Design &Implementationof Software- DefinedNetwork & its components Shivam Verma School Of IT Illinois State University Email:[email protected] AbstractIn this paper, I have designed andimplemented the software-defined network with its components like programmingnodes, sensor nodes on data plane, controller etc. For network control, thecentralized controller node is configured and for transferring the packets, thesensor nodes are utilized.
Hence, the goal of this paper is to design andimplement SDN and its components. This paper also describes the SDNarchitecture in two ways. First is the high-level descriptive overview and thesecond describe the essentials of the architecture.
1.Introduction Because of highflexibility, Software-defined Networking (SDN) will be widely used in thefuture generation. SDN has been deployed in many companies like Google, Amazonetc. in their data center.
In SDN the data plane and the control plane aredecoupled, and switches are made free from complex routing computation and aremore concerned in forwarding the packets. In the traditional computer network,switches perform network routing with the help of built-in routing logicwhereas in Software-Defined Network (SDN) they don’t have such power 1. Insteadof this, the logic is extracted and forwarded to the SDN network controllerwhich in turn form the required programmable algorithm. 2.
Principlesand Architectural components The following defines the architecturalcomponents which are used in the defining the SDN. They are-· SDN Application (SDN App): SDN Applications are programs that are used to communicate with the control layer via SouthboundInterface. For the internal decision-making purposes, they may alsoabstract an abstracted view of the network. An SDN Application comprises of one SDN ApplicationLogic and at least one Northbound Interfaces (NBIs) drivers.· SDN Controller: The SDN Controller is a centralizedsystem which is responsible for translating all the requirements from the SDNApplication layer to all the SDN Data path, also provide the SDN Application (SDNApps) the abstract of the network, this view may also include all thestatistics and the events. SDNController consists of CDPI Driver, SDN Control Logic and at least one NorthboundInterfaces(NBI) Agents .· SDN Data path: Itis a network device in a Software-defined Network whose representation is asoftware based.
They are implemented in the devices like switches that areresponsible to move data packets on the network. They play a important role incommunicating with the control plane and the application plane layers. SDN Datapath consists of a CDPI agent and a set of one or more traffic sending enginesand activity handling functions. The functions and the traffic sending enginesmay also include simple sending of the data path’s external interfaces orinternal activity handling functions. One or more SDN Data paths may be definedin one single network elements or in multiple physical network elements.
· SDN Control to Data-PlaneInterface(CDPI): TheSDN Control to Data-Plane Interface can be defined as an interface between SDNController and an SDN Data path which support and gives control to all themoving forward operations, capabilities, reporting of statistics andnotification of events.· SDN Northbound Interfaces(NBI): The SDN Northbound Interfaces canbe defined as the interfaces between the SDN Applications and SDN Controllers.Other than this they also provide an abstract network views and provide thebest network decision and requirements. This type of abstraction can be foundat both level of latitude and longitude i.e. level of abstraction and differentlevels of functionality.
· Interface Drivers & Agents: A driver-agent pair is requiredfor the successful implementation of each interface. The agent represents thesouthside or the bottom of the network and the driver represent the northern orthe top side of the network.· Management & Admin: All the static tasks that occuroutside of the control, application and data planes are handled by themanagement plane. For example: Business relationship management, assignresources, equipment setup, configurations of various entities. Each businessentity has its own entities of management.
One of the limitation of this SDNArchitecture is the communication between different management entities. 3. SDNOVERVIEW Thissection describes the SDN architecture in two ways. 3.1is the high-level descriptive overview and 3.2 describe the essentials of thearchitecture. 3.
1 Descriptiveoverview Thepoint of SDN is to give open interfaces that empower the improvement ofprogramming that can control the availability gave by an arrangement of systemassets and the stream of system activity however them, alongside conceivableinvestigation and adjustment of movement that might be performed in the system.The four main pillars 23 of SDN include:• Separation of control and data planes• The network devices can be programmed through software applicationsand/or application programming interfaces (APIs)• Logical centralization of (possiblyphysically distributed) network control(e.g., routing logic, bandwidth assignment) logic to an SDNcontroller which has global view of data flow across network.
• Forwarding decisions are flow-based (streamof packets) rather than packet-based. Figure3.1 introduces the basic overview of Software-Defined Network.
The basic viewconsists of data plane, control plane ,and an application plane. The data planelayer or the infrastructural layer comprises of network elements or theforwarding devices, which interact with the control plane or control layerthrough a southbound interface from the controller which is also known as thecontrol-data plane interface 4. In theApplication layer, the SDN Applications exists which communicate to the networkrequirement through the controller with the help of the northbound interfaces,primarily known as NBIs. Then in the between of the data plane layer andapplication layer exists the control layer where the SDN Controller translatesthe network applications requirements and give relevant information to the SDNapplications (SDN Apps). The basic concept of the data plane in the SDNArchitecture comprises of the traffic forwarding and processing functions. Figure 3.1 Overviewof Software-Defined Networking Architecture 3.
