its application to the dynamic RWA significantly improves the performance of the WROBS.

Provision of end-to-end delay guarantees in wavelength-routed optical burst-switched networks

In Wavelength-Routed Optical Burst-Switched Networks (WR-OBS), lightpaths are dynamically established for the transmission of bursts (aggregation of packets in edge routers) through a bufferless optical core. In this paper, we show how WR-OBS can provide end-to-end delay guarantees, and introduce methods to achieve fairness in the network. The conditions under which WR-OBS bring operational advantages when compared to wavelength-routed optical networks (WRONs) are identified using an example of a real network and taking into account the diameter of the network and the number of wavelengths required.

Link failure restoration in wavelength-routed optical burst switched (WR-OBS) networks

WR-OBS survivability against single link failures is studied. WR-OBS failure-compensating scheduling is proposed and analysed in terms of burst blocking probability, burst scheduling delay increment, wavelength over-provisioning and as a function of network physical connectivity.

Survivability of wavelength-routed optical burst-switched networks with guaranteed IP services

The paper discusses the problem of ensuring QoS performance in wavelength-routed optical burst-switched (WR-OBS) networks under single link failures. The provision of IP services run over high-speed optical backbones should be resilient to faults in the network, hence the importance of a WR-OBS survivability investigation. A failure-compensating scheduling, residing in the WR-OBS control node, is proposed and analysed in terms of burst blocking probability and burst scheduling delay increment. The WR-OBS wavelength over-provisioning for maintaining guaranteed QoS is also studied as a function of network physical connectivity.

Distributed Router Architecture for Packet-Routed Optical Networks

A new proposal for an optical packet-routed network based on a distributed router architecture in a WDM network is described. Buffering, scheduling and wavelength assignment functions are carried out in routers located at the edge of the network. The destination address is encoded by a given wavelength and allows wavelength-routing in optical core routers. This approach avoids processing and additional buffering delays in core routers. A low packet loss rate and a low latency are critical parameters to guarantee QoS for a particular class of packets and must be carefully considered when IP traffic is directly transmitted over a photonic network. This network architecture requires new hardware elements and these are discussed including a low-crosstalk, large port-count free-space grating router.

Impact of customer interactivity on service provisioning costs in multi-service optical networks

Costs associated with provisioning and maintenance of multimedia-rich interactive services via QoS-guaranteed multipoint-to-multipoint connections are analysed as a function of customer group size and session duration. A session sequencing technique, decreasing these costs, is proposed.

A financial decision support framework for the appraisal of renewable energy infrastructures in developing economies

Purpose – The paper aims to report on an integrated techno-economic framework for the performance analysis of energy production based on the renewable energy resources (RERs). Whilst the majority of existing studies have focussed on technical aspects of RER modelling, the proposed framework incorporates financial assessment into the process of appraising the alternatives of hydropower, wind energy and solar energy infrastructures. An approach to the optimal choice of RER deployment for a specific developing region is formulated and applied to Ghana. Design/methodology/approach – A model comprising technical and economic parameters was developed for analysing the investment rankings of different RERs and comparing them to that of conventional energy sources such as the natural gas combined cycle (NGCC) electric plant. The analysis also included the carbon cost and power generation capacity. The total life cycle costing and levelised cost of energy generated from each resource were modelled for three corpor...

Service Management in Advanced Optical Internet

The concepts of bandwidth sharing based on optical burst or packet switching appear to be capable of enabling quality of service (QoS) within the physical layer of advanced high-speed networks. However, it is yet to be investigated how these concepts can be integrated with management of higher layers of the telecom infrastructure, to ensure service level agreements end-to-end across various administrative and technology domains. We discuss issues associated with mapping of service management requirements into the intelligent optical IP layer, and analyse interactions between the management plane and control plane in the process of maintaining a guaranteed service over the wavelength-routed optical burst switched network (WR-OBS).

Functional evaluation of an integrated IP over WDM management solution

The management of heterogeneous and hybrid networks has been always a challenge for network operators. Different frameworks and architectural approaches have been proposed and investigated in the literature. The purpose of this paper is to present the evaluation results of an integrated network management solution for the provisioning and maintenance of IP over WDM end-to-end services with network parameters derived from Service Level Agreements (SLAs). A detailed description of the test-bed environment as well as an integrated scenario for architectural evaluation is also included.