Module 7: Practice Quiz

Question 1

The main reason why SDNs were created was because of the increase of internet users.

T/F

Answer 1

False

The creation of SDNs was driven by the need for better network management and innovation, not just the increase in users.

Question 2

SDNs divide the network in two planes: control plane and data plane, to ease management and speed up innovation.

T/F

Answer 2

True

This division allows for more efficient network management and facilitates innovation.

Question 3

The Active Networks phase consisted mainly of creating a programming interface that exposed resources/network nodes.

T/F

Answer 3

True

This phase supported customization of functionalities for subsets of packets passing through the network.

Question 4

The ‘Active Network’ phase focused on device-level configurations, and the ‘Separation of the Control and Data Plane’ phase focused on network-wide visibility.

T/F

Answer 4

True

The focus of these phases was different, with the latter emphasizing the separation of functions for better management.

Question 5

An OpenFlow switch has a table of packet-handling rules, and whenever it receives a packet, it determines the highestpriority matching rule, performs the action associated with it and incrementstherespective counter.

True/False

Answer 5

True

Question 6

One of the downfalls of OpenFlow when it was first created was that it was hard to deploy and scale it easily.

T/F

Answer 6

False

Initial deployment challenges hindered its widespread adoption.

Question 7

SDNs use (software/hardware) to control the routers’ behavior (e.g., the path selection process).

Answer 7

software

Question 8

With the separation of the control plane and the data plane, any change to the forwarding functions on a router is independent from the routing functions of the control plane.

T/F

Answer 8

True

This independence allows for more flexible network management.

Question 9

In the SDN approach, the controller that computes and distributes the forwarding tables to be used by the routers is:
- Physically separate from the routers
- Located within each router

Answer 9

Physically separate from the routers

This separation enhances network management and control.

Question 10

Software implementations in SDN controllers are increasingly open and publicly available, which _______ innovation in the field.

Answer 10

speeds up

Open access to software fosters collaboration and rapid development.

Question 11

The network-control applications use the information about the network devices and elements, provided by the controller, to monitor and control the network devices.

T/F

Answer 11

True

Question 12

In an SDN, the controller is responsible for the ——- of the traffic, and the SDN-controlled network elements such as the switches are responsible for the ——— the traffic.

Answer 12

routing,forwarding

Question 13

Traffic forwarding can be based on any number of header field values in various layers like the transport-layer, network-layer and link-layer.

T/F

Answer 13

True

This flexibility allows for more granular control over traffic management.

Question 14

SDN controllers operate on the ———— plane.

Answer 14

Control

Question 15

Match the number of the missing components in the following image with their respective name/example:

Answer 15

1. Load Balancer
2. RESTful API
3. Flow Tables
4. OpenFlow
5. SDN Controller

Question 16

The northbound interface is used by the controller and the network-control applications to interact with each other.

T/F

Answer 16

True

This interface facilitates communication between different layers of the SDN architecture.

Question 17

A REST interface is an example of a southbound API.

T/F

Answer 17

False

REST interfaces are typically considered northbound APIs as they facilitate communication with applications.

Question 18

SDN controllers that are implemented by centralized servers are more likely to achieve fault tolerance, high availability and efficiency.

T/F

Answer 18

True

Centralized implementations can streamline management and enhance reliability.