OpenFlow承诺使网络更可编程和一个早期用户正在收获的初始收益。
Genesis Hosting Solutions of Lake Zurich, Ill., implemented OpenFlow in February to make its network more flexible and easier to configure. It helps the hosting provider deal with a large number of VLANs and overcome the challenges of Spanning Tree's reconvergence time in a network. OpenFlow also helps Genesis establish redundant connections while maintaining performance.
"It basically creates a network without loops in a mesh configuration, but without Spanning Tree," says Genesis CEO Eric Miller. "That was really exciting to us."
FAQ:What is OpenFlow and why is it needed?
OpenFlowis a protocol that enables software-defined networking, which means that users can define flows and determine what paths those flows take through a network, regardless of the underlying hardware. OpenFlow can take control of how traffic flows through a network out of the hands of the infrastructure -- the switches and routers -- and put it in the hands of the network owner, individual users or individual应用.
此功能可以让用户到找到可用的带宽，更短的延迟或拥塞，并且跳数少的路径制定政策。OpenFlow的支持者称它是负载均衡是特别有用的，流于数据中心，私有云和其中设备正在日益增多，使劲的网络拓扑结构像生成树拓扑改变后，可以采取数十秒重新收敛校园局域网控制和虚拟网络。雷竞技电脑网站
OpenFlow, the result of a six-year research collaboration between Stanford University and the University of California at Berkeley, uses a centralized controller to process those reconfigurations on behalf of OpenFlow-enabled switches.
Genesis finds that OpenFlow can reroute traffic around deactivated links between cascaded switches, or around some anomaly downstream that can't be detected through link "beaconing" techniques, which ping for link status but might lack rerouting capabilities. With an API into switch tables, OpenFlow controllers allow Genesis to easily steer traffic around trouble spots and overly congested links, and control the entire switch fabric "from a bird's eye view," Miller says.
INSTANT EXPERT:All you need to know about OpenFlow
OpenFlowalso allows Genesis to create policies based on its hosting customers. These policies can be easily added to or removed from the entire switching fabric so provisioning and de-provisioning of network resources for customers can be achieved through a single API call, Miller says.
米勒说，能力“非常高兴能够听到”当他最初评估OpenFlow的。“你听到一个技术，你问，‘很好地接受它是如何，如何实现呢？’我们会实现它在一个小论坛，只是为了看看它如何工作。”
So far, it's working as advertised, he says. Genesis has two NEC ProgrammableFlow controllers -- one for redundancy -- in its Chicago雷竞技电脑网站理事2 NEC 48端口，1Gbps以太网交换机ProgrammableFlow。环境是支持2500个的虚拟机。
托管服务提供商计划重复这种设置在展望山，伊利诺伊州。第二个数据中心，并建立了芝加哥和展望山控制器之间的故障切换功能的点至点二层雷竞技电脑网站链路以及其它功能。成因是希望只对特定业务或流创建开放流控制器，将彼此独立地操作，但共享表的联合。关键是，这将是一个内存镜像功能NEC正在开发，将允许两个控制器保持状态。
Currently, failover between one controller and another takes a few seconds, which requires controllers to re-create tables once they come back up. Memory mirroring could solve this by replicating the flow table between the two or more controllers, which would expedite failover, Miller says.
Even though the implementation is running smoothly, there were a few initial hiccups, Miller reports. For example, Common Address Redundancy Protocol, or CARP, advertisements from redundant routers to the Genesis VLANs were disrupting the operations of one of the default OpenFlow controllers. Miller, though, says this was minor and quickly corrected.
另一个潜在的担忧是OpenFlow的控制器是在网络中计算的单一的点上，旨在通过所有的网络路径的创建隧道重新建立中断的流动，米勒说。已经有一些业内人士的讨论，参与动态创建这些隧道可以压倒控制器的计算，他说。
“但我们个人还没有看到任何限制呢，”米勒说。“我们还没有在流程创建方面刷爆了出来。”
The next step for Genesis will be to replace 30 legacy edge switches with 24/48-port 1G edge switches that are OpenFlow-capable to enable the hosting provider's entire network to be OpenFlow software programmable. Currently, these switches support 1,200 Gigabit Ethernet ports, and NEC only manufactures OpenFlow core switches.
“我们正在做的优雅，对于明显的原因，因为它是一个新的技术，”米勒说。“我们希望有失败，在最坏的情况回到我们的传统网络的能力。”
But so far, the hosting provider has had no major issues with OpenFlow and is looking forward to broadening its implementation.
"Treating the network as a single entity, not a large number of individual switches, is the goal that we're after," Miller says.