In-depth analysis of SDN switch configuration and application issues

SDN (Software Defined Networking) is an emerging network architecture. We can use the architecture and concept of SDN to achieve extensive and in-depth needs without changing any underlying network environment, making the network truly configurable and definable by software. So how to configure and apply SDN switches?

1. Analysis of SDN switch configuration and control technology

SDN adopts the idea of ​​centralized control, which enables the SDN controller to have a global perspective. It can change the forwarding behavior of the SDN switch from the perspective of global optimization and improve network performance. Therefore, SDN switch configuration and control technology are of great significance for data center network traffic load balancing.

1. Analysis of SDN switch control technology

Openflow is the most widely used SDN switch specification. The OpenFlow protocol supports three message types: Controller-to-Switch (controller switch message), Asynchronous (asynchronous message), and Symmetric (symmetric message).

Each message type has multiple sub-message types. Controller-to-Switch messages are initiated by the controller to manage and obtain the status of the switch; Asynchronous messages are initiated by the switch to update the controller with switch status changes and network events; Symmetric messages can be initiated by both the controller and the switch. The sub-message descriptions of each message are shown in the following table.

2. SDN switch configuration technology analysis

OF-Config is the most widely used switch configuration protocol in SDN networks. OF-Config is maintained by the Configuration & Management Working Group of the ONF organization, and version vl.0 was released on January 6, 2012. The main goal of OF-Config is to implement basic functional configuration on network devices that support OpenFlow. In addition, OF-Config has also formulated the operational and maintenance capabilities required in various scenarios and the requirements for switch management protocols based on its own needs. The following will analyze the configuration capabilities of the OF-Config protocol from the above aspects. The basic functional configuration of OF-Config on network devices that support OpenFlow includes: configuring the IP addresses of one or more controllers; configuring the queues, ports and other resources of the device; and supporting remote modification of the port status of the device. The OpenFlow switch configuration capabilities defined in OF-Config are shown in the following table.

In addition, in terms of operation and maintenance, it mainly includes the following four points: support for configuration operations from multiple configuration points; support for one configuration point to configure and manage multiple switches; support for multiple controllers to control the same logical switch; support for the configuration of ports and queues assigned to logical switches. In terms of management protocols, OF-Config has made more detailed provisions, such as the protocol must be secure, ensure integrity and privacy, and provide two-way identity authentication; the protocol needs to support connections initiated by switches or configuration points, support the configuration of some switches; the protocol must have good scalability and be able to provide protocol capability reports, etc.

3. Relationship between SDN switch configuration technology and control technology

The relationship between OF-Config and OpenFlow is that OF-Config protocol is the "companion" protocol of OpenFlow protocol, which solves the OF switch management and configuration standards that are not specified in OpenFlow protocol. In OpenFlow protocol, there is a controller that sends flow tables to OF switches to control the forwarding behavior of data flow, but it does not specify how to manage and configure these OF switches, and OF-Config is proposed to solve this problem.

The role of OF-Config is to provide an open interface for remote management and configuration of OF switches. It does not affect the content of the flow table and data forwarding behavior, and does not have too high a requirement for real-time performance. Specifically, matters such as building flow tables and determining the direction of data flows will be specified by the OpenFlow specification, while operations such as how to configure the controller IP address under the OpenFlow switch and how to configure the queue on the switch port will be completed by the OF-Config protocol. The relationship between OpenFlow and OF-Config is shown in the following table.

2. SDN switch application and configuration

SDN switches use virtual network device technology, which can not only extend the data link layer, but also realize a secure, elastic and adaptive cloud computing basic network. So how should SDN switches be installed and configured?

1. Installation of SDN switch

In order to enable the SDN switch to achieve remote access to the external network, the installation location of the SDN switch should be comprehensively considered when using the SDN switch. When installing the SDN switch, not only should the IP address be configured, but also the port should be provided with external access so that the SDN switch can be installed.

2. SDN switch configuration

After installing the SDN switch in the system, when configuring the SDN switch, you should restart the system, then go to "Start/Programs" to select "SDN Switch Management" and run it, enter the location of the SDN switch according to the system requirements, and select Localhost. Finally, click the link, the system will enter the configuration interface under the command line, and you can complete the configuration of the SDN switch according to the prompts.

3. Configuration of virtual network card IP address

When using an SDN switch to achieve remote network access, the virtual network card software must be installed on each machine device that needs to be accessed. After the installation is complete, restart the system to enter the network configuration window for network configuration.

4. Establish a connection

After the communication configuration is completed in the system, the "EDOAS" icon will pop up in the "Connection Management" of the system. Double-click the icon to establish a connection between the current system and the SDN switch, and the connection status between the current system and the SDN switch will be displayed in the right window.

5. Enable remote machines to access internal network resources

If a remote machine wants to access internal resources, it should first establish a connection with the switch, and also complete the connection between the machine providing the service and the SDN switch. Then, enter the address to be accessed in the IE address of the remote machine, and the external network machine can access the internal network.

Computer networks are mainly connected through special equipment and communication media. They can be formed by connecting special equipment with multiple computers, or by connecting a single network with special equipment.