2Concise statement of architectural essentials Figure 3.2 describes the majorcomponents and the interfaces of the SDN architecture. In this SDN Architecture,there is no physical realization of the components. Data Plane The data plane comprises of one or more network elements orthe forwarding devices and each of consist of traffic sending and all theresources required for the traffic processing. ControllerPlane The controller plane comprises of SDN Controller or networkcontroller which translatesthe network applications requirements and give relevant information to the SDNapplications (SDN Apps). Application Plane The application plane comprises of one or more applicationswhich have the control of resources which are given and exposed by the one ormore SDN Controllers.
Management The basic functionality of the manager is to give andprovide resources from the particular client in the lower plane to the cliententity in the higher plane. Administration Each entity in the north and south plane or layer belong tothe different administrative domain and it’s the duty of the manager to provideappropriate administration domain to a different entity. Figure 3.2 SDN Overview, with physical dataplane 4.OPENFLOW The OpenFlow is the standardinterface or the APIs used between the control plane and the dataplane(forwarding layers) of the SDN Architecture. An open flow protocol is astandardized protocol for interacting with the forwarding behaviors of switchesfrom multiple vendors. No other standard protocol can do what OpenFlow can do.The protocol is implemented on both the SDN Control software and also on thenetwork infrastructure devices.
OpenFlow identifies the network traffic basedon the pre-defined match rules that can be made or programmed by the SDNsoftware(controlled). According to the OpenFlow protocol, the SDN enabled switchhas to register all its status and configurations before it will be able toforward the packets in the network. During this registration process andconfiguration process, the SDN Controller builds a topology for the entirenetwork. 4.1 Benefits of OpenFlow-BasedSoftware-Defined Networks Few of the benefits are described below and they are 5: · Centralizedcontrol of multi-vendor environments: SDN control software can controlany OpenFlow enabled device from any vendor, they can use any SDN-basedmanagement oriented tools to quickly configure and update any devices in theentire network. · Reducedcomplexity through automation: OpenFlow based SDN gives a networkautomation and management framework which make it possible to automate all thetasks which are done manually today. This process of automation will reduce allthe operational overhead, decrease network instability which occurs due to theoperator error etc.
It will also increase business agility by using the SDN, cloud-basedapplications.· Higherrate of innovation: It offers various businessinnovation at real time to meet the business needs and user requirements. Byvirtualizing the network, it gives the ability to control the behavior of thenetwork and can introduce new services and control the network capabilities inonly few hours.· Increasednetwork reliability and security: OpenFlow based SDN provides IT todevelop high-level configuration which is then translated with the help of theOpenFlow protocol and policies. An OpenFlow-based SDN completely remove theneed for configuring the network devices each time, which help in reducing thechance of network failures due to the configurations.
· Moregranular network control: OpenFlow based SDN defines a flow-basedcontrol model which helps IT to apply policies at a very granular level. Thisflow-based control provides cloud operators to support multi-tendency even ifthey are controlling traffic, security etc.· Betteruser experience: By centralizing the whole networkand providing state information available to a higher-level application. Alsowith OpenFlow-based SDN, the video application will be able to detect thebandwidth which is available in the network in real time and automaticallychange and adjust the resolution with respect to the bandwidth.
5.ONGOING RESEARCH EFFORTS AND CHALLENGES Few of the challenges which are beenfaced are: 1. Switch DesignsThecurrently available OpenFlow switches are very diverse and pose differences interms of performance, control channel throughput, interpretation of particularprotocol and architecture.Implementationhas provided an impact on the accuracy and performance of switches. Oneapproach to fix this problem is to use NOSIX 6, it is an API that is used toseparate the application expectations from the switch. For doing this NOSIX hasa pipeline of various switch drivers and flow tables. 2.
ControllerPlatformsInSDN model controller is the most important pillar of the architecture. As aresult of this efforts are given to increase the performance of the SDNControllers and to make it more scalable, highly available and a programmer-friendlysoftware. 3. ResilienceTheresilience of SDN is a challenge due to the various possible failure present inthe different pieces of the SDN Architecture. Google B4 7 is one of theexamples that have provided evidence and proven that SDN can be resilience. 4. ScalabilityOneof the major concerns of SDN network is the Scalability.
The major scalabilityproblems are related to the decoupling of the control plane and data plane. Asa result, various scaling concerns protocol has been provided includingDevoFlow, DIFANE, Onix, HyperFlow etc. 6.CONCLUSION In this paper I haveexplained the SDN Architecture with two ways and how the implantation willimpact the network and how it is giving rise to the current research problemsand what all challenges are being faced or will be faced. Also, an API protocolknown as OpenFlow was also explained, how an OpenFlow based SDN is beneficial andhow it is impacting the IT world. 7. REFERENCES 1 D. Kreutz, F.
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