In this paper, we use Wireshark packet-level traces to study the performance of the Zoom network application. Our work is motivated by several anecdotal reports of Zoom performance problems on our campus network during the Fall 2021 semester. Through the collection and analysis of Wireshark traces from different vantage points, we are able to pinpoint the root cause of the Zoom performance problems, which is a congested external Internet link for our campus network. We also identify several characteristics of the Zoom application that exacerbate its performance issues on congested and lossy networks, due to multi-layer protocol interactions.

In this paper, we develop a synthetic workload model for the Zoom network application based on empirical Zoom traffic measurements on a campus network. We then use this model in a simulation study of Zoom network traffic at the campus scale. The simulation results show that hybrid learning places a substantial load on the campus network, especially on the wireless network. Additional simulation experiments investigate the potential benefits of locally-hosted Zoom infrastructure, improved load balancing strategies for Zoom servers, and multicast delivery models for Zoom network traffic. The results show that the multicast approach offers the greatest potential benefit.

Over the past decade, Instant Messaging (IM) apps have become an extremely popular tool for billions of people to communicate online. In this paper, we use a combination of active and passive measurement techniques to study one week of IM app traffic on a large campus edge network. Despite the challenges of end-to-end encryption, user privacy, NAT, DHCP, and high traffic volumes, we identify the key characteristics of four popular IM apps: Facebook Messenger, Google Hangouts, Snapchat, and WeChat. The main observations from our study indicate a rich ecosystem of IM apps, many of which exhibit strong diurnal patterns, complex user interactions, and heavy-tailed distributions for connection durations and transfer sizes. Collectively, these four IM apps contribute about 650 GB of daily traffic volume on our campus network.

The email delivery ecosystem in modern enterprise networks is large and complex, featuring several email access protocols (e.g., POP, IMAP, HTTP, and the secure versions of each of these). In this paper, we provide a detailed characterization of IMAPS email traffic on a large campus edge network. The main highlights from our study are: (1) commercial cloud-based email services account for most of the campus email traffic; (2) all email access protocols exhibit heavy-tailed transfer size distributions; and (3) the throughputs achieved by large transfers vary widely based on protocol, transfer size, and time of day.