Top 25 SDN Interview Questions And Answers For Experienced 2019. If you are looking for interview questions on SDN with answers, then you are at right place. Here codingcompiler sharing a list of 27 real-time Software Defined Network interview questions. These interview questions for network consultants will help to crack your next SDN job interview. Happy learning and all the best for your future.
SDN Interview Questions
- What is Software Defined Network (SDN)?
- What are Control Plane (CP) and Data Plane (DP) in SDN?
- How SDN is different from a normal network setup?
- What are the advantages of SDN?
- What is Network Controller in SDN?
What are the central tasks of the Control Plane with its Network Controller?
What are the central tasks of the Data Plane with the forwarding hardware?
What is the advantage of central intelligence over distributed intelligence in SDN?
- What is data plane and what does it contain?
- How does control plane and data place communicate in SDN?
SDN Interview Questions And Answers
1) What is Software Defined Network (SDN)?
A) SDN stands for Software Defined Networking and it describes a process in which hardware and software are decoupled from each other. This offers many advantages, especially in complex networks it separates software and hardware in a network. .
The Software Defined Networking (SDN) goes back to a developed at Stanford University in 2005 concept. Since 2013, there are devices that can implement SDN. Put simply, hardware and software are decoupled.
2) What are Control Plane (CP) and Data Plane (DP) in SDN?
A) With the SDN, a central intelligence controls the data forwarding. This network controller is called Control Plane (CP). The hardware that actually makes the forwarding on command of the CP is the Data Plane (DP).
3) How SDN is different from a normal network setup?
A) Conventional networks use routers and switches. It is hardware that has its own intelligence (software). This means that every single device has to analyze, process and forward an incoming data packet. This leads to significant problems, especially in complex networks that rely on virtualization, for example. The hardware devices have different software levels or even different operating systems , making adjustments to a mammoth task. Software Defined Networking eliminates this problem because only the CP needs to be adapted.
4) What are the advantages of SDN?
A) The advantages of the SDN compared to conventional network structures are not limited to the simpler adaptation. In fact, Software Defined Networking also offers some benefits that are of interest even for home networking:
Conversions in the network succeed much faster, because much less manual work is necessary. The CP allows adjustment changes in the DP that would otherwise have to be done manually.
The hardware for SDN structures is much cheaper, because the DP does not need its own intelligence, but only with a rudimentary firmware must be equipped.
Wild growth or impractical isolated solutions regarding security configurations are excluded.
Overall, the network is much less susceptible to external attacks by SDN.
5) What is Network Controller in SDN?
A) The Network Controller is typically centralized and can control and manage a variety of network components such as routers or switches . The network operating system processes and stores all the information needed for control and management.
6) What are the central tasks of the Control Plane with its Network Controller?
A) The central tasks of the Control Plane with its Network Controller are the following:
- The management of the different network components
- The configuration of the hardware
- The configuration of network security relevant security specifications
- The management of access to the network components
- The control of data forwarding by the hardware
Creating the routing specifications for forwarding the data packets to the desired destination
7) What are the central tasks of the Data Plane with the forwarding hardware?
A) The central tasks of the Data Plane with the Forwarding Hardware are:
The forwarding of data packets
The receipt of control information from the Network Controller
8) What is the advantage of central intelligence over distributed intelligence in SDN?
A) Software defined networking moves away from the concept of distributed intelligence and the use of different operating systems. In the SDN, the intelligence of the network is moved to a central instance and the configuration of individual devices or operating systems is superfluous.
The goal of the concept is to reduce network maintenance and administration while increasing intelligence and flexibility. In addition, the hardware can concentrate on its actual task, the data forwarding, and is relieved of control and management functions.
9) What is data plane and what does it contain?
A) The Data Plane contains the hardware components that are responsible for the actual forwarding of the data packets. The devices work on Layer 3 or Layer 2 and perform the tasks of routers or switches at the data level. Your instructions and information can be obtained from the Control Plane.
10) How does control plane and data place communicate in SDN?
A) Depending on the implementation, the devices of the Control Plane and the Data Plane communicate via an open, standardized or manufacturer-specific protocol.
11) What is OpenFlow?
A) OpenFlow is one of the most well-known and widely used protocols for communication between Data Plane and Control Plane in an SDN is OpenFlow. It is a standardized communication interface between the control and forwarding levels and allows direct access to the forwarding functions of switches or routers. Access can be both direct and virtualized.
12) What is RBAC?
A) Administrative access to the control plane is handled by the protocols, such as the Role Based Access Control Protocol (RBAC). It offers a high safety standard and works based on roles.
13) What are the importance interfaces in the SDN?
