Areas of Interest:

I have interest in the general area of Communication systems, Wireless and Wired access and backhaul technologies, Data and Voice communication systems. 

I am particularly interested in design and analysis of protocols and optimization of overall performance of systems related to communication and computer networks.

Academic Background:

• Doctorate in Computer Networking and Telecommunication Networks, (Aug`00 - Dec`04)
  School of Computing and Engineering
  University of Missouri-Kansas City, Kansas City, Missouri.
  Advisor: Prof. Deep Medhi
  Committee: Prof. Appie vande Liefvoort, Prof. Khosrow Sohraby, Prof. Cory Beard, Prof. Xiaojun Shen.
  Title: Models and Algorithms for Effective Traffic Engineering of Tunnel-based Networks (pdf, ps)
  The thesis was adjudged with Honorable Mention at INFORMS Telecommunication Section Ph.D. Dissertation Award for Operations Research in Telecommunications for 2006.
   
• M. E. in Telecommunication, (July`97 - Jan`99)
  Electrical Communication Engineering Department,
  Indian Institute of Science, Bangalore.
  Advisor: Prof. Utpal Mukherji
  Committee: Prof. Anurag Kumar, Prof. Kumar N. Sivarajan
  Title: Performance Analysis of Dynamic Threshold Scheme for High Speed ATM Switches

• B.Tech in Electronics and Communication Engg., (July`93 - June`97)
  College of Technology
  Govind Bhallabh Pant University of Agriculture & Technology, India.
  Advisor: Prof. K. K. Sharma
  Title: Performance Comparison of CDMA systems with FDMA/TDMA Systems
  
  

Professional Experience:

• Network Engineer and Subject Matter Expert, (Apr`06-Apr`08)
  Transport Network Optimization Group
  Schema Inc., New Jersey, USA.
  Abstract: We work towards engineering, design and planning of wireless networks. Towards this end, we have implemented solutions for engineering of RF as well as backhaul network design problems. I have been focusing on optimizing the backhaul (wire line) traffic for wireless carriers. I have been involved in various activities such as product management, research and development, professional services and pre-sales engineering.
  • Towards product management, I have been interacting with clients to identify new and relevant problems, and present to management the long/short term refinements/ upgrades/ modules that would serve to provide future strength to the product. Specific suggestions included availability and survivability requirements, systematic procedures for accurate network baselining and subsequent creation of detailed implementation plans/cutover reports, and architecture and high-level design document for a bare-bone network management system for smaller wireless service providers.
  • I have been involved in the development/implementation of solution procedures in our tool to problems such as Hubbing and SONET/SDH Ring Design. As an optimization expert, I developed and implemented the schedules for incorporation of changes in service providers’ network with minimum cost and zero down-time, developed a systematic procedure for assimilation of multiple network management systems and billing dumps from service providers’ network and isolation of erroneous entries, developed multiple procedures to ensure seamless process for the use of various product modules, individually and in conjunction.
  • In professional services, I have been involved in application of our tools to the client’s networks (Nationwide Wireless Service Providers in USA). Interacted with customer teams as a subject matter expert and worked with them to collect data dump from their network management systems, identified the customer challenges and issues and their expectations from the project. Conducted multiple network design strategies accompanied by scores of “what-if” scenarios based on customer discussions and understanding of their pain-points. Prepared and presented a detailed presentation and report of the various studies and the associated implementation challenges, followed by detailed discussions with engineering teams to arrive at a suitable solution. The solution was not only based on network OpEx but also based on corporate “best practices.” Project would culminate with a concise presentation to higher management outlining the phases/activities, the benefits and the achieved ROI of the project.
  • Pre-sales activities included conducting trials for prospective customers and presenting to their executives, the prospective savings and benefits that the tool brings to them. It also included understanding the customer network, requirements and issues, and then deciding on the modules (one or more) to use, which acted as input to the sales team to refine their pitch. Typically would require explaining to the customer the overall process and the ease with which it can be embedded in the customer’s internal engineering process and activities. To help the customer better appreciate the power of the tool, it would, sometimes also require to explain the inner-workings and the algorithmic level details, albeit, in a simple to understand language.

