An SDN-based Network Virtualization Architecture Using LISP

The need for advanced network control functions such as traffic Engineering, service insertion and service chaining, multi-tenancy, and tenant isolation are increasingly growing as Network Virtualization becomes the dominant trend in the Data Center and Cloud. The rise of such new requirements has exacerbated the inadequacy and lack of flexibility of today’s network management and control mechanisms especially in the face of rapidly changing virtualized networks. Software-Defined Networking (SDN) has emerged as a general paradigm based on decoupling and refactoring the network management and control logic from the network devices. This refactoring of the network control plane facilitates unifying the elementary functions such as element discovery and state distribution across various network applications. Furthermore, it enables and promotes the design of network management and control logic based on a global network view [6]. Enabling such logically centralized control plane, together with providing open interfaces to the network switches and routers gives the promise of improving the state of the art, by making it easier to extend and introduce new network control functions [7]. Nevertheless, during the past few years, the shift from fully distributed control planes to logically centralized network control hasn’t been without challenges. While centralizing management functions clearly simplifies network management, logically centralized control planes tend to face limitations in scalability. As a result, physical distribution is used as a scaling enabler for such logically centralized control planes. However, research shows that there is a clear trade off between network application performance and application complexity when taking into account this underlying state distribution of the logically centralized control [8]. Consequently we ask the following: how much of the control logic needs to be refactored to achieve the right balance of flexibility and programmability vs. scalability and robustness? While responding to this question requires extensive research and experimentation, in this talk we will describe how we leverage the Locator/ID separation Protocol (LISP) [4] architecture to implement a network virtualization solution that also provides decoupling of the control plane from the data plane. The core of the LISP architecture lies in its Mapping System, where policies can be defined programmatically, and are fetched and enforced by network switches/routers as flows arrive. We elaborate on how this technology, integrated with a centralized network management framework, can be used to enable new control requirements raised by network virtualization such as multi tenancy, tenant traffic segregation, and VM mobility, as well as network programmability capabilities such as traffic engineering and service chaining. LISP implementations are available in the open source community including LINUX and FreeBSD.