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CS6250 COMPUTER NETWORK EXAM 2 2025
QUESTIONS AND ANSWERS
What are 2 reasons computer networks are complex and difficult to manage
that led to the development of SDN? - correct answer - 1. Diversity of network
equipment
2. Proprietary technology required for equipment
Why would equipment diversity cause complexity when managing a network? -
correct answer - Different software must be used for different protocols (7)
Why do proprietary technologies cause complexity when managing networks? -
correct 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)
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What is the simple idea of SDN that helps make networks more manageable? -
correct answer - Separate tasks into control plane and data plane. (7)
What are the 3 phases of history of SDN? - correct answer - 1. Active networks
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? - correct
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? - correct answer - They
require customization at network nodes (not simplicity at network core)
(7)
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What were the two types of programming models in active networking? How are
they different? - correct 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)
What are 4 tech developments that encouraged active networking? - correct
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)
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What are 4 problems that encouraged active networking? - correct 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? - correct answer - 1. programmable
functions in network = lower barrier to innovation
2. network virtualization and ability to demultiplex based on packet headers
3. vision of unified architecture for middlebox orchestration
(7)
Which plane are active networks associated with? - correct answer - Data
plane (7)
CS6250 COMPUTER NETWORK EXAM 2 2025
QUESTIONS AND ANSWERS
What are 2 reasons computer networks are complex and difficult to manage
that led to the development of SDN? - correct answer - 1. Diversity of network
equipment
2. Proprietary technology required for equipment
Why would equipment diversity cause complexity when managing a network? -
correct answer - Different software must be used for different protocols (7)
Why do proprietary technologies cause complexity when managing networks? -
correct 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)
, Page | 2
What is the simple idea of SDN that helps make networks more manageable? -
correct answer - Separate tasks into control plane and data plane. (7)
What are the 3 phases of history of SDN? - correct answer - 1. Active networks
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? - correct
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? - correct answer - They
require customization at network nodes (not simplicity at network core)
(7)
, Page | 3
What were the two types of programming models in active networking? How are
they different? - correct 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)
What are 4 tech developments that encouraged active networking? - correct
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)
, Page | 4
What are 4 problems that encouraged active networking? - correct 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? - correct answer - 1. programmable
functions in network = lower barrier to innovation
2. network virtualization and ability to demultiplex based on packet headers
3. vision of unified architecture for middlebox orchestration
(7)
Which plane are active networks associated with? - correct answer - Data
plane (7)
