NeTS: Small: Exerting Logically Centralized Control over Legacy Switches via Incremental SDN Deployment

新兴的软件定义网络（SDN）范式正在迅速塑造网络领域，无论是在学术研究还是工业发展方面。由于其诸多优点，SDN最早的采用发生在数据中心网络中；它也被应用于广域网（wan）。然而，Internet上的绝大多数网络都是企业网络，SDN的部署面临着重大挑战。大多数企业网络由传统的以太网交换机组成，其中IP （Internet Protocol）路由器主要用作网关，在IP子网之间进行路由，并连接到校园IP核心网，以实现外部Internet连接。这些企业经常运行依赖于遗留硬件设备和/或软件组件的关键任务应用程序。因此，必须能够在企业网络中逐步部署SDN，以消除或尽量减少对现有服务和应用程序的中断，同时逐步建立信心。该项目提出了一个新颖的框架，用于主要由第2层以太网交换机组成的传统网络向支持sdn的网络的增量和优雅过渡。不需要将传统网络大规模升级为支持SDN的网络，这不仅昂贵，而且可能非常具有破坏性，或者将网络的一部分转换为“SDN网络孤岛”，只允许这些SDN孤岛享受SDN的好处，首席研究员（PI）主张，将传统交换机网络迁移到混合传统交换机和支持SDN的交换机的混合网络不仅是可能的，而且实际上是有利的，同时获得与完全部署的SDN网络一样多的好处。该框架（称为磁化器）背后的关键思想是，通过用网络中支持SDN的交换机替换一个或几个战略性放置的第2层遗留交换机，磁化器SDN控制器可以影响和影响遗留交换机和终端主机的转发行为的变化，从而获得可见性并对这些设备施加控制，而无需对现有遗留硬件设备或软件组件进行任何修改。更广泛的影响：如果成功，该研究项目将提供一个具有成本效益的增量部署框架，以分阶段优雅地将传统网络过渡到支持sdn的网络，这将允许网络运营商在控制和最小化此类过渡的潜在影响的同时逐渐建立信心。它提供了在仅部署少量SDN功能交换机的混合网络中获得完全部署SDN的好处的潜力。这种能力将简化网络管理任务，减少容易出错的人工管理任务造成的错误，从而形成更可靠的网络系统。在更大的社会背景下，更好地管理和保护支撑当今和未来互联网应用和服务的复杂网络的能力将为社会带来重大利益。该项目将积极让本科生——尤其是女学生和少数族裔参与研究项目，例如通过NSF本科生研究经验（REU）资助、本科生研究机会计划（UROP）和项目所在机构的高级设计课程。PI将在公共领域发布软件，以便广泛分发和采用，并参与其他外联活动。

The emerging software-defined networking (SDN) paradigm is rapidly shaping the field of networking, both in terms of academic research and industrial development. Thanks to its many benefits, earliest adoption of SDN occurs in data center networks; it has also been applied to wide-area networks (WANs). However, a predominant majority of networks on the Internet are enterprise networks, where deployment of SDN faces major challenges. Most enterprise networks are comprised of legacy Ethernet switches, where IP (Internet Protocol) routers are used primarily as gateways to route between IP subnets and to connected to the campus IP core networks for external Internet connectivity. These enterprises often run mission-critical applications that rely on legacy hardware devices and/or software components. It is therefore imperative to be able to incrementally deploy SDN in enterprise networks to eliminate or minimize disruptions to existing services and applications while gradually building confidence. This project puts forth a novel framework for incremental and graceful transition of legacy networks comprised primarily of layer-2 Ethernet switches to SDN-capable networks. Instead of requiring a wholesale upgrade of a legacy network to a SDN-capable network which is not only expensive but can be very disruptive or converting portions of a network into "islands of SDN networks" which only allow these SDN islands to enjoy the benefits of SDN, the principal investigator (PI) advocates that it is not only possible but in fact advantageous to migrate a network of legacy switches only to a hybrid network of mixed legacy switches and SDN-enabled switches while at the same time reaping as much benefit as a fully deployed SDN network. The key idea behind the framework -- referred to as magnetizer -- is that by replacing one or a few strategically placed layer-2 legacy switches with SDN-capable switches in the network, the magnetizer SDN controller can influence and effect changes in the forwarding behavior of legacy switches and end hosts so as to gain visibility and exert control over these devices without the need to make any modifications to existing legacy hardware devices or software components.Broader Impact: If successful, the research project will provide a cost-effective incremental deployment framework for gracefully transitioning legacy networks in stages to SDN-capable networks, which allows network operators to gradually build confidence while controlling and minimizing the potential impact of such transitions. It offers the potential to reap the benefits of a fully deployed SDN in a hybrid network with only a few SDN-capable switches deployed. Such capabilities would simplify network management tasks and reduce mistakes caused by error-prone manual management tasks, leading to a more reliable networked system. In a larger social context, the ability to better manage and secure complex networks which underpin today's and future Internet applications and services will bring significant benefits to the society. The PI will actively involve undergraduate students -- especially female students and underrepresented minorities in the research project, e.g., via NSF Research Experiences for Undergraduates (REU) grants, Undergraduate Research Opportunities Program (UROP) and senior design courses at the PI's institution. The PI will release the software in public domains for wide distribution and adoption, and engage in other outreach activities.