A) In the SDN environment, the terms Northbound and Southbound interface are often used. The southbound interface communicates down with deeper layers of the network and the northbound up interface with higher levels.
14) What is Southbound interface in Software Defined Network?
A) In a software-defined network, the southbound interface ensures communication between the control plane and the data plane using a protocol such as OpenFlow. The network controller thus controls the forwarding of packets through the hardware via the southbound interface.
15) What is Northbound Interface in SDN?
A) The northbound interface in the SDN is directed upwards by the controller and communicates with higher level applications or management and control programs. Among other things, the automation and orchestration of the system takes place via the Northbound interface.
16) NFV vs SDN – What is the difference between NFV and SDN?
A) NFV and SDN – When it comes to network virtualization, most people think of software-defined networking (SDN). NFV and SDN are separate. Both technologies are designed to increase flexibility, reduce costs, support scalability, and accelerate the introduction of new services. But you can run one of them separately.
However, NFV and SDN are complementary, and SDN makes NFV applications simpler and more efficient, providing flexibility and streamlining operations by improving performance. In particular, using SDN to support NFV can help traffic steering (unloading, bypassing, selecting, etc.), dynamically expanding and shrinking, multi-tenancy, and load balancing.
SDN can help NFV accomplish tasks such as policy-managed forwarding and dynamic service provisioning. Conversely, the need for SDN can also be increased by using dynamic virtual overlays and multi-tenant NFVs.
16) Explain the concept of decoupling in SDN?
A) Typical network components such as switches consist of several parts. The data plane is responsible for delivering packets from one switch port to another. The management capabilities, on the other hand, are provided by the control plane. SDN is based on the idea of separating the two components – data and control plane – as switches still deliver packets from one port to another, but the control plane and all the functionality it belongs to is separate from the network hardware. To reach the goal, virtually all current solutions on the market divide the network into two layers: the underlay and the overlay.
17) What is Open vSwitch?
A) Open vSwitch is an open-flow implementation of OpenFlow that enables the operation of a control plane on a normal server.
18) How OpenStack handles SDN?
A) In almost all scenarios, there are at least two types of server types in an OpenStack cloud: controller nodes operate all services that are relevant to OpenStack itself, and hypervisor nodes host the VMs that customers launch via API or Web interface. In addition, in Openstack takes care of a separate service to the topic of SDN. This is called neutron and consists of many components.
19) What is Neutron API in OpenStack?
A) The Neutron API contains the entire configuration and serves as a focal point for clients who want to change the SDN configuration. It runs on the controller node. On all servers, the default setup uses the Layer 2 Agent for Open vSwitch. This sets up the local virtual switches based on the configuration in the API on each host so that virtual machines can dock there. It also ensures that the GRE or VXLAN connection between all hosts works.
20) How Network Function Virtualisation (NFV) is different from SDN?
A) NFV is the replacement of dedicated hardware with software solutions. For example, a physical load balancer can be replaced by a load balancer (Virtual Load Balancer) software running on its own virtual machine or on a dedicated server . Depending on the viewing angle, NFV can be seen as part of SDN or as an addition to SDN.
21) What is Orchestration in SDN?
A) Under the orchestration in a software defined network is defined as the central configuration of entire data centers to cloud service provider infrastructures, including the configuration of virtualized compute environments, virtual machines (VMs), storage solutions and the network.
22) What is Flow Management or Programmatic Control in SDN?
A) Flow management or “programmatic control” is the central management of individual data packet flows. This subset of SDN is often viewed as the central theme of SDN.
23) Wht is ONF?
A) The Open Networking Foundation (ONF) has defined the OpenFlow standard, which defines direct access to the forwarding plane of a switch or router, whether physical or virtual. This allows the forwarding and control plans of a network node to be separated.
24) What are the different approaches in flow management?
A) There are two different approaches to flow management:
1) Node-based flow management approach
2) Overlay approach
25) What is Node-based flow management approach in SDN?
A) In the Node-based flow management approach , the individual network nodes are controlled individually via a central controller using the OpenFlow standard. This is the preferred approach for new implementations.
26) What is Overlay approach in SDN?
A) In the overlay approach , for example “VxLAN”, individual data streams are tunneled through standard IP networks throughout. This eliminates the need for the entire network to be OpenFlow compliant. In each case only the corresponding tunnels have to be initiated. This is the preferred approach for implementations in existing network environments.
27) What is Ethernet Fabric?
A) The goal of the Ethernet Fabric is to build a highly flexible, cloud-ready and resilient data center network. The interaction of an Ethernet fabric and a software-defined network as described above can optimize the performance of networks to meet the fast-growing needs of the cloud age.
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