Application scenarios of SDN switches in cloud computing networks (1)

Application scenarios of SDN switches in cloud computing networks (1)

 

The SDN technology has been developing for several years, and the history of cloud computing is longer. The combination of the two is even more popular as a killer application of SDN in the past two years, some well-known consulting companies have come to the conclusion that SDN has increased its market share year by year. It mainly refers to the application of SDN in cloud computing networks.

SDN applications in cloud computing networks currently have two main schools: one is the "soft" school represented by VMware, and the other is the "hard" school represented by Cisco. The former mainly means that the core logic of the entire network virtualization solution is implemented on the Hypervisor of the server, and the physical network is just a pipe; the latter refers to the realization of the core logic of network Virtualization in the physical network (the top switch of the main edge, that is, the TOR ), only the parts that cannot be implemented by the vswitch can be placed on the server or other dedicated devices. The two solutions have their own merits and fans.

However, the world has never been a single pole, nor a polar pole, but a multi-pole. There are many unconventional demands in the real network. These demands cannot be solved by these two solutions, or even though they can solve the problem, they are not optimal, including implementation difficulty, performance, and price. As a practitioner who has been using hardware SDN for a long time to provide solutions for users, I would like to introduce how hardware SDN switches in the real world can meet the specific needs of some cloud computing networks, these requirements may be met by both public and private clouds. Private clouds (including hosted clouds) are mostly used because custom requirements are more common in Private clouds.

We need to note that all of these scenarios can be achieved with Cisco's ACI, because the idea of ACI is to use hardware SDN to support network virtualization. However, many users do not want to use cisco ACI for various reasons (for example, the price is too high, the vendor is locked, and the localization trend), so they need another solution (I am not saying that ACI is not good, on the contrary, from a technical point of view, I personally appreciate ACI ).

Cloud computing network customization requirements for SDN controllers and switches

Many people may misunderstand the application of SDN switches in cloud computing networks. There are two typical misunderstandings: one is that someone asks, Which controller do you use? Can it be connected to OpenDayLight/Ryu/ONOS? The other one is that we feel that we can use an SDN switch to support cloud computing network scenarios, regardless of the vendor's SDN switch. These two misunderstandings are caused by the fact that many people do not understand SDN, which means application-related customization. They think that they can use a general thing to create a cloud computing network. As a specific SDN scenario, cloud computing network controllers are usually designed specifically for the cloud computing scenario. A single function is to meet the needs of cloud computing networks, it may not even be an explicit controller, but hidden in the cloud platform (for example, code logic directly implemented in OpenStack Neutron Server ). Controllers in this scenario cannot be used as general SDN controllers. On the contrary, General SDN controllers cannot be directly used in cloud computing network scenarios. As for the second question, it is easy to understand why it is a misunderstanding. Even controllers must be customized for cloud computing scenarios, not to mention SDN switches. Therefore, instead of using an SDN switch to support cloud computing network scenarios, you need to have specialized in-depth customization. For example, Shengke network has designed the corresponding controller and switch functions for this scenario.

Scenario 1: Use a hardware SDN switch to improve performance

In this scenario, you can use Tunnel Overlay to deploy network virtualization. However, the vSwitch has a great impact on the performance of Tunnel (VxLAN or NvGRE) Operations (low throughput, high latency, and high jitter, the specific impact depends on the implementation and optimization of each company). In this case, you can use the sdn tor switch for tunnel offload, offload the tunnel operations that have a major impact on the performance to the sdn tor switch. All other operations remain unchanged on the server. Logically, we can think that the sdn tor switch is an extension of the vSwitch. Further, you can place the distributed east-west L3 Gateway on the sdn tor, so that the sdn tor is deeply involved in network virtualization.

Not all users agree on this mode, but some people like it. Currently, this scenario has been deployed in several small and medium-sized private clouds and a famous IDC cloud. The greatest help to these clouds is excellent performance and stability. For the data process, see.