How does a Software Defined network use OpenFlow?

In recent weeks, with the activation of the Open Networking Foundation (ONF) and the announcement of support for almost all mainstream network providers, the OpenFlow specification broke out in the network field. In fact, the OpenFlow switch has been published on Interop Las Vegas 2011 and has aroused great controversy.

SDN allows network engineers to control and manage their networks so that they can better serve their respective needs, thereby increasing network functions and reducing operating network costs. Open Networking Foundation supports OpenFlow specifications, which will ultimately implement the network that defines software.

What are OpenFlow specifications?

OpenFlow is a software API that allows a "controller" to send configuration information to a vswitch. This configuration usually refers to a "stream" and some "operations" attached to it ".

"Stream" is a set of defined frames or data packets similar to an MPLS stream) and a group of operations. For example:

Source IP/Port, Destination IP/Port, and Drop.

Source IP, Destination IP, and QoS Action.

Source MAC, Destination MAC, and L2 Path.

With OpenFlow, you can send a set of rules to the vswitch or vro of a "configuration" device. Each device then uses the data according to its type. The vswitch updates its MAC address table to forward frames. The vro adds an access list and the firewall updates its rules.

What is a software defined network?

When organizations migrate network configurations from devices to software platforms, vswitches become simpler and cheaper. However, the main benefit is that the network configuration can be managed by the central controller.

The controller is a software that contains algorithms, mathematics, analysis, and rules. It comes from rule groups and uses OpenFlow to download configurations to network devices. Therefore, when the Controller evaluates and rebalance the configuration, the network may be reconfigured dynamically. This is the so-called software defined network.

How will various vendors use OpenFlow?

At the Interop 2011 exhibition, many vendors were promoting their own OpenFlow switches and controllers. The popularity of these switches is self-evident. Are all vendors actively responding? This article analyzes how suppliers such as HP Networking and Cisco use OpenFlow.

HP Networking: HP has invested a lot of resources in OpenFlow. I have seen a demonstration of a QoS function submitted by HP to the Committee, and the company has developed a comprehensive software plan for the controller platform.

NEC: You may not have heard that NEC is also a network vendor, but the company has a complete product series and has started selling in the NEC U.S. market. NEC has made several significant contributions to OpenFlow and has a complete series of switches that support OpenFlow. On Interop, NEC demonstrated its OpenFlow controller.

Cisco: although the network giant is one of the members of the Open Networking Foundation, I still cannot find its plan for OpenFlow. Cisco may think that OpenFlow damages IOS software as a profit-making product. The most prominent advantage of OpenFlow is to reduce the cost of hardware switches, rather than improving the sales of network providers.

Avaya: although the company has made great efforts in the Shortest Path Bridging strategy, I know that the company does not have any plans for OpenFlow.

Arista: neighboray does not have any release plans for OpenFlow, and it also points out that it is impossible to manage all streams on a device. Although Cisco thinks so, I think this is a misunderstanding of the way OpenFlow works. It is possible to use OpenFlow to process each stream, but this is not necessary. This is just a configuration option.

Big Switch Networks: this newly established company focuses on OpenFlow solutions, especially network virtualization. Although the Big Switch website does not have any details, I think they are developing controllers and switches.

If OpenFlow can have enough customers, it will fundamentally change the network industry, because the control protocols we currently use, such as OSPF, Spanning Tree, or DCB) will be replaced by the software controller. Although this will promote the commercialization of hardware, software controllers will become a new part of the network industry. The software's functions, features, and reliability will be the key to determining whether OpenFlow is successful or not.

What is this software doing on my network?

If there is a general topic for my conversations with the guests at Interop, software is the future of the Internet. It can be said that this has always been the case. Even in the best switch rack, code drives its operation. Until this year, OpenFlow specifications-a few months ago it was just a research project at Stanford University-are currently a hot topic, and most network providers are scrambling to announce their software-defined network strategies, or follow closely due to public opinions.

Even if there is no network virtualization, only software network devices have been transformed from a development/test environment method to products that support the production environment, which is obvious. On Interop 2011, every vendor I talked about was promoting the virtualization version of their hardware. For example, Infoblox talked about virtual IP address management and configuration management products, while BlueCoat talked about virtual WAN optimization and security devices.

Cloud-based network management-basically software-driven-was also involved at Interop. For example, PowerCloud introduced how its technology enables OEM partners to manage cloud-based wireless access points at the venue. As a result, managed service providers can compete positively with companies such as Aerohive and Meraki. By adding a small amount of code to their firmware, the access point can "call" the host service and connect to a specific customer with a unique identifier. In many aspects, cloud-based management can provide enterprise-level features and functions to the SMB market without the need to spend the same amount of money as large WLAN hardware solutions.

Cisco also discussed cloud management WLAN at Interop, which introduced its new system. The new system allows enterprises to manage the AP of thousands of branches through a centralized private cloud. In the era dominated by hardware, switching to software is a logical method. The flexibility requirements in the era of virtualization will become the only challenge for hardware. Its future development deserves our expectation.