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Faculty of Engineering and Built Environment

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Author: search.filters.author.Khumalo, Zephaniah Philani

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    Services and applications security in IoT enabled networks
    (IEEE, 2018-12) Khumalo, Zephaniah Philani; Nleya, Bakhe; Gomba, Ndadzibaya Masimba; Mutsvangwa, Andrew
    5G wireless together with optical backbone networks are expected to be the main pillars of the envisaged next /future generation networking (N/FGN) infrastructures. This is an impetus to practical realization of an IoT network that will support and ensure relatively higher bandwidth as well as enhanced quality of service (QoS) in both access and core network sections. The high-speed wireless links at the network peripherals will serve as a conducive platform for device-to-device (D2D) communication. D2D driven applications and services can only be effective as well as secure assuming the associated machine type communication devices (MTCDs) have been successfully verified and authenticated. Typically, D2D type services and applications involve the interaction of several MTCDs in a group. As such, secure and effective D2D group-based authentication and key agreement (AKA) protocols are necessary. They need to inherently achieve efficacy in maintaining the group key unlink-ability as well as generate minimal signalling overheads that otherwise may lead to network congestion. In this paper we detail a secure and efficient Group AKA (Gr-AKA) protocol for D2D communication. Its performance is compared to that of existing similar protocols and is found to comparably lower both computational as well as signalling overhead requirements. Overall the analysis shows that the Gr-AKA protocol improves performance in terms of fulfilling D2D communication's security requirements.
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    Energy-aware lightpath routing algorithm for optical transport networks
    (TELKOM, 2019-09-01) Gomba, Ndadzibaya Masimba; Nleya, Bakhe; Dewa, Mendon; Mutsvangwa, Andrew; Khumalo, Zephaniah Philani
    Current as well as future applications and services are characterized by bandwidth intensiveness and as such are directly driving the need for the deployment as well as operation of backbone networks that optimize on bandwidth provisioning. Since infrastructural hardware equipment requirements are trebling every two years because of continued surging bandwidth demands, the telecommunication industry is also a growing direct contributor to worldwide greenhouse gases (GHG) emissions as well as energy consumption. This is driving necessities to research on more energy efficient networking approaches. A novel optimized energy-aware lightpath routing (OEA-LR) algorithm is herein proposed. It primarily takes into account the effects of physical layer impairments (PLI) since their effects in high capacity translucent optical networks may not be ignored when formulating routing and wavelength assignment (RWA) algorithms. We assume an all-optical network hence connection requests from source to destination are entirely provisioned in the optical domain, thus optical-electrical-optical (OEO) conversions are not utilised. Both analytical and simulation results indicate that the proposed algorithm improves both energy efficiency operation as well as resource utilization of the network. We further conclude on a general observation of reciprocations between energy savings and blocking performance.
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    A controlled deflection routing and wavelength assignment based scheme in Optical Burst Switched (OBS) networks
    (Walter de Gruyter GmbH, 2020-07-05) Nleya, Bakhe; Khumalo, Zephaniah Philani; Mutsvangwa, Andrew
    Abstract - Heterogeneous IoT-enabled networks generally accommodate both jitter tolerant and intolerant traffic. Optical Burst Switched (OBS) backbone networks handle the resultant volumes of such traffic by transmitting it in huge size chunks called bursts. Because of the lack of or limited buffering capabilities within the core network, burst contentions may frequently occur and thus affect overall supportable quality of service (QoS). Burst contention(s) in the core network is generally characterized by frequent burst losses as well as differential delays especially when traffic levels surge. Burst contention can be resolved in the core network by way of partial buffering using fiber delay lines (FDLs), wavelength conversion using wavelength converters (WCs) or deflection routing. In this paper, we assume that burst contention is resolved by way of deflecting contending bursts to other less congested paths even though this may lead to differential delays incurred by bursts as they traverse the network. This will contribute to undesirable jitter that may ultimately compromise overall QoS. Noting that jitter is mostly caused by deflection routing which itself is a result of poor wavelength and routing assigning, the paper proposes a controlled deflection routing (CDR) and wavelength assignment based scheme that allows the deflection of bursts to alternate paths only after controller buffer preset thresholds are surpassed. In this way, bursts (or burst fragments) intended for a common destination are always most likely to be routed on the same or least cost path end-to-end. We describe the scheme as well as compare its performance to other existing approaches. Overall, both analytical and simulation results show that the proposed scheme does lower both congestion (on deflection routes) as well as jitter, thus also improving throughput as well as avoiding congestion on deflection paths.
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    Data re-sequencing in Smart Grids
    (IEEE, 2016-11) Khumalo, Zephaniah Philani; Nleya, Bahke
    Currently, legacy electrical power grids are being modernized into Smart Grids. These will in turn play a crucial role in real-time balancing between energy productions versus energy consumption. Each Smart Grids will dedicate an advanced metering infrastructure that facilitates collection, storing as well as analyzing data from smart meters to the authorized parties, and also carrying commands, requests, messages and software up­dates from the authorized parties to the smart meters. As such, data aggregation as well as unimpeded data relaying is a prerequisite for guaranteeing a large acceptance and deployment of Smart Grids. In this paper we provide an overview framework for analyzing packet re-sequencing within the Smart Grid. We utilize the random shortest path calculation algorithm to select the desired routes from source to a given destination. It is from among these that ultimately multipath (dual path) routing of the Advanced Metering Infrastructure data is car­ried out, hence resulting in re-sequencing necessities.