2014：超越炒作，进入部署SDN的时代（David Ward中文版序）
本书英文版第一版在2013年出版之际，我们看到了很多新的SDN产品、体系结构、营销活动和各种会议，一些新的标准和开源组织也进入了这个领域。当时的SDN刚刚从炒作周期的高点回归下来。转眼到了2014年，这一年我们会看到实实在在的产品被采用，包括多个行业的开发和部署。真正重要的是，我们看到了开发者、网络工程师、学术机构、标准组织、合作伙伴的协作达到了高潮，而众多厂商行动的速度也是进入21世纪以来在网络和基础设施行业前所未见的。人们可以感慨地说，这就是软件（SDN中的S）的速度啊！2014年过后再进入2015年，这一切又将有很大改观，因为随着进入炒作周期的“后SDN ”阶段，人们的关注点将从产品和体系结构迁移到完整的解决方案和部署上。我们已经在多个会议、编程马拉松，以及随后的学术论文和白皮书中，看到了很多有关部署成功或失败的案例。
SDN是网络体系结构的一个重要支柱，NFV（Network Function Virtualization，网络功能虚拟化）也一样。随着更加开放、更便于互操作的基础设施和解决方案快速得到采用，我们还将看到多个平台和社区基于这些体系结构涌现。在互联网的这一次转型中，SDN很明显不是一个独立的技术。SDN、NFV和云服务编排，现在都是捆绑在一起作为服务和解决方案交付的。部署路由和信令协议、作为一种可行的技术来实现自动化，以及运行长期部署的控制平面软件等SDN应用已经有了很大的需求。虽然用SDN的说法，这是“混合”的网络，但在现实中这就是常态。当前人们正在讨论的SDN和编程接口，在传统网络的所有层正逐步得到规范化，大量工作集中在传输、线路、服务开通领域以及路由和MPLS领域。流感知技术与民用和商用服务相结合，催生了许多令人激动的成果！社区和标准组织已经加速转变，正致力于资源管理和建模、故障和性能分析乃至综合分析，以及针对广域网和接入网的经验担保及和谐安排。在这些基础之上，产业界下一步的重点显然是要从试验向实际部署产品迈进。
有所改变的是，数据中心并非唯一的谈论焦点。不是一切都将走向大型数据中心。世界将是“多云”的，这些云会因网络拓扑形状和距离、传输比特的开销、法律法规和新的数据分发规则，以及国家和行业的不同而不同，因为隐私和安全是这个世界的中心。此外，企业IT部门对使用编程接口和控制器都已经习以为常了。利用编程接口的效率高、实用、省时间，以及多环境下的一键式服务部署和SLA保证应用，都是企业所看重的。大学校园、分支机构、中小型企业和咨询机构都在利用SDN的优势。这一年的变化太大了！
有一个主题没有变，那就是开放的（标准、源代码和生态系统）、可互操作的组件和体系结构，将为服务和内容提供商及企业催生出新的市场。随后，我们看到以前需要几周来构建和部署的虚拟服务，由于新产品进入网络中的不同位置，现在只要几分钟就可以完成，这又会创建出新的市场。我真正期待的是技术和业务的组合，以前他们是被分割的，现在走到一起创建新的市场。例如移动网络里的视频服务，购物推车式的按需点击部署的安全功能，以及实时协作技术，无论什么内容，什么设备，如何访问和在什么地方。新的接口和门户将这些服务与最终用户连接起来，网络产业界正在部署的SDN和NFV会让这一切成为现实，而且更简单更自动化。
但是，我们还要面对新的挑战：应用程序和内容开发人员，以及最终用户，都不希望把网络当成自己必须了解的东西。对于一名网络工程师，这意味着最终有一个应用程序或工作负载给网络发出信令，告诉网络用户期望通过自己的应用和服务获得什么“体验”，然后网络自己通过编程就能满足用户的需求。于是，不再是网络试图猜测和反应，不再是需要长期的服务开通配置周期。你觉得这很疯狂吗？这是SDN运动2015年要达到的新目标，目前标准组织和整个开源社区正在为此展开广泛的讨论。
许多这些新服务都要依赖OpenStack和OpenDaylight项目，它们是这个生态系统中的两个大型社区。2013年和2014年，它们以SDN沙盘试验场的形象登场，与传统标准制定组织分庭抗礼。开源社区加大发展步伐，使得从概念验证到开发和产品的速度比以前更快。“让可运行的代码来证明”成为新的口头禅（这也是20世纪70年代、80年代和90年代IP开发者的口头禅）。开源显然已经成为一种制定标准的新方式。更多的个人、企业、服务提供商、合作伙伴、供应商和用户参与进来不仅可以集思广益，而且通过利用这些开源解决方案，还可以让这个生态系统和解决方案更加开放。参与者越多，这个生态系统及其产生的解决方案就越开放。结果就是更快、更稳定的解决方案会由多个社区开发出来，这一切都建立在SDN、NFV和云服务编排的基础上。当然，今年乃至未来，这个沙箱的运转会加速，新的论坛、行业联盟将会出现。速度之快，可能会像我们有目共睹的2012年和2013年SDN新协议的发展一样。
2014年，SDN和NFV将超越炒作阶段，进入实际部署阶段，并扩散到新的网络位置和服务。新的生态系统正在推动更多的服务聚合（mash-up），催生创业公司和新的个性化的软件平台和云环境。新SDN和NFV云平台必须是可编程的、健壮的、开放的、可互操作的、虚拟和物理共存的，能够可靠地将接入网与云组合起来。这是我们所有人都需要的网络产业的发展方向。
David Ward
2014年3月26日
英文原文
Intro to Chinese Edition:
2014: Move Beyond the Hype: It's Time to Deploy SDN
We saw many new Software-Defined Networking products, architectures, marketing campaigns and events as well as new standards and Open Source organizations enter the industry in 2013 when the first edition of this book was published. SDN was just breaking through the hype cycle and thankfully now in 2014 we are seeing real products with adoption inclusive of development and deployment across multiple industries. It was truly great to see the culmination of all the work of developers, network engineers, academic institutions, standards bodies, partners, and multiple vendors move at a speed not seen in the networking and infrastructure industry since the early 2000s - one could say that it was the speed of Software. Moving through 2014 and into 2015 will be much different as we'll be “post-SDN” hype cycle and moving from products and architectures to full solution deployments. We've already seen many deployment success/failure presentations at several conferences, hackathons and subsequent academic and whitepapers.
