CS6250 Exam 2
Study online at https://quizlet.com/_a16fab
1. L7: What spurred > SDN arose to make CN more programmable
the development > Networks are complex/difficult to manage due to the diversity of equipment on
of Software De- the network and proprietary technologies for the equipment
fined Networking > These made them highly complex, slow to innovate, and drove up the costs of
(SDN)? running a network.
SDN divides the network into two planes (separation of tasks):
1. control plane
2. data plane.
2. L7: What are the 1. Active networks
three phases in 2. Control and data plane separation
the history of 3. OpenFlow API and network operating systems
SDN?
3. L7: Summarize 1. Active networks
each phase in the 2. Control and data plane separation
history of SDN. 3. OpenFlow API and network operating systems
Active networks
> Researchers wanted to test new ideas to improve network services. This re-
quired 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 man-
aging these boxes.
,CS6250 Exam 2
Study online at https://quizlet.com/_a16fab
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 integrated the control and data planes.
> Efforts the separate the two began:
>> Higher link speeds in backbone networks led vendors to implement packet
forwarding directly in the hardware
>> ISPs found it hard to meet the increasing demands for greater reliability and
new services.
Two main innovations: Open interface between control and data planes AND
logically centralized control of the network
Differed from active networking, it:
> Focused on spurring innovation by/for network administrators rather than end
,CS6250 Exam 2
Study online at https://quizlet.com/_a16fab
users/researchers.
> Emphasized programmability in the control domain rather than the data do-
main.
> Worked to network-wide visibility rather than device
Attempts to separate control and data planes resulted in two concepts used in
further SDN design:
> Logically centralized control using an open interface to the data plane.
> Distributed state management - There was skepticism to moving away from a
simple network where all have a common view of the network state to one where
the router only had a local view of the outcome of route-selection. This concept
of separation of planes helped researchers think clearly about distributed state
management.
OpenFlow API and network operating systems
> OpenFlow was born out of interest in the idea of network experimentation at
scale, by researchers and funding agencies.
> OpenFlow built on the existing hardware and enabled more functions than
earlier route controllers. Enabled immediate deployment.
The basic working of an OpenFlow switch: Each switch contains a table of pack-
et-handling rules. Each rule has a pattern, list of actions, set of counters and a
priority. When an OpenFlow switch receives a packet, it determines the high-
est priority matching rule, performs the associated action and increments the
counter.
OpenFlow was adopted in the industry, unlike its predecessors.
Companies started investing more in programmers to write control programs,
and less in proprietary switches that could not support new features easily. This
allowed many smaller players to become competitive in the market by supporting
capabilities like OpenFlow.
Key effects that OpenFlow had were:
, CS6250 Exam 2
Study online at https://quizlet.