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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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Subject: search.filters.subject.Routing and wavelength assignment

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    An energy-efficient impairment-aware routing algorithm for optical transport networks
    (IEEE, 2021-03) Molefe, Mlungisi; Nleya, Bakhe; Chidzonga, R.; Bopape, Lebogang; Sibiya, K.
    Flexible Translucent optical Transport networks have the capability to provision multiple data rate demands much more efficiently than the traditional wavelength routed optical backbone networks. By design, in order to suffice the signal reach constraint, traditional optical networks also include several repeaters that are located sparsely along each signal path so as to facilitate successful end-to end transmission of those lightpath connection signals that otherwise would exceed the optical reach. The presence of physical impairments coupled with the inclusion of repeaters that facilitate signal amplification, timing and refreshing means more overall operational power requirements. Thus, energy efficient operation of flexible Translucent Optical Transport Networks is quite crucial. Thus, in this paper we propose a combined physical impairments-aware as well as energy-efficient available network resources allocation algorithm that bases on path availability, considering the impact of energy consumption minimization versus quality of transmission (QoT). We consider the impact of physical impairments in the formulation of the algorithm. We carry out simulation validations of the proposed algorithm which generally indicate to an improvement of energy efficiency as well as other key network resources utilization.
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    A limited intermediate node buffering based RWA scheme in OBS backbone networks
    (Ponte Academic Journal, 2019-11) Nleya, Bakhe; Mutsvangwa, Andrew
    An all optical backbone Optical Burst Switched (OBS) network comprises of a multitude of optical transport sub-systems erected in commercial, residential as well as industrial ar-eas. The heterogeneous nature of the large volumes of traffic gen-erated by various applications and services ideally requires an op-tical backbone network infrastructure to accommodate it. Such a network must be continuously adaptable to the changing nature of the traffic as well as its spontaneous growth with time. In so doing, it has to ensure high end-to-end quality of service (QoS), availabil-ity as well as provision adaptable controllability in cooperation with peripheral (service) layer networks. To successfully design and deploy a cost-effective backbone network, consideration must be taken with regards to system configuration, as well as in applied devices manufacturing. This is to ensure that any component failure does not add any noticeable performance degradation as the network will quickly reconfigure itself accordingly. At operational level, ef-fective routing approaches are necessary to ensure minimized con-gestion as well as contention occurrences. The aggregation of both transit and local traffic at a node influences each other such as to aggravate congestion and to a certain extent reduce contention oc-currences (due to the streamline effect). In this paper, we propose a priority based intermediate Node Buffering based PIB-RWA scheme to combat the problem of contention occurrences and to prevent bursts discarding. It basically selects primary as well as deflection paths/links based on past contention frequency occurrences as well as current resources states in the candidate paths. Furthermore, the scheme also augments intermediate buffering provisioning for con-tending data bursts that are almost reaching the destination. Simu-lation results show that the scheme performs well in terms of key QoS metrics such as network throughput, data burst loss probabil-ities as well as load balancing.