Samira Afzal

h-index10
3papers
666citations

3 Papers

4.9IVJun 24
An Evaluation of ABR Switching for Time-Shifted Clients in MoQ

Abanisenioluwa Orojo, Tanvir Redoy, Samira Afzal et al.

Media over QUIC enables ultra low latency video streaming over QUIC, but its default quality-switching semantics risk introducing playback gaps during periods of network congestion. The in-progress SWITCH specification for MOQ Transport aims to streamline rate adaptation for MoQ. In this work, we characterize the performance of SWITCH-style Adaptive Bitrate (ABR) for both live and time-shifted clients in a Mininet simulated topology. We validate that standard ABR algorithms can be directly applied to time-shifted playback without modification, yielding substantially higher throughput. We demonstrate that a subscriber can experience increased overall throughput after a rebuffering scenario, and we identify focal points for further optimizations of MoQ ABR switching.

8.8CRJul 21, 2021
A low-overhead approach for self-sovereign identity in IoT

Geovane Fedrecheski, Laisa C. P. Costa, Samira Afzal et al.

We present a low-overhead mechanism for self-sovereign identification and communication of IoT agents in constrained networks. Our main contribution is to enable native use of Decentralized Identifiers (DIDs) and DID-based secure communication on constrained networks, whereas previous works either did not consider the issue or relied on proxy-based architectures. We propose a new extension to DIDs along with a more concise serialization method for DID metadata. Moreover, in order to reduce the security overhead over transmitted messages, we adopted a binary message envelope. We implemented these proposals within the context of Swarm Computing, an approach for decentralized IoT. Results showed that our proposal reduces the size of identity metadata in almost four times and security overhead up to five times. We observed that both techniques are required to enable operation on constrained networks.

3.3NIJun 14, 2019
A Holistic Survey of Wireless Multipath Video Streaming

Samira Afzal, Vanessa Testoni, Christian Esteve Rothenberg et al.

Most of today's mobile devices are equipped with multiple network interfaces and one of the main bandwidth-hungry applications that would benefit from multipath communications is wireless video streaming. However, most of the current transport protocols do not match the requirements of video streaming applications or are not designed to address relevant issues, such as delay constraints, networks heterogeneity, and head-of-line blocking issues. This survey provides a holistic literature review of multipath wireless video streaming, shedding light on the different alternatives from an end-to-end layered stack perspective, unveiling trade-offs of each approach, and presenting a suitable taxonomy to classify the state-of-the-art. Finally, we discuss open issues and avenues for future work.