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Stanford University Networking Seminar

Ihsan Ayyub Qazi (LUMS)
Towards Efficient Networked Systems

2:30pm, Wednesday, December 09 2015
Gates 104

About the Talk

In this talk, I will discuss two projects that my research group has recently worked on.

In the first half of my talk, I will describe PASE, a transport framework for achieving low latency in large-scale cloud applications (e.g., web search and social networking). PASE employs a novel distributed control plane for arbitration between flows, uses priority queues available in existing switches for prioritization at per-packet timescales, and employs TCP-style endpoint-based probing to achieve work conservation. PASE is deployment friendly as it does not require any changes to the network fabric; yet, its performance is comparable to, or better than, the state-of-the-art protocols that require changes in switches (e.g., pFabric). Our results show that PASE performs well for a wide range of application workloads and network settings (This work appeared in ACM SIGCOMM 2014).

In the second half, I will describe C-Saw, a platform for measuring Internet censorship. Collecting continuous and reliable censorship measurements has been a challenging problem due to lack of access to diverse vantage points and lack of incentives for user participation. We show that this problem can be addressed if the measurement platform also provides high performance circumvention. The circumvention capability of C-Saw incentivizes consumers to opt-in. As more and more consumers crowdsource, the monitoring data gets richer. This, in turn, offers greater insights into the censorship mechanisms over a wider region, offering even better circumvention capabilities. Our initial measurement study shows that fine-grained knowledge about the filtering mechanisms used by ISPs can lead to significant improvement in end user performance for accessing censored URLs (This work appeared in ACM HotNets 2015).

About the Speaker

Ihsan Ayyub Qazi is an Assistant Professor of Computer Science in the SBA School of Science and Engineering at LUMS, Lahore, Pakistan. He received his Ph.D. in Computer Science from the University of Pittsburgh, PA USA in 2010 and his BSc. (Hons) degree from LUMS with a double major in Computer Science and Mathematics in 2005. Previously, he has held positions at BBN Technologies and the Centre for Advanced Internet Architectures. His research interests are in computer networks and distributed systems and span cloud computing and datacenters, wireless networks, and Internet censorship. His research has appeared in venues such as ACM SIGCOMM and IEEE/ACM Transactions on Networking. More information can be found at