• Consistent Optimized and Trustworthy Deployment of SDN

    Consistent Optimized and Trustworthy Deployment of SDN

    Consistent SDN

    Software defined networking (SDN) brought new interesting challenges by externalizing the task of controlling the network to some generic computer software. In particular, the controller software can modify the network routes by introducing new forwarding rules and deleting old ones at a distributed set of switches, a challenge that has received lots of attention in the last six years.

    This research aims at investigating how to on one hand optimize controller placement and on the second hand how to perform consistent rule updates in SDN.



    • Md Tanvir Ishtaique ul Huque, University of New South Wales.
    • Dr. Guillaume Jourjon, Data61-CSIRO.
    • Dr. Vincent Gramoli, University of Sydney.




    • MTI ul Huque, Guillaume Jourjon, Vincent Gramoli, “Garbage Collection of Forwarding Rules in Software Defined Networks”, accepted in IEEE Communication Magazine.
    • MTI ul Huque, Weisheng Si, Guillaume Jourjon, Vincent Gramoli, “Large-Scale Dynamic Controller Placement”, IEEE Transaction on Network and Service Management, vol. 14(2), March 2017
    • MTI ul Huque, Guillaume Jourjon, Vincent Gramoli, Revisiting the controller placement problem, Local Computer Networks (LCN), 2015 IEEE 40th Conference on, pp. 450-453.
  • Blockchain and Network

    Blockchain and Network

    Investigating blockchain through the prism of networks.

  • Per-Core Networking Stack

    Per-Core Networking Stack

    Rethinking network bound applications

    Networking applications use the Berkeley socket model to interface with a networking stack that resides in the operating system kernel. This model requires costly context switching between applications and the kernel, as well as memory copies on both the sending and receiving path. Context switches require the TLB and caches and can severely degrade instructions per cycle (IPC) for tens of thousands of cycles. This model imposes a limitation on performance which becomes even more apparent with the doubling of bandwidth of network bandwidth every 17-18 months, compared with CPU and DRAM performance doubling only every 26-27 months. For example The Memcached application spends over 80% of CPU time in the kernel networking stack, using less than 5% of the available networking bandwidth.

    Applications using this model also suffer from lack of connection locality, as the kernel can process packets on different cores to the application. Multicore scalability is limited due to the lack of connection locality and synchronisation overhead from sharing networking state across multiple cores. To achieve multicore scalability different parallelisation techniques can be utilised such as a run-to-completion model where packets are processed on the same core, or a streaming model where application and network cores are separate and communicate using message passing. The streaming model has the ability to achieve parallelisation within a request, whereas the run-to-completion model attempts to improve temporal locality by processing packets as early as possible.

    This research aims to evaluate the impact of using kernel bypass technologies listed above, to accelerate network bound applications. Some research questions include:

    •   The design of an efficient zero copy interface to replace the Berkeley socket model.
    •   The performance impact of dedicated networking and application cores, versus a run to completion model. What workloads benefit from each design.
    •   The overhead of the current kernel networking stack.


    • Stephen Mallon, University of Sydney
    • Dr. Guillaume Jourjon, Data61-CSIRO
    • Dr. Vincent Gramoli, University of Sydney




    • Stephen Mallon, Vincent Gramoli, and Guillaume Jourjon, “Are Today’s SDN Controller Ready for Primetime?”, IEEE Local Computer Networks 2016. Dubai, UAE.


    The FIRE (Future Internet Research and Experimentation) initiative is an European endeavor that promotes the creation of wide-scale federations of high -performance testbed and experimentation facilities for internet and network-related research. These facilities include wireless and sensor networks, SDNs, high performanelearn-FORGE-FIREce computing, optical networks, mobile networks, and smart cities. With an ongoing budget of around 20 million Euros, a number of projects are funded to sustain the FIRE facilities and conduct largescale internet research through them. Forging Online Education through FIRE (FORGE) is a project bringing together the worlds of online education and FIRE. FORGE aligns FIRE with the ongoing education revolution for mutual benefit. In particular, this project is concerned with specifying development methodologies and best practices for offering FIRE experimentation facilities to learners, related both to communications and IT but also to other science, technology, engineering and mathematics (STEM) disciplines, leading to a strong connection between the learning community and existing FIRE platforms and supporting tools. Moreover, FORGE is producing educational material reinforced with hands-on experimentation, enhanced by multimedia resources. The courses are free available in different formats, such as HTML, epub3 and Apple iBooks. Now it is easy to experiment on a real high-performance testbed from your laptop or tablet from any location in the world.



    1. Olivier Fourmaux, Mohammed Yasin Rahman, Christos Tranoris, Daan Pareit, Jono Vanhie-Van Gerwen, Guillaume Jourjon, Diarmuid Collins, Johann Marquez Barja, FORGE Enabling FIRE Facilities for the e-Learning Community, 19th Internation Conference on Interactive Collabortive Learning, 2016
    2. Guillaume Jourjon, Johann M Marquez-Barja, Thierry Rakotoarivelo, Alexander Mikroyannidis, Kostas Lampropoulos, Spyros Denazis, Christos Tranoris, Daan Pareit, John Domingue, Luiz A DaSilva, Max Ott, FORGE Toolkit: Leveraging Distributed Systems in eLearning Platforms, IEEE Transactions on Emerging Topics in Computing, 2016
    3. Johann M. Marquez-Barja, Guillaume Jourjon, Alexander Mikroyannidis, Christos Tranoris, John Domingue, Luiz DaSilva, FORGE: Enhancing elearning and research in ICT through remote experimentation. EDUCON2014,  IEEE Global Engineering Education Conference, Istanbul, pp. N/A, April, 2014.