Research Interests

My Research Interests

I am a fourth year Ph.D student in the Computer Science Department of Carnegie Mellon University. My advisor is Dr. Peter Steenkiste.
My primary research interest is in computer networking and distributed systems, focussing in the areas of customized and scalable internet service architectures for differentiated network services. This involves issues from several domains including internet service design, programmable networks, resource allocation, resource management, traffic engineering, Quality of Service (QoS), system performance analysis and security.

My interest in networks was developed in my undergraduate years. As my undergraduate project, I enhanced the ns simulator to add ATM support to it. Before coming to CMU, I worked as a teaching and research assistant in the Computer Science department of LUMS where I continued work on my undergrad project and studied the dynamics of the behaviour of TCP/IP over ATM using simulations. This developed my interest in issues relating to providing QoS guarantees for data traffic on the internet.

When I came to CMU, I started work with the Darwin Group. Darwin provides Resource Management for Application-Aware Networks. The goal is to define, implement and evaluate a set of resource management mechanisms to support customizable services for value-added networks. Traditionally, fine-grained, run-time resource management activities are driven by the participating end-points. While this design does have certain advantages, such as simplifying the core of the network, it can not satisfy some new demands from both more sophisticated applications and service providers. To meet these challenges, Darwin introduces the concept of a ``Delegate'' which is a piece of java code that can be injected into the network routers to perform customized tasks for value-added services, such as customized packet dropping for video for getting better performance. The Router Control Interface (RCI) provides a programmable interface (functions) which the customized code can use for monitoring and programming the routers. I enhanced both the data and control plane functionality in Darwin to address multi-ingress SLAs. For multi-ingress SLAs, there is an issue that how the egress bandwidth should be managed. If the ingress node meters have a static share allocation then it will lead to wastage of reserved bandwidth because of traffic fluctuations. Therefore we need to dynamically adjust these shares. Different customers would have different requirements for how this share is dynamically computed and assigned. Since the ingress meters are distributed, it requires coordination among them for computing the shares. I enhanced Darwin by implementing a DiffServ module in the Router Data Plane and extended the RCI to allow Customized Coordinated Dynamic Metering (CCDM) for handling such an SLA. CCDM is able to satisfy the requirements of a variety of customers in an simple, efficient and scalable manner.

Currently, I am working in the CMU Libra Group. Libra aims to provide Scalable Advanced Network services based on Coordinated Active Components. The current move towards value added services has raised several challenges in deploying these services. The biggest hurdle in this is achieving scalability without making the network complex. Another challenge is to provide customizability to enable a wide range of value added services to be deployed dynamically using coordinated active components. Libra attempts to build a set of core networking services so that value added services can be deployed in a simple, scalable and customizable manner.

Teaching Experience

I have been teaching undergraduate courses at Lahore University of Management Sciences (LUMS) as a Teaching Fellow. I also TAed several courses there before I joined the PhD program at CMU. For details of my teaching experience check out my courses link at LUMS.

Publications

Shah, U. and Steenkiste, P., ``Customizable cooperative metering for multi-ingress Service Level Agreements in Differentiated Network Services," accepted in Ninth International Workshop on Quality of Service (IWQoS 2001), Karlsruhe, Germany, June 2001.
Shah, U. and Seshia, S., ``DAM: A Service Architecture for Countering Distributed Denial-of-Service Attacks ," submitted for publication

Course Projects at CMU

``Countering Distributed Denial of Service Attacks'', in 15-712 Advanced Operating Systems and Distributed Systems. Used anomaly detection for detecting DoS attacks and programmable networks for monitoring and dynamically configuring the edge routers to counter the attacks
``Improving MBone overlay topology'', in 15-849 (B) Computer Systems Performance Analysis. Used measurements of the MBone overlay and physical topology to improve the overlay topology for better performance.
``Cooperative BGP to suppress anomalous route propogation'', in 15-849 Advanced Networks. Introduced the concept of ``trust'' among neighbouring BGP routers for suppressing anomalous route propogation.
``Differential and Linear Cryptanalysis in Evaluating AES Candidate Algorithms'', in 15-827 Security and Cryptography. Explained how differential and linear cryptanalysis works and then provided an evaluation of the AES candidates.
``Match-maker'', in 15-829A Mobile Computing Systems & Applications. Developed a prototype context aware matchmaking application for maintenance scenario.