Browsing by Author "Karamollahi, Mehdi"

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    Pandemic Effects on Campus Network Traffic
    (2023-03-27) Karamollahi, Mehdi; Williamson, Carey; Arlitt, Martin; Krishnamurthy, Diwakar; Willett, Wesley; Haque, Israat; Claypool, Mark; Reardon, Joel
    The first wave of the COVID-19 pandemic hit North America in March 2020, disrupting personal and professional lives, and leading to work-from-home mandates in many jurisdictions. The lockdown measures started at the University of Calgary on March 13, 2020, and the university switched to fully remote learning and working. Although the lockdown measures evolved over the following months, the pandemic significantly affected how people used the campus network in both the short term and the longer term. In this dissertation, we use three years (i.e., 2019, 2020, and 2021) of empirical network traffic measurement data from the University of Calgary’s campus network to study the effects of the pandemic on our post-secondary education environment. The highlights from overall changes on our campus include: changes to inbound and outbound traffic volumes; reduced traffic asymmetry; significant growth in videoconferencing traffic; structural changes in workday traffic patterns; and more global distribution of campus network users. The research in this dissertation takes an applied approach, focusing on the performance implications of these pandemic-related traffic changes as viewed through the lens of a campus edge network. We first study videoconferencing applications and remote access services used during the lockdown. We study their traffic volumes, directionality, and diurnal patterns and characterize them as observed from our campus edge network. Next, we investigate the increase in inbound scanning activities on our campus network during the lockdown. We characterize this traffic, identify the legitimate and suspicious actors involved, and discuss three specific examples of security-related incidents observed on our campus network. The methodology used in these case studies could be used for similar studies. We also study our campus community and analyze the pandemic effects on different sub-communities. Our findings show that the network usage patterns are highly correlated with the physical presence requirements on campus. Moreover, many asymmetries in connection counts and traffic byte volumes are evident, as the pandemic led to many shifts in application usage. Lastly, we select Zoom as the most prevalent videoconferencing application adopted by our campus community and further analyze its network traffic. We investigate connection-level and packet-level Zoom traffic, identify its structure, and identify the root cause of performance problems with Zoom sessions on our campus network. To mitigate these problems, we propose multiple solutions and evaluate them quantitatively using workload modelling and simulation.