Jennifer Gossels will be presenting her Generals on May 14, 2015 at 2pm in CS 402. The members of her committee are Jennifer Rexford (adviser), David Walker, and JP Singh. Everyone is invited to attend her talk, and those faculty wishing to remain for the oral exam following are welcome to do so. Her abstract and reading list follow below. Topology Virtualization in Software Defined Networks Software defined networking (SDN) is a promising tool that we can use to improve network performance and simplify network management. SDN is based on the concepts of (1) separation of the data and control planes through an open interface to switch hardware; and (2) logically centralized control. Nevertheless, SDN by itself is not a panacea; we need higher-level abstractions and support for modularity on top of OpenFlow, the industry standard interface between switches and controller. Our work achieves these goals by abstracting a single physical switch into a multi-switch virtual network. With this one-physical-to-many-virtual topology virtualization, administrators can run a combination of off-the-shelf controller applications, each of which relies on its own assumptions about the physical network. In contrast, without virtualization the administrator would need to implement his entire high-level policy in a custom, monolithic application tailored to his physical infrastructure. Further, topology virtualization enhances security by hiding the details of the physical network from third-party applications. In this talk we discuss the challenges of supporting the one-physical-to-many-virtual topology abstraction in SDNs, and then we describe our solutions to these problems. We begin with a precise definition of what it means to correctly implement this abstraction. Then, we present algorithms for translating controller-to-switch messages and switch-to-controller events both correctly and efficiently. We also discuss our implementation of some of these algorithms in our prototype network hypervisor and evaluate their overhead. This work builds on earlier research with Xin Jin, Jennifer Rexford, and David Walker presented at NSDI 2015 [6]. [1] Casado, M., Freedman, M. J., Pettit, J., Luo, J., McKeown, N., and Shenker, S. Ethane: Taking Control of the Enterprise. In Proceedings of the 2007 Conference on Applications, Technologies, Architectures, and Protocols for Computer Communications (New York, NY, USA, 2007), SIGCOMM ’07, ACM. [2] Clark, D. The Design Philosophy of the DARPA Internet Protocols. SIGCOMM Computer Communication Review 18, 4 (August 1988). [3] Ghorbani, S., and Godfrey, B. Towards Correct Network Virtualization. In Proceedings of the Third Workshop on Hot Topics in Software Defined Networking (New York, NY, USA, 2014), HotSDN ’14, ACM. [4] Ghorbani, S., Schlesinger, C., Monaco, M., Keller, E., Caesar, M., Rexford, J., and Walker, D. Transparent, Live Migration of a Software-Defined Network. In Proceedings of the ACM Symposium on Cloud Computing (New York, NY, USA, 2014), SOCC ’14, ACM. [5] Gupta, A., Vanbever, L., Shahbaz, M., Donovan, S. P., Schlinker, B., Feamster, N., Rexford, J., Shenker, S., Clark, R. J., and Katz-Bassett, E. SDX: A Software Defined Internet Exchange. In ACM SIGCOMM 2014 Conference, SIGCOMM ’14, Chicago, IL, USA, August 17-22, 2014 (2014). [6] Jin, X., Gossels, J., Rexford, J., and Walker, D. CoVisor: A Compositional Hypervisor for Software-Defined Networks. In Proceedings of the 12th USENIX Conference on Networked Systems Design and Implementation (May 2015), NSDI ’15. [7] Katta, N., Alipourfard, O., Rexford, J., and Walker, D. Infinite CacheFlow in Software-Defined Networks. In Proceedings of the Third Workshop on Hot Topics in Software Defined Networking (New York, NY, USA, 2014), HotSDN ’14, ACM. [8] Kazemian, P., Chang, M., Zeng, H., Varghese, G., McKeown, N., and Whyte, S. Real Time Network Policy Checking Using Header Space Analysis. In Proceedings of the 10th USENIX Conference on Networked Systems Design and Implementation (Berkeley, CA, USA, 2013), NSDI ’13, USENIX Association. [9] Koponen, T., Amidon, K., Balland, P., Casado, M., Chanda, A., Fulton, B., Ganichev, I., Gross, J., Gude, N., Ingram, P., Jackson, E., Lambeth, A., Lenglet, R., Li, S.-H., Padmanabhan, A., Pettit, J., Pfaff, B., Ramanathan, R., Shenker, S., Shieh, A., Stribling, J., Thakkar, P., Wendlandt, D., Yip, A., and Zhang, R. Network Virtualization in Multitenant Datacenters. In Proceedings of the 11th USENIX Conference on Networked Systems Design and Implementation (Berkeley, CA, USA, 2014), NSDI’14, USENIX Association, pp. 203–216. [10] Monsanto, C., Reich, J., Foster, N., Rexford, J., and Walker, D. Composing Software Defined Networks. In Proceedings of the 10th USENIX Conference on Networked Systems Design and Implementation (Berkeley, CA, USA, 2013), NSDI ’13, USENIX Association. [11] Peterson, L. L., and Davie, B. S. Computer Networks, Fifth Edition: A Systems Approach, 5th ed. Morgan Kaufmann Publishers Inc., San Francisco, CA, USA, 2011. [12] Sherwood, R., Gibb, G., Yap, K.-K., Appenzeller, G., Casado, M., McKeown, N., and Parulkar, G. Can the Production Network be the Testbed? In Proceedings of the 9th USENIX Conference on Operating Systems Design and Implementation (Berkeley, CA, USA, 2010), OSDI ’10, USENIX Association