Software-defined Web learning Summary

Software defined network sdn QoS Span style= "font-family: ' founder of the Body simplified '; Optimization and configuration of network properties to improve network utilization and security; The control layer is responsible for the abstraction of the data plane, the maintenance of the network topology and state information, the control and invocation of the forwarding surface resource according to the requirements of the application Layer service, which is also called the network operating system ( network Operating System ) layer, the infrastructure layer is also called the data forwarding layer, which is based on the business flow table to achieve data forwarding and processing. The control layer exposes the programming interface to the application layer by providing a north-to-the interface, through such as OpenFlow

describe the SDN The architecture:

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The Intelligent Network is made up of software-based SDN The controller is centrally provided, which controls the network in a global perspective, and based on this architecture, the network device is a single logical exchange entity from the point of view of the network application and policy engine. Operating enterprises from a single logical management point of operator Independent network control, which greatly simplifies the design and operation of the network. SDN also greatly simplifies the network device itself, because it no longer requires the understanding and handling of thousands of protocol standards, but only the forwarding of data domains according to the instructions of the SDN Controller.

SDN The controller completes the centralized control of network intelligence, network manager can change the behavior of network in real time and complete the deployment of new applications and services in a few hours or days. It doesn't take weeks or months to complete a business deployment, as it did in the past. Through the control layer centralized management, sdn

architecture provides a range of application programming interfaces (

in summary terms, SDN The architecture simplifies network control through virtual abstraction techniques like computer domain, and provides simple configuration and management for upper applications by shielding complex network layers. SDN Technology realizes the abstraction of distributed state by separating the network control and forwarding functions, and implementing the global view to shield the distributed state information from the bottom layer and provide the whole network views. It facilitates application and business innovation by providing a specific view abstraction on the basis of the global view to simplify the operation of the upper-level business application for the underlying network.

the processing protocol for data forwarding plane and control plane isOpenFlow. OpenFlowIt's from Stanford University.Nick McKeownThe original aim of the professor was to deploy a new network protocol in the existing campus network, and nowOpenFlowhas been used asSDNthe Control Data plane interface (South interface) in the architecture is widely accepted. ONFthe establishment isOpenFlowmilestones in the history, which markedOpenFlowformally towards the road of industrialization Development,ONFis working to focus onOpenFlowAgreement ImplementationSDNStandards and specifications. CurrentlyOpenFlowMultiple versions have been published, butONFare continuing toOpenFlowThe agreement was perfected so thatOpenFlowBecome a stable commercial deployment standard.

OpenFlow the network control function is decoupled from the data forwarding function, the controller is separated from the network equipment, and the controller is responsible for the realization of the control logic and the generation, maintenance, configuration and distribution of the flow table. OpenFlow The switch, as a network device, is only responsible for the data forwarding according to the flow table items and does not need to care about the upper logic, in this way, the network can flexibly dynamic logical control and high-level policy configuration, and OpenFlow The flow table structure makes the processing granularity of data surface refinement, and realizes the flat network processing level.

Openflow by the controller and OpenFlow The switch consists of two parts, which are related to each other as shown:

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network operating system in the controllerNOScomplete the implementation of the control logic, the basic information of the network isNOSmaintained in the form of a network view,NOSThe various applications running on the network view are completed by calling theOpenFlowThe operation of the switch, in order to achieve the purpose of the control network. Current multipleNOSsystem has been released, such as based onC++/pythonfor the development ofNOX, based onJavalanguage for the development ofBeaconand so on.

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OpenFlow The switch is responsible for data-plane forwarding, which includes at least flow tables, secure channels, and OpenFlow three parts of the agreement. The flow table consists of a behavior (action) associated with each flow table entry, which instructs the switch to handle the convection, and the secure channel connects the switch and the remote controller, which allows the controller and the switch to pass through the The OpenFlow protocol is exchanged for commands and groupings. when the traffic arrives at the OpenFlow switch, the stream will match according to the order of the flow table, and according to the situation, such as the storage and forwarding of the line speed, the encapsulation after the transfer to the controller or discard operations.

OpenFlowThe channel is the interface of the switch connection controller for switching between the controller and the switchOpenFlowmessage. All messages must followOpenFlowThe format specified in the protocol is encapsulated and transmitted between the Controller and the switch. Through this channel, the controller can configure, manage the switch, receive event information of the switch, and instruct the switch how to handle the user packet. OpenFlowthe channel is established in the Secure Transport Layer protocol (TLS) or no protectionTCPconnection. A typical controller can be connected to a number of different switches, corresponding to a number of differentOpenFlowChannel. On the other hand, the switch can connect to one controller or multiple controllers to ensure reliability. The switch initiates a connection to the controller that can be built on a single network, such as a separate private network, or a network managed by that switch, in which case the in-band controller connection, the only requirement is that the network must be able to establishTCP/IPconnection. In addition, for the sake of parallelism,OpenFlowchannels can also be composed of multiple network connections.

The future network of technology implementation must be virtualized at the same time ( 2012 year ten month, by T IT

Network function Virtualization is designed to transform traditional network architectures by using standard IT Virtualization technology to install many network devices as software in a high-performance server, switch, and storage hardware that meets industry standards. , hardware devices in data centers, network nodes, and end users only need to provide a unified standardized interface, and traditional network applications will be installed directly on top of high-performance hardware for business deployment.

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Network function Virtualization will bring many benefits to the operators and the network itself, which greatly reduces the cost of network equipment and the energy consumption during operation, saves the cost of deploying the application, reduces the cycle of new business deployment, accelerates the speed of network innovation, So that network operators can quickly adapt to market demand for business adjustment, through NFV, network operators can share the underlying network resources to multiple tenants, to provide user-oriented target services;NFV The opening of the network itself opens the door to the virtual application market for pure software companies, while providing network operation access to small companies and academia under the premise of guaranteeing network security, which will greatly promote the innovation and development of new business and new network economy.

NFVdifferent from traditional hardware network application, it realizes the decoupling of network function and hardware through the standard execution environment and management interface, which makes many virtual network functions share the underlying hardware in the form of virtual machine. NFVimplementation also faces many challenges and technical challenges, the first must define a unified interface to achieve portability and interoperability, only the implementation of the standard interface to the network function in the form of software deployment, second, the network for latency and performance requirements are high, inNFVenvironment, all the network functions will be implemented in the form of software, how to ensure the allocation of the underlying hardware resources to provide the same performance as the hardware will be the focus of the problem to solve;NFVto deploy on a large scale, you must rely on comprehensive and efficient network management,NFVmakes the network more flexible also makes the network management difficulty increase;SDNThe basic requirements of the same,NFValso must ensure that the virtual machine between the isolation and security requirements, because the network function application and the management of the software occur on the same physical machine, how error-free and non-disruptive to the individual virtual machine control and management is also inNFVthe difficult problem that must be solved effectively when the whole network is deployed.

NFV with the SDN is a mutually reinforcing relationship, the two are not interdependent but highly complementary, and they can be implemented independently of each other, but through SDN between control and data plane, the performance of network function virtualization can be greatly improved, simplifying the deployment difficulty and operation of virtualization implementation. NFV provides an environment for the operation of SDN software, which can be said that NFV and SDN Combined networking will bring the greatest degree of virtualization capability.

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Software-defined Web learning Summary