Software-Defined Networking is a critical pillar of the networking architecture as is Network Function Virtualization (NfV) and as we move rapidly forward with more open, interoperable infrastructure and solutions we'll see multiple platforms and communities emerge based on these architectures. As the Internet transitions, it's clear that SDN is not a standalone technology. SDN, NfV and cloud orchestration are now linked together in service and solution delivery. The application of SDN to deployed routing and signaling protocols and as a viable technology to automate and operate long deployed control plane software is now really gaining traction. In SDN parlance it would be a “hybrid”network but in reality it appears the norm. SDN and programmatic interfaces are now being discussed and specified at all traditional layers of network and lots and lots of work is going on in transport, circuit, service provisioning as well as routing and MPLS. The combination of flow awareness and deployed residential and business services is creating a lot of excitement! The change in communities and standards bodies has shifted and we'll be working on resource management and modeling, fault and performance analytics and analytics overall, experience guarantees and orchestrated ties to the WAN and access. It's clearly the next step to get the industry from pilots to deployed products.
What has changed is that the data center isn't the sole focus or conversation; not everything will be moving towards the mega-Data Center. It will be a world of many clouds based upon network topologic shape, proximity, cost of transporting bits, regulation and compliance as well as new data distribution laws on a per-country or industry basis as privacy and security will take center stage. Also the use of programmatic interfaces and controllers in the enterprise IT organization is now commonplace. The Enterprise is taking advantage of the operational efficiencies of programmatic interfaces and useful, time saving, SLA guaranteeing apps and one-touch service deployments that work across multiple environments. Campus, branch, small and medium size businesses (SMB) and smart advisors all utilizing the advantages of SDN. What a change in one year!
One consistent theme is that it will be open (open standard, open source and open ecosystem) and interoperable components and architectures that will drive these new markets for service and content providers and enterprise organizations. We subsequently see new virtualized services that formerly took weeks to build and deploy moving to speeds of minutes with new offerings entering into different positions in the network and creating new markets. I am truly looking forward to the combination of technologies and businesses that were formerly segmented coming together to create these new markets. For example Video over Mobile networks, on-demand shopping-cart-based click-to-deploy security offers, the rise of real-time collaboration technologies and any content, any device, any access - anywhere and everywhere. New interfaces and portals connect these services to the end-users; SDN and NFV enable this to happen with simpler and automated capabilities the networking industry is now deploying.
But let's face it: the app and content developers and end users don't want to see the network as something they have to understand. As a network engineer it means we finally have an app or workload signal to the network what “experience” the user is supposed to get via their application or service and the network can program itself to deliver it. No longer is the network trying to guess and react or requiring long provisioning cycles. You think this is crazy? This is the new boundary of the SDN movement for 2015 and currently being discussed broadly in both standards organizations and across Open Source communities.
Many of these new services take advantage OpenStack and OpenDaylight, which are two of the big Open Source communities in this ecosystem. In 2013 and 2014 they emerged as the sandboxes to work in versus traditional Standards Development Organizations. Open Source has increased the pace of development enabling Proof-of-Concepts to move into dev and production faster than before. The new mantra (which was the original mantra of internet protocol developers in the 1970s, 80s and 90s) being “Prove it with running code.”Open Source has clearly emerged as a new way to standardize. The more individuals, enterprises, service providers, partners, vendors and users not only contributing to but utilizing these Open Source solutions the more open the ecosystems and solutions become. The result is faster and more robust solutions taking shape with multiple communities of developers building towards this - all on the foundation of SDN, NfV and Cloud orchestration. Of course through this year and into the future the sandboxes will shift and new forums, consortiums will emerge; probably as fast we all saw new SDN protocols emerge in 2012 and 2013.
2014 will be the year that SDN and NfV move beyond the hype and into deployments and into new network positions and services. The new ecosystems are driving even more service mash-ups and catalyzing start-ups and new and/or personalized software platforms and cloud environments. The new SDN and NfV Cloud platforms must be programmable, robust, open, interoperable, virtual and physical, linking access networks to clouds with guarantees - and this is what we all need to have happen to move the networking industry forward.
David Ward
March 26, 2014