CS 6250 Exam 2 A Comprehensive Set Of Questions
And Answers (Verified Answers) Latest Version
Update 2026.
What are 2 reasons computer networks are complex and difficult to
manage that led to the development of SDN? - ANSWER: 1. Diversity of
network equipment
2. Proprietary technology required for equipment
Why would equipment diversity cause complexity when managing a
network? - ANSWER: Different software must be used for different
protocols (7)
Why do proprietary technologies cause complexity when managing
networks? - ANSWER: Some equipment (router, switch, etc.) run on
closed/proprietary software
Configuration interfaces vary as a result.
This causes issues for managing devices centrally. (7)
What is the simple idea of SDN that helps make networks more
manageable? - ANSWER: Separate tasks into control plane and data
plane. (7)
What are the 3 phases of history of SDN? - ANSWER: 1. Active
networks
1|Page
,2. control plane and data plane separation
3. OpenFlow API and network operating systems (7)
What led to the growth of active networks, and what is their goal? -
ANSWER: 1. the tediousness of standardizing new protocols
2. goal is to open up network control with an API that exposes resources
and supports *customization of functionalities* for subsets of packets
passing through network nodes
(7)
Why do active networks conflict with idea of E2E? - ANSWER: They
require customization at network nodes (not simplicity at network core)
(7)
What were the two types of programming models in active networking?
How are thy different? - ANSWER: 1. Capsule model
- carries in band data packets
- most used in relation to active networking
- code distribution ACROSS networks
- data plane
2. Programmable router/switch model
- out of band mechanisms
- decision-making a job for the NETWORK OPERATOR
- Difference is where the code to execute at the nodes was carried (7)
2|Page
,What are 4 tech developments that encouraged active networking? -
ANSWER: 1. reduction in computation cost (more processing can take
place in the network)
2. advancement in programming languages
3. advancement in rapid code compilation and formal methods
4. funding agencies promoted interoperability among projects
- necessary because there were no short-term use cases
(7)
What are 4 problems that encouraged active networking? - ANSWER: 1.
developing network services took a long time
2. third party interests to dynamically meeting needs of app and network
conditions
3. researches needed a network for large-scale experiments
4. disadvantage of diverse models and vendors meant a desire for
unified control over middleboxes (7)
What are 3 contributions of SDN? - ANSWER: 1. programmable
functions in network = lower barrier to innovation
2. network virtualization and ability to demultiplex based on packet
headers
3|Page
, 3. vision of unified architecture for middlebox orchestration
(7)
Which plane are active networks associated with? - ANSWER: Data
plane (7)
What plane do programmable functions in active networks focus on
increasing programmability, and why? - ANSWER: - Data plane
- isolate experimental traffic from normal traffic (7)
What were some downfalls of active networking? - ANSWER: - it was
too ambitions
- didn't emphasize performance and security
- it didn't solve any short term problems
- end users need to be ale to write in java (7)
Did active network do anything for performance? Security? - ANSWER:
No (7)
What challenge did control and data plane separation tackle? -
ANSWER: Challenging how existing routers and switches tightly
integrated the data and control plane (7)
What were 4 tech developments that paved the way for control and data
plane separation? - ANSWER: 1. packet forwarding (data plane) was
implemented in hardware (separate from control plane)
4|Page
And Answers (Verified Answers) Latest Version
Update 2026.
What are 2 reasons computer networks are complex and difficult to
manage that led to the development of SDN? - ANSWER: 1. Diversity of
network equipment
2. Proprietary technology required for equipment
Why would equipment diversity cause complexity when managing a
network? - ANSWER: Different software must be used for different
protocols (7)
Why do proprietary technologies cause complexity when managing
networks? - ANSWER: Some equipment (router, switch, etc.) run on
closed/proprietary software
Configuration interfaces vary as a result.
This causes issues for managing devices centrally. (7)
What is the simple idea of SDN that helps make networks more
manageable? - ANSWER: Separate tasks into control plane and data
plane. (7)
What are the 3 phases of history of SDN? - ANSWER: 1. Active
networks
1|Page
,2. control plane and data plane separation
3. OpenFlow API and network operating systems (7)
What led to the growth of active networks, and what is their goal? -
ANSWER: 1. the tediousness of standardizing new protocols
2. goal is to open up network control with an API that exposes resources
and supports *customization of functionalities* for subsets of packets
passing through network nodes
(7)
Why do active networks conflict with idea of E2E? - ANSWER: They
require customization at network nodes (not simplicity at network core)
(7)
What were the two types of programming models in active networking?
How are thy different? - ANSWER: 1. Capsule model
- carries in band data packets
- most used in relation to active networking
- code distribution ACROSS networks
- data plane
2. Programmable router/switch model
- out of band mechanisms
- decision-making a job for the NETWORK OPERATOR
- Difference is where the code to execute at the nodes was carried (7)
2|Page
,What are 4 tech developments that encouraged active networking? -
ANSWER: 1. reduction in computation cost (more processing can take
place in the network)
2. advancement in programming languages
3. advancement in rapid code compilation and formal methods
4. funding agencies promoted interoperability among projects
- necessary because there were no short-term use cases
(7)
What are 4 problems that encouraged active networking? - ANSWER: 1.
developing network services took a long time
2. third party interests to dynamically meeting needs of app and network
conditions
3. researches needed a network for large-scale experiments
4. disadvantage of diverse models and vendors meant a desire for
unified control over middleboxes (7)
What are 3 contributions of SDN? - ANSWER: 1. programmable
functions in network = lower barrier to innovation
2. network virtualization and ability to demultiplex based on packet
headers
3|Page
, 3. vision of unified architecture for middlebox orchestration
(7)
Which plane are active networks associated with? - ANSWER: Data
plane (7)
What plane do programmable functions in active networks focus on
increasing programmability, and why? - ANSWER: - Data plane
- isolate experimental traffic from normal traffic (7)
What were some downfalls of active networking? - ANSWER: - it was
too ambitions
- didn't emphasize performance and security
- it didn't solve any short term problems
- end users need to be ale to write in java (7)
Did active network do anything for performance? Security? - ANSWER:
No (7)
What challenge did control and data plane separation tackle? -
ANSWER: Challenging how existing routers and switches tightly
integrated the data and control plane (7)
What were 4 tech developments that paved the way for control and data
plane separation? - ANSWER: 1. packet forwarding (data plane) was
implemented in hardware (separate from control plane)
4|Page