“Incorporating Practical issues in Design and Planning of Wireless Networks,” tutorial in International Tele-traffic Congress, Ottawa, Canada 2007.

“Recognition of Outstanding Efforts and Achievements,” Individual Performance Award, Schema Inc, 2006.

• Post Doctoral Researcher, (June`05 - March`06)
  Affiliated to INRS-Telecommunication, Montreal, Canada
  GERAD, University of Montreal, Montreal, Canada
  Faculty: Prof. Andre Girard and Prof. Brunilde Sanso
  Title: Performance models for Design and Engineering of IP Transport for WiMAX Backhaul Networks.
  Summary: The focus of the work was to design and engineer backhaul of WiMAX Access Networks with IP transport based on differentiated services architecture. High cost of capacity in the backhaul segment forms the driver for evaluating various approaches for IP capacity planning. We compared various mechanisms in terms of required capacity and in terms of their capability to guarantee the quality of service to individual applications. We considered “absolute” and “average” delay bound requirements. Absolute enforces that each packet has less than the required delay, and average ensures that on an average (over all packets) the delay requirement is enforced. For each one, we evaluated the amount of capacity required for given multimedia applications. We considered specific examples of voice and video and determined the amount of capacity required to guarantee absolute and average delays. Furthermore, we simulated an actual IP link based on DiffServ architecture and present results in terms of encountered delay for the already computed capacities.
  
  
• Consultant, (Dec`04 - May`05)
  RF Engineering Group
  Nortel Networks, Kansas City, Missouri, USA.
  Summary: The group provides performance related support for wireless equipments installed by a nationwide service provider located in Kansas City, MO (Sprint Inc). The group supports field testing and performance guarantees for the installed Base Stations. My project was towards performance estimation of a newly laid down EVDO network in various markets as compared to the older 1xRTT network. The estimates were based on actual field measurements of power, Ec/Io and throughput. The project required using the R-language to derive actual power and throughput measures and identify areas with higher interference, call drop or handoff events.
  
  
• Research Engineer, (Mar`99 - July`00)
  Computer Science R & D Group,
  Sasken Communication Technologies Ltd., Bangalore, India.
  Summary: The group’s vision was to provide product engineering and design expertise to the other software development groups. I was primarily associated with a group developing general packet radio service (GPRS) protocol stack for mobile handsets. Power and memory constrained environment of a mobile handset required appropriate choice of algorithms and fine-tuning of their required parameters to ensure optimum performance of the stack.
  • Drove the requirement and choice of an internal buffer manager to improve the performance of the product based on partially shared hierarchal buffers. My role included altering the design document of the stack to cover the changes required to incorporate the buffer manager.
  • Simulated the complete GPRS hand set and base station while incorporating call models to benchmark the performance of the stack under development. The engine included handset MAC and Link Layer, Base station MAC, link layer, resource allocation and performance management. The simulator was written using Network Simulator (ns-2) and paved way to tune/alter known algorithms towards achieving better performance of the GPRS stack.

Teaching Experience:

• Instructor
  
  • Introduction to Computer Architecture, (Winter 2001)
    UnderGraduate Course (15 students)
    
  • Course: Discrete Structures II, (Fall 2000)
    UnderGraduate Course (45 students)
    
    
• Teaching Assistant
  Graduate courses: Network Architecture II, Network Routing, Network Design & Analysis.
  

Journal Publications/Submissions:

• S. Srivastava, D. Medhi, A. Liefvoort, ``Traffic Engineering of Tunnel-based Networks in the presence of Heterogeneous Streams,'' under submission.
• S. Srivastava, A. Girard, B. Sanso,``Capacity Planning and Design of WiMAX Access Networks,`` in WiMAX Network Planning and Optimization, edited by Y. Zhang, Auerbach Publications, Taylor&Francis Group, USA, 2008

• S. Srivastava, A. Girard, B. Sans`o, ``Design of QoS Aware IP Network Supporting Services with Average Delay Requirement,'' Les Cahiers du GERAD, Report #G–2006–13, Group for Research in Decision Analysis, University de Montreal, Canada, March 2006

