网络的五个趋势正在推动向软件定义的网络和可编程性过渡。
They are:
•用户，设备和应用程序移动性；Cloud computing和service;
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• Consumerization of IT;
•改变数据中心内的流量模式；2020欧洲杯预赛
•和敏捷的服务交付。
跨多个市场的趋势，包括企业，服务提供商，云提供商，可扩展的数据中心 -2020欧洲杯预赛found at Google，Facebook，Amazon等 - 以及学术界/研究。支持者说，他们需要动态的网络适应性，灵活性和规模，并降低成本，复杂性和增加的供应商独立性。
IT'S BIG:OpenFlow and SDN: Networking's Future?
According toCisco，刚刚释放了一个可编程架构, enterprises need network programmability to automate the operation of private cloud deployments. These deployments include virtual workloads, virtual desktop infrastructures, and the orchestration of安全profiles across them.
And within the enterprise2020欧洲杯预赛, traffic patterns have changed from the "north-south" directions of client/server到“东西方”，其中申请在将数据交付给客户端之前，请访问不同的数据库和服务器。The Open Networking Foundation says this, as well as the increasing use of personal devices to access corporate data -- the BYOD phenomenon -- and the deployment of private, public and hybrid cloud infrastructures and services is also changing traffic patterns, requiring the automation, rapid reconfigurability and simplified extendability SDNs provide.
其他SDN/可编程/网络虚拟化players say SDNs and the applications they enable can relieve VLAN exhaustion, facilitate data center interconnect and disaster recovery, allow for granular, policy-based security, network isolation, service interposition, deterministic application performance and customization,among others. Policy-based security is particularly important to the BYOD trend; as the ONF notes, enterprise IT is under pressure to accommodate personal devices in a fine-grained manner while protecting corporate data and intellectual property, and meeting compliance mandates.
Service providers need SDNs for agile service delivery, proponents say. SDNs and network programmability can enable policy-based control and analytical data capture to help optimize and monetize service delivery, they say. Cloud service providers and webscale companies like Google, Facebook and Yahoo to ease or automate network configuration and reconfiguration, and quickly add more functionality without manually touching each and every switch orrouterin the network.
Such companies can use OpenFlow and SDNs to reroute traffic, balance traffic loads, provide bandwidth on demand for peak requirements, execute policies to scale and segregate the networks of different data center or cloud tenants, and connect subscribers to content and services. Cloud providers in particular require programmability to support scalable multi-tenant environments through automated provisioning and virtualization overlays that abstract complicated and distributed physical infrastructures from function.
From an IT perspective, deployment of and access to cloud services can be facilitated by SDNs that enable "elastic scaling" of compute, storage and network resources using a common suite of tools from a common viewpoint, according to the ONF. This is particularly important as organizations stress increased security, compliance, and auditing in cloud environments, or when abrupt changes emerge as businesses reorganize, consolidate or merge.
Massively scalable data centers are said by Cisco to require network flow management enabled through customization using programmatic APIs to provide deep insight into network traffic. And academia and research require network "slicing," or partitioning to separate experimental network use -- i.e., to investigate applicability of OpenFlow or SDNs -- from production networks.
在这两种情况下，大数据在需要SDN或网络可编程性中都起着关键作用。SDN可以帮助引导数千台服务器之间的流量并联处理大量数据集；并可以帮助数据中心网络更有2020欧洲杯预赛效地扩展，同时维护服务器到服务器，服务器到存储以及服务器/存储网络连接。
无论需要什么要求，当今的网络都不符合提供SDNS承诺的适应性和规模的任务，根据ONF：
"The explosion of mobile devices and content, server virtualization, and advent of cloud services are among the trends driving the networking industry to reexamine traditional network architectures. Many conventional networks are hierarchical, built with tiers of Ethernet switches arranged in a tree structure. This design made sense when client-server computing was dominant, but such a static architecture is ill-suited to the dynamic computing and storage needs of today's enterprise data centers, campuses, and carrier environments."