Can the Software Definition network (SDN) solve the problem of private cloud network bottlenecks?

You've heard it, but it's worth repeating that the network is a bottleneck in a private cloud. Now that servers and storage technologies have developed into shared resources, cloud administrators are free to invoke these resources, but the network is still manual. To improve flexibility, private cloud networks must be virtualized, and software definition networks (SDN) are a cost-effective approach. "Businesses need to respond quickly, like service providers, to internal customers. To do this, the enterprise needs to enable self-service it, and the biggest obstacle to achieving this is the network, "said Ben Cherian, a start-up company based in SDN network virtualization technology, Midokura," Many employees with CCIE qualifications may take weeks to make a few changes to switches and routers, while in many cases the cloud service provider needs only one button to make changes. "Essentially, SDN technology is decoupled from the data forwarding plane of a single network device and centralizes the control plane. Through a centralized control plane (usually on a server-based SDN controller), the network becomes more programmable, which creates a more dynamic and reliable private cloud network. "Much of the disruption we've experienced stems from man-made errors," says Brent Salisbury, a network architect at the University of Kentucky. "If we can make network changes programmable and updatable, it will create great value for us while avoiding human error." "Salisbury has been testing SDN with private cloud technology in its test and development environment. The OpenFlow protocol is the most well-known way to decouple and centralize networked control planes, but the availability of the mainstream business version of OpenFlow-friendly switches is limited, and most data products from Cisco, the world's largest switch provider, are not yet supported by the technology. As a result, SDN suppliers have taken different approaches to bringing the technology to market. NEC, for example, made its own switch for its openflow controller. On the other hand, big Switch NX and Nicira NX (recently acquired by VMware) Create SDN coverage by centralizing the control planes of virtual switches based on hypervisor. It then communicates through a physical network of protocols such as Vxlan (virtual extensible LAN) and Nvgre (Network virtualization with Universal routing encapsulation). A company based on SDN Private Cloud network The Dutch IT management and consulting company Schuberg Philis has faced a private cloud network problem: The company built an internal cloud through a flexible computing pool, but manually configured the network. "For a long time, we have built a private cloud through a virtual host, a virtual host with great flexibility, but every time IAs we begin to use this flexibility, we all find that we have to turn to network engineers, ' before we use the cloud services, we need another virtual local domain network or another port configured in another VLAN '. "Now, the company is building its internal cloud based on SDN technology. This new cloud infrastructure includes a high-speed 2-tier network, a Arista switch and a Nicira network virtualization platform (NVP). The company started small, with a dual 10,000 Gigabit Ethernet Arista Switch Two server racks, switches uplink to a pair of terminal switches. "The only thing you need to do in a nicira solution on a physical network is a quick swap, and Arista is the fastest switch we've ever found, it's a completely flat 2-layer network with very few VLANs to connect to the public Internet," says Prippaers. "Nicira's NVP technology creates a SDN overlay between the virtual switch and the physical 2-layer network on the hypervisor host in the server rack, which covers 2-tier networks as the backbone of the IP, allowing 3-tier network traffic and other network services to pass through it. Therefore, the Schuberg Philis administrator can change the SDN overlay by clicking a button when the cloud service is started without having to make changes to the underlying physical network. "With Nicira solutions, network people can build the entire network infrastructure in the way we want, without having to reconfigure the physical devices, which saves us a lot of time," Prippaers says. "Our network engineers are now able to focus on the core work of the network, Ensure the interconnection is perfect and the speed of 2-layer network Exchange. They now need to focus on the most important things, instead of changing the port configuration and other trivial things. "Sdn Cloud Network: Choreography requires north-to API although SDN technology can virtualize networks and simplify network management in private clouds, network operations can still be separated from other work by the cloud infrastructure team. To simplify operations, SDN must be integrated into the cloud Orchestration framework, experts say. Eric Hanselman, head of 451 Group Network Research, says SDN may be more complex to manage, "at a lower level, openflow available, but for big Switch, NEX and Nicira, the real value lies in higher levels of control." No one wants to use several tons of Python scripts for network control. If you want SDN to be part of the top-level control environment, it is only possible to integrate SDN to a higher level to achieve real value. "The Open Networking Foundation (ONF), which manages OpenFlow development, recently acknowledged the need for such integration, announcing the extension of its SDN standardization scope to focus on the North API. OpenFlow is considered to be a south-direction protocol that allows the SDN controller to communicate with the following switching infrastructure and control these infrastructures. ButThe North API is the connecting controller to the application and the choreography framework above. For example, the North API allows the cloud orchestration system to manipulate the network through the OpenFlow controller. Hanselman said: "OpenFlow is committed to the application infrastructure itself (whether it is the actual application or the launch of the application Management environment) will be able to dynamically control the network configuration, connectivity, and the allocation of what functions and capacity. We have to use the programmable way to break down network resources into expendable resources with computing and storage, and that doesn't need to know what the hardware is. "We're not going to start programming static streams in SDN, but that's worse than static routing," says Salisbury of the University of Kentucky. That's 1 million times times finer grained, I think the North application is the only way to integrate SDN into the cloud choreography. "Nicira plus OpenStack to deal with the problem of a multi-tenant private cloud network to address the North API in its private cloud, Schuberg Philis integrates Nicira technology with cloudstack-Open source cloud Orchestration framework created by Citrix. This integration allows the company to create and manage multi-tenant networks in its private cloud. "With the cloud management system, we can create a multi-tenant environment where each tenant can create multiple networks," says Prippaers of the company, "We have integrated the Nicira solution so that Cloudstack provides you with a network, It then uses the Nicira API (application programming Interface) to create a logical switch. Each virtual machine that is started in the network is then assigned a logical port and connected to the virtual switch. "Programmability with proprietary SDK is feasible, but SDN better over the years, network vendors have tried to provide some degree of programmability-usually through the Software Development Kit (SDK) built on their operating systems. For example, Cisco's SDN strategy includes one Platform Kit (ONEPK), an SDK for all of its network devices, which is programmable. However, Salisbury does not want a programmable cloud network based on proprietary APIs running in proprietary software on proprietary hardware. "By OpenFlow, you now have better visibility and more control over the forwarding plane," says Salisbury. "He wants companies like Cisco and Juniper to fully support openflow so that customers can freely build the networks they want," he said. In this regard, he points out, Google has not been sitting on its own, but has built its own openflow devices, including switches and controllers. Some people doubt that the SDN centralization concept for OpenFlow support, the entire industry has been relatively conservative, because the SDN control plane of the centralization problem still exist. Some vendors and network engineers question the scalability and security of centralized control. Salisbury said: "SomeSuppliers are always distributed because they think centralization is not feasible. But he points out that in the wireless LAN market, centralized, host-based networks seem to be working well. For Salisbury, the current network architecture is too complex to meet the needs of a private cloud environment. "We use the Internet architecture, apply it to the corporate network," Salisbury said: "We use the Internet's huge protocol stack, and the huge distributed computing model, thinking, ' This applies to hundreds of thousands of autonomous admin domains, we should be able to put the same architecture in one admin domain. ' But it's becoming very complicated, and I think SDN is inevitable, we've been behind for 10 years, and now we've got a roadmap, the only question is, can we achieve this faster than the x86 market? ”