• S. Srivastava, D. Medhi, ``Traffic Engineering of Tunnel-based Networks having Class Specific Diversity Requirements,'' in Journal of Combinatorial Optimization, special issue on Communication Networks and Internet Applications, vol. 12, no. 1-2, September 2006.
• S. Srivastava, G. Agarwal, D. Medhi, M. Pioro, "Determining Link Weight Systems under Various Objectives for OSPF Networks using Lagrangian Relaxation-based Approach,'' in IEEE e-Transactions on Network and Service Management (e-TNSM), vol. 2, no. 1, November 2005.
• S. Srivastava, S. R. Thirumalasetty, D. Medhi, "Network Traffic Engineering with varied levels of Protection in Next Generation Internet,'' GERAD 25th Anniversary Issue for Performance Evaluation and Planning Methods for the Next Generation Internet, edited by A. Girard, B. Sanso, F. Vazquez-Abad, Kluwer Publisher, 2005.
• S. Srivastava, B. Krithikaivasan, C. Beard, A. Liefvoort, D. Medhi, W. Alanqar, A. Nagrajan "Traffic Engineering using QoS Routing and Network Controls", Computer Communications, vol 27/5, pp. 387-399, March 2004.

Conference Publications/Submissions:

• S. Srivastava, G. Agrawal, D. Medhi, "Dual-Based Link Weight Determination Towards Single Shortest Path Solutions for OSPF Networks,'' proceedings of International Teletraffic Congress, China, 2005.
• A. Srivastava, S. Srivastava, K. Mitchell, "Determining Traffic and Control Channels for a Packet Based Cellular System having Time-Varying Traffic,'' proceedings of IEEE Vehicular Technology Conference, Spring 2005, Sweden.
• B. Krithikaivasan, S. Srivastava, D. Medhi, M. Pioro, "Backup Path Restoration Design using Path Generation Technique", proceedings of Design of Reliable Communication Networks, Alberta, Canada, 2003.
• S. Srivastava, B. Krithikaivasan, D. Medhi, M. Pioro, "Traffic Engineering in the presence of Tunneling & Diversity Constraints: Formulation and Lagrangean Decomposition Approach", proceedings of International Teletraffic Congress, Berlin, Germany, 2003.
• S. Srivastava, K. Mitchell, A. Vande Liefvoort, " Correlations Induced in a Packet Stream by Background traffic in Multiplexed Environment", proceedings of International Teletraffic Congress, Berlin, Germany, 2003.
• B. Krithikaivasan, S. Srivastava, C. Beard, A. Vande Liefvoort, D. Medhi, "Controlling Performance in the Congested Parts of an Asymmetric Network using Controls and Routing", proceedings of IEEE International Symposium on Computers and Communications, Ankara, Turkey, 2003.
• S. Srivastava, B. Krithikaivasan, C. Beard, A. Liefvoort, D. Medhi, W. Alanqar, A. Nagarajan,    "A Case Study on Evaluating the Benefits of MPLS Traffic Engineering with Constraint-Based Routing and Network Controls", proceedings of Symposium on High Speed Networks, IEEE International Conference on Communications, New York, 2002.
• S. Srivastava, M. N. Umesh, G. Maheedhar, "An Analytical Study on Effects of Retrials on Channel Allocation Schemes", proceedings of Advanced Telecommunication Symposium,  Applied Telecommunications Symposium, Advanced Simulation Technology Conference, Washington DC, 2000.

Submitted/Working Papers:

• "Impact of Number of Servers on Correlation Structure of a Tagged Stream in a Multiplexed Environment,'' Under Preparation.
• "Interference Minimization Approach to Channel Assignment in Cellular Networks,'' Under Preparation.
• "Routing of Heterogeneous Streams in Optical Networks,'' Under Preparation.
• "Diversity based Protection Mechanisms for Shortest Path Networks,'' Under Preparation.
• "Path Generation technique for Robust Design of Wide-Area Communication Networks," Under Preparation.
  

Resume:    

• Research Positions  (pdf, ps)
• Industry Positions   (doc)
  

Last Modified: 1^st May 2008