软件定义的网络现在已经是几年的热门对象，并且从开始讨论正确指出的是，SDN的密钥特征是从数据转发平面中的至少一些数据控制平面的分离。然而，在其他时候，讨论似乎错误地等同于SDN和OpenFlow或SDN和网络虚拟化。而且，如此经常发生在这个行业中，最初的SDN文章在科技将被广泛采用的方面存在着概括。
我们最近完成了一项调查of 246 IT professionals – The 2015 Guide to SDN and NFV – to get a better handle on what’s driving interest in SDN, the opportunities and impediments, and where, how and when companies plan to pursue the technology.
关于它们可能拉动触发器时，调查受访者获得了多项选择问题，并要求表明描述其实施SDN方法的替代方案。允许多次答案，他们的回复如表1所示，与同类对类似的受访者群体给出的同一问题的回答。
表1表明，虽然生产网络中SDN的利用仍然有限，但它在去年增加了一些显着增加，并且应该在明年再次增加一些。这引起了问题，是什么推动兴趣？将部署SDN在哪里？将如何部署？什么时候被广泛采用？
What’s driving the interest in SDN?
调查参与者被问及他们认为SDN可以解决哪些机会（见表2）。事实证明，相当多。它通常持乐观态度，但有趣的是，相对少的人认为SDN将帮助他们降低资本支出或降低复杂性，这是早期期望。
识别SDN的司机是现代人理解的关键ding its status, but so is identifying the impediments that stand in the way of broad adoption. With that in mind, survey respondents were given a list of impediments and asked to identify the two that would be the biggest inhibitors to adopting SDN sometime in the next two years. Given the state of the industry, it isn’t surprising that the immaturity of the available products topped the list (Table 3).
显然，产品的成熟和使能技术将随着时间的推移而改善。然而，一些其他关键抑制剂不仅仅是自然消失。这些抑制剂需要由供应商和网络组织进行积极解决，包括关于如何将SDN整合到遗留基础设施以及缺乏引人注目的业务案件的担忧。
How will SDN be deployed?
While the initial discussion of SDN focused on implementation in the data center, the scope has now widened. In order to understand where SDN will likely be implemented, survey respondents were asked, “If your organization is likely to implement SDN sometime over the next two years, where are you likely to implement it?” Their responses (Table 4) indicate that the primary focus is likely to be in the data center, however there is considerable interest in the WAN as well as in branch and campus networks.
还要求受访者表示从现在开始普及的SDN在他们的校园，WAN和数据中心网络中有多普及。雷竞技电脑网站他们的回答（表5）显示了数据中心的标记导入，但在WAN和校园网络中也有重大部署。雷竞技电脑网站鉴于SDN部署的当前状态（表1），这些渗透率似乎过于乐观。
How will SDN be implemented?
供应商SDN产品之间的主要架构差异之一是它们的实施方式。VMware和核磁网络等公司提出的覆盖模型专注于虚拟机管理程序和隧道和封装。基于织物的基于底层的模型侧重于一系列虚拟和物理网络元素，并依赖于SDN控制器操纵网络元件中的流量表。这是思科，NEC和HP等公司使用的模型。
Survey respondents were asked what relative value the overlay- and the underlay-based models will provide over the next two years. Their responses (Table 6) indicate, by a small margin, IT shops perceive the fabric-based SDN model will provide more value. However, many have yet to form an opinion.
Another one of the architectural distinctions between the varying ways vendor implement SDN is the role of dedicated hardware. Vendors such as VMware believe it’s possible to fully support network virtualization in the data center without using dedicated hardware. In contrast, vendors such as Cisco believe dedicated hardware is needed in at least some instances. The survey respondents were asked if they believed that, with the current technologies and products, it’s possible to broadly support network virtualization in the data center without using any dedicated hardware? Those that believed it was not possible outnumbered those that believe it is by almost a 2:1 ratio.
OpenFlow关键？
At one time many equated SDN and OpenFlow. To understand how IT organizations currently view that relationship, survey respondents were asked how likely it was that OpenFlow would play a role in their SDN implementation (Table 7). Most seem to have a favorable view of OpenFlow, but almost a third are still on the fence. (See related文章。）
And finally, we asked about the relationship between SDN and Network Function Virtualization. Until recently, the conventional wisdom was SDN and NFV were separate topics and didn’t need to be formally coordinated. That changed in March 2014 when the Open Networking Foundation (ONF) and the European Telecommunications Standards Institute Industry Specification Group for NFV (ETSI NFV ISG) announced the signing of a Memorandum of Understanding (MOU). As part of that announcement, the ONF and ETSI stated that “Together the organizations will explore the application of SDN configuration and control protocols as the base for the network infrastructure supporting NFV, and conversely the possibilities that NFV opens for virtualizing the forwarding plane functions.”
调查受访者被要求表明他们公司在SDN和NFV之间看到的关系，并且允许他们检查所有适用的所有关系。他们的答案（表8）表明绝大多数IT组织认为SDN和NFV是免费活动，并且在至少一些实例中，NFV至少需要一个重要的百分比要求SDN。这意味着它的IT组织的相对较大的百分比将以他们的NFV实现，至少松散地绑定他们的SDN实现。
Early in the discussion about emerging technologies IT professionals tend to be optimistic about when the new tech may be widely adopted, which happened with SDN. However, the further into the development the more realistic adoption estimates become. Our research indicates SDN won’t be broadly adopted until there are mature solutions, well understood and accepted business cases and a set of best practices relative to how to integrate SDN into the rest of the infrastructure. That won’t happen in 2015 and may not happen in 2016.
Metzler已从运行企业网络到设计网络，开发软件和运行咨询组织的所有内容。他目前的兴趣包括应用程序交付，软件定义的网络（SDN）和网络功能虚拟化（NFV）。jim@shtonmetzler.com.
