CS6250 Module 8 Practice Exam Guide
2026
1. 3 perspectives of 1. A plane-oriented view (management, control, data)
SDN Landscape
2. The SDN layers
3. A system design perspective
2. How many layers 8
in the SDN Layers
3. 1. Infrastructure SDN infrastructure consists of networking equipment (routers, switches and other
middlebox hardware). All they do is forward, and all logic to operate them is done
with SDN controller.
ex) Switch Light (OpenFlow switch)
4. 2. Southbound These are interfaces that act as connecting bridges between control and forward-
interfaces ing elements. Separate control and data plane.
ex) OpenFlow
5. 3. Network Virtu- the transformation of a network that was once hardware-dependent into a network
alization that is software-based
6. 4. Network Oper- SDNs goal is to ease network management by using a logically centralized con-
ating Systems troller: the network operating system (NOS). NOS provides abstractions, essential
services and common APIs to developers
7. 5. Northbound Northbound interfaces are supposed to be a mostly software based, as opposed
Interfaces to the Southbound interfaces.
8. 6. Lan- Use programming languages that support virtualization such as Pyretic
guage-based vir-
tualization
1/5
, CS6250 Module 8 Practice Exam Guide
2026
9. 7. Network pro- Network programmability can be achieved using low-level or high-level program-
gramming lan- ming languages.
guages
Using low-level languages, it is diflcult to write modular code, reuse it and it
generally leads to more error-prone development.
High level programming languages in SDNs make development more modular,
code more reusable in control plane, and allow faster development.
10. 8. Network appli- These are the functionalities that implement the control plane logic and translate
cations: to commands in the data plane. Apps such as routing, load balancing, security
enforcement,
11. OpenFlow Flow It is based on a pipeline of flow tables where each entry of a flow table has three
Tables parts:
a) a matching rule
b) actions to be executed on matching packets
c) counters that keep statistics of matching packets.
When a packet arrives, the lookup process starts in the first table and ends with
either a match in one of the tables of the pipeline or with a miss
12. What's the main The Southbound interfaces or APIs are the separating medium between the control
purpose of plane and data plane functionality.
southbound in-
terfaces?
13. What are 1. Event-based messages that are sent by forwarding devices to the controller
three informa- when there is a link or port change.
tion sources pro-
vided by Open- 2. Flow statistics are generated by forwarding devices and collected by the con-
Flow protocol? troller.
2/5
2026
1. 3 perspectives of 1. A plane-oriented view (management, control, data)
SDN Landscape
2. The SDN layers
3. A system design perspective
2. How many layers 8
in the SDN Layers
3. 1. Infrastructure SDN infrastructure consists of networking equipment (routers, switches and other
middlebox hardware). All they do is forward, and all logic to operate them is done
with SDN controller.
ex) Switch Light (OpenFlow switch)
4. 2. Southbound These are interfaces that act as connecting bridges between control and forward-
interfaces ing elements. Separate control and data plane.
ex) OpenFlow
5. 3. Network Virtu- the transformation of a network that was once hardware-dependent into a network
alization that is software-based
6. 4. Network Oper- SDNs goal is to ease network management by using a logically centralized con-
ating Systems troller: the network operating system (NOS). NOS provides abstractions, essential
services and common APIs to developers
7. 5. Northbound Northbound interfaces are supposed to be a mostly software based, as opposed
Interfaces to the Southbound interfaces.
8. 6. Lan- Use programming languages that support virtualization such as Pyretic
guage-based vir-
tualization
1/5
, CS6250 Module 8 Practice Exam Guide
2026
9. 7. Network pro- Network programmability can be achieved using low-level or high-level program-
gramming lan- ming languages.
guages
Using low-level languages, it is diflcult to write modular code, reuse it and it
generally leads to more error-prone development.
High level programming languages in SDNs make development more modular,
code more reusable in control plane, and allow faster development.
10. 8. Network appli- These are the functionalities that implement the control plane logic and translate
cations: to commands in the data plane. Apps such as routing, load balancing, security
enforcement,
11. OpenFlow Flow It is based on a pipeline of flow tables where each entry of a flow table has three
Tables parts:
a) a matching rule
b) actions to be executed on matching packets
c) counters that keep statistics of matching packets.
When a packet arrives, the lookup process starts in the first table and ends with
either a match in one of the tables of the pipeline or with a miss
12. What's the main The Southbound interfaces or APIs are the separating medium between the control
purpose of plane and data plane functionality.
southbound in-
terfaces?
13. What are 1. Event-based messages that are sent by forwarding devices to the controller
three informa- when there is a link or port change.
tion sources pro-
vided by Open- 2. Flow statistics are generated by forwarding devices and collected by the con-
Flow protocol? troller.
2/5
