IBM Watson Research Center
1101 Kitchawan Road
Yorktown Heights, NY, 10598
Phone: 914-945-2062 (Office -- I do not check voicemail)
I was a Ph.D. candidate in the Computer Science Department at Columbia University. I received my Ph.D. degree in February 2011. My advisor was Prof. Henning Schulzrinne. I received M.S. in Computer Science from Columbia in May 2004, and B.S. in Computer System Engineering from GIK Institute of Engineering Sciences and Technology, Pakistan.

I now work at IBM T. J. Watson Research Center. Here is a link to my IBM page.



My research at IBM Watson Lab is focused on cloud computing, particularly, oversubscription, patch management, SLAs, software defined networking, and OpenStack. I am a co-author of SPEC OSGcloud benchmark framework report, and am currently working on the standardization of cloud benchmark.

My PhD work was focused on the reliability, session quality, protocol design and standardization, measurement, and energy efficiency issues in peer-to-peer communication systems. I had proposed an analytical model for understanding reliability in these systems. The model allows system designers to compare the reliability of client-server VoIP systems like Vonage to p2p systems like Skype. I had built OpenVoIP, an open source, open protocol, peer-to-peer communication system and scaled it to 1,000 nodes on ~500 Planet Lab machines. Motivated by the use of TCP in Skype for traversing firewalls, I studied TCP's delay performance for real-time applications such as VoIP and live video streaming. I was the first to analyze the workings of the Skype protocol. I am also active in the IETF's P2PSIP working group and working on the standardization of a peer-to-peer protocol. I also explored the energy efficiency issues in IP-based communication systems.

I am also interested in performance issues in multicore servers and am intrigued by the tradeoffs and dependencies between reliability, performance, and energy tradeoffs in data centers.



Conference and Workshop Papers


Internet drafts




  • Scalable Cluster Router
    Gianluca Iannaccone, Sylvia Ratnasamy, Maziar Manesh, Katerina Argyraki, Byung-Gon Chun, Kevin Fall, Allan Knies, Norbert Egi, Mihai Dobrescu, Salman Baset
    Application number: US 2011/0016223 A1, Filed: Jul 19, 2010.




[2012] Guest Lectures in Cloud Computing Course on OpenStack, and Oversubscription
[2008] Networking Laboratory


[2005] Content Networking (Spring), Anonymity and Privacy (Spring),
[2004] Data Structures and Algorithms in JAVA (3137) (Spring), Computability (Fall)
[2003] Computer Networks (Fall), Data Structures in Java (Fall), Operating Systems (Summer)


  • OpenVoIP
  • Packet and byte-based drop-tail queues in NISTnet
  • CBR and VBR traffic generator


  • Young Scholar Representative on Marconi Society Board, 2011 - to-date.
  • Best paper award at IPTCOMM, August 2010
  • Marconi Young Scholar, Marconi Society, September 2008
  • Service award, Department of Computer Science, Columbia University, 2006
  • Travel Awards: SIGCOMM 2006 and ICNP 2005
  • MS-TA, Department of Computer Science, Columbia University, 2003-2004
  • Won All Pakistan Computer Science Quiz Competition, NUST, Rawalpindi, 2001


  • IBM Watson Distributed & Fault Tolerant Community (DFTC) Professional Interest Community (PIC) chair, 2012 -
  • Release Manager, SPEC OSG cloud subcommittee, April 2012 - to-date
  • Reviewer Journals: ACM Computer Communication Review (CCR), IEEE Transactions on Parallel and Distributed Systems, Elsevier Computer Communications, Journal of Communications, IEEE Multimedia, IBM Journal of Research & Development, Wiley Security & Communication Networks
  • Reviewer Conferences: IEEE Cloud 2012, IEEE Infocom 2010, IEEE Globecom, IMSAA, Networking, IEEE P2P 2008, IPTCOMM, ACM Multimedia
  • Web master ICNP 2009