EXAM 2 CS6250 COMPUTER NETWORK (ACTUAL 2025/2026)
LATEST CERTIFIED QUESTIONS AND VERIFIED ANSWERS
GRADED A+
Four defining features in an SDN architecture? - -----
Answers-----1) Flow-based fowarding: the rules for
forwarding can be computed based on any number of header
field values
2) separation of data plane an control plane: the switches
operate on the dat aplane and they only execute rules defined
in the flow tables.
3) Network control functions
4) a programmable network: network-control applications act
as the brain of SDN control plane by managing the network
What are the three layers of SDN controller? - -----Answers-
----communication layer: communicating between the
controller and the network elements
network-wide state-management layer: stores the information
of network-state
interface to the network-control application layer:
communicating between controller and applications
,Three perspectives of SDN and what they do - -----Answers--
---data plane: functions and processes that forward data in
the form of packets or frames
control plane: functions and processes that determine which
path to use using protocols and forwarding tables
management plane: services that are used to monitor and
configure the control functionality
advantages of SDN - -----Answers-----1. Shared abstractions
2. Consistency of same network information
3. Locality of functionality placement
4. Simpler integration
What is the main purpose of southbound interfaces? - -----
Answers-----Separating medium between the control plane
and data plane functionality
What are three information sources provided by OpenFlow
protocol? - -----Answers-----1. Event-based messages that
are snet by forward devices to controller when there is a link
or port change
2. flow statistics are generated by forwarding devices and
collected by controller
, 3. Packet messages are sent by forwarding devices to
controller when they do not know what to do with a new
incoming flow
What are the core functions of the SDN controller? - -----
Answers-----Network service functions such as topology,
statistics, notifications, device management, shortest path
forwarding and security mechanisms
What are the differences between centralized and distributed
architectures of SDN controllers? - -----Answers-----Single
entity manages all devices in the network
In the distributed version, its a centralized cluster of nodes or
physical set of elements
When would you want a distributed controller over a
centralized one? - -----Answers-----If you want to scale your
network and want better fault tolerance
Describe the purpose of each component of ONOS in a SDN
control platform - -----Answers-----Serves as the master
openflow controller for a group of switches
??? weird question
How does ONOS achieve fault tolerance? - -----Answers-----
ONOS redistributes the work of a failed instance to other
LATEST CERTIFIED QUESTIONS AND VERIFIED ANSWERS
GRADED A+
Four defining features in an SDN architecture? - -----
Answers-----1) Flow-based fowarding: the rules for
forwarding can be computed based on any number of header
field values
2) separation of data plane an control plane: the switches
operate on the dat aplane and they only execute rules defined
in the flow tables.
3) Network control functions
4) a programmable network: network-control applications act
as the brain of SDN control plane by managing the network
What are the three layers of SDN controller? - -----Answers-
----communication layer: communicating between the
controller and the network elements
network-wide state-management layer: stores the information
of network-state
interface to the network-control application layer:
communicating between controller and applications
,Three perspectives of SDN and what they do - -----Answers--
---data plane: functions and processes that forward data in
the form of packets or frames
control plane: functions and processes that determine which
path to use using protocols and forwarding tables
management plane: services that are used to monitor and
configure the control functionality
advantages of SDN - -----Answers-----1. Shared abstractions
2. Consistency of same network information
3. Locality of functionality placement
4. Simpler integration
What is the main purpose of southbound interfaces? - -----
Answers-----Separating medium between the control plane
and data plane functionality
What are three information sources provided by OpenFlow
protocol? - -----Answers-----1. Event-based messages that
are snet by forward devices to controller when there is a link
or port change
2. flow statistics are generated by forwarding devices and
collected by controller
, 3. Packet messages are sent by forwarding devices to
controller when they do not know what to do with a new
incoming flow
What are the core functions of the SDN controller? - -----
Answers-----Network service functions such as topology,
statistics, notifications, device management, shortest path
forwarding and security mechanisms
What are the differences between centralized and distributed
architectures of SDN controllers? - -----Answers-----Single
entity manages all devices in the network
In the distributed version, its a centralized cluster of nodes or
physical set of elements
When would you want a distributed controller over a
centralized one? - -----Answers-----If you want to scale your
network and want better fault tolerance
Describe the purpose of each component of ONOS in a SDN
control platform - -----Answers-----Serves as the master
openflow controller for a group of switches
??? weird question
How does ONOS achieve fault tolerance? - -----Answers-----
ONOS redistributes the work of a failed instance to other
