CS6250 COMPUTER NETWORK EXAM 2
(2026 Edition) | Full Practice Questions
with Confirmed Answers | 100% Accurate |
Graded A+
• L7: What are the three phases in the history of SDN? -✓✓1. Active
networks
2. Control and data plane separation
3. OpenFlow API and network operating systems
• L7: Summarize each phase in the history of SDN. -✓✓1. Active
networks
2. Control and data plane separation
3. OpenFlow API and network operating systems
Active networks
> Researchers wanted to test new ideas to improve network services.
This required standardization of new protocols by the IETF which was a
slow/frustrating process.
> More active networks which wanted to open up network control.
> Community belief: simplicity of the network core was vital to internet
success.
The pushes that encouraged active networking:
,> Reduction in computation cost
> PL Advancement (like java)
> Advances in rapid code compilation and formal methods.
Active networking envisioned unified control that could replace
individually managing these boxes.
Active networks made three major contributions related to SDN:
> Programmable functions in the network to lower the barrier of
innovation
> Introduced the idea of using programmable networks to overcome the
slow speed of innovation in networking.
Active networking produced a framework that described a platform that
would support experimentation with different programming models.
This led to network visualization.
Active networking was more involved in redesigning the architecture of
networks, so not as much emphasis was given to performance and
security. Since there were no specific short-term problems that active
networks solved, it was harder to see widespread deployment.
The next efforts had a more focused scope and distinguished between
control and data planes. This difference made it easier to focus on
innovation in a specific plane and inflict widespread change.
,Control and data plane separation
> Network operators were looking for better network-management
functions such as control over paths to deliver traffic.
> Identified that the challenge in network management depended on the
way existing routers and switches tightly int
• Expanded History -✓✓Active networks
Intro
Slow and frustrating process to standardize protocols fostered the push
for active networks trying to open up network control
Active networks with their network API went against the concept of
keeping the core simple
2 types of programming models in active networking:
Capsule model - carried in-band in data packets
Programmable router/switch model - established by out-of-band
mechanisms
Technology push - The pushes that encouraged active networking were:
Reduction in computation cost (more processing into the network).
Advancement in programming languages. (Java: platform portability,
code execution safety, and VM (virtual machine) technology to protect
the active node in case of misbehaving programs).
Advances in rapid code compilation and formal methods.
Funding from agencies such as DARPA (U.S. Defense Advanced
Research Projects Agency) for a collection promoted interoperability
among projects. There were no short-term use cases.
Use pull - The use pulls for active networking were:
, Network service provider frustration concerning the long timeline to
develop and deploy new network services.
Third party interests to add value by implementing control at a more
individualistic nature. This meant dynamically meeting the needs of
specific applications or network conditions.
Researchers' interest in having a network that would support large-scale
experimentation.
Unified control over middleboxes. Active networking envisioned unified
control that could replace individually managing these boxes.
Active networks contributions related to SDN:
Programmable functions in the network to lower the barrier to
innovation.
While many early visions for SDN concentrated on increasing
programmability of the control-plane, active networks focused on the
programmability of the data-plane.
The concept of isolating expe
• L7: What is the function of the control and data planes? -✓✓Control
plane - controls forwarding behavior of routers, such as routing
protocols and network middlebox configurations.
Data plane - performs actual forwarding as dictated by the control plane.
IP forwarding and layer 2 switching are functions of the data plane.
• L7: Why separate the control from the data plane? -✓✓The reasons we
separate the two are:
(2026 Edition) | Full Practice Questions
with Confirmed Answers | 100% Accurate |
Graded A+
• L7: What are the three phases in the history of SDN? -✓✓1. Active
networks
2. Control and data plane separation
3. OpenFlow API and network operating systems
• L7: Summarize each phase in the history of SDN. -✓✓1. Active
networks
2. Control and data plane separation
3. OpenFlow API and network operating systems
Active networks
> Researchers wanted to test new ideas to improve network services.
This required standardization of new protocols by the IETF which was a
slow/frustrating process.
> More active networks which wanted to open up network control.
> Community belief: simplicity of the network core was vital to internet
success.
The pushes that encouraged active networking:
,> Reduction in computation cost
> PL Advancement (like java)
> Advances in rapid code compilation and formal methods.
Active networking envisioned unified control that could replace
individually managing these boxes.
Active networks made three major contributions related to SDN:
> Programmable functions in the network to lower the barrier of
innovation
> Introduced the idea of using programmable networks to overcome the
slow speed of innovation in networking.
Active networking produced a framework that described a platform that
would support experimentation with different programming models.
This led to network visualization.
Active networking was more involved in redesigning the architecture of
networks, so not as much emphasis was given to performance and
security. Since there were no specific short-term problems that active
networks solved, it was harder to see widespread deployment.
The next efforts had a more focused scope and distinguished between
control and data planes. This difference made it easier to focus on
innovation in a specific plane and inflict widespread change.
,Control and data plane separation
> Network operators were looking for better network-management
functions such as control over paths to deliver traffic.
> Identified that the challenge in network management depended on the
way existing routers and switches tightly int
• Expanded History -✓✓Active networks
Intro
Slow and frustrating process to standardize protocols fostered the push
for active networks trying to open up network control
Active networks with their network API went against the concept of
keeping the core simple
2 types of programming models in active networking:
Capsule model - carried in-band in data packets
Programmable router/switch model - established by out-of-band
mechanisms
Technology push - The pushes that encouraged active networking were:
Reduction in computation cost (more processing into the network).
Advancement in programming languages. (Java: platform portability,
code execution safety, and VM (virtual machine) technology to protect
the active node in case of misbehaving programs).
Advances in rapid code compilation and formal methods.
Funding from agencies such as DARPA (U.S. Defense Advanced
Research Projects Agency) for a collection promoted interoperability
among projects. There were no short-term use cases.
Use pull - The use pulls for active networking were:
, Network service provider frustration concerning the long timeline to
develop and deploy new network services.
Third party interests to add value by implementing control at a more
individualistic nature. This meant dynamically meeting the needs of
specific applications or network conditions.
Researchers' interest in having a network that would support large-scale
experimentation.
Unified control over middleboxes. Active networking envisioned unified
control that could replace individually managing these boxes.
Active networks contributions related to SDN:
Programmable functions in the network to lower the barrier to
innovation.
While many early visions for SDN concentrated on increasing
programmability of the control-plane, active networks focused on the
programmability of the data-plane.
The concept of isolating expe
• L7: What is the function of the control and data planes? -✓✓Control
plane - controls forwarding behavior of routers, such as routing
protocols and network middlebox configurations.
Data plane - performs actual forwarding as dictated by the control plane.
IP forwarding and layer 2 switching are functions of the data plane.
• L7: Why separate the control from the data plane? -✓✓The reasons we
separate the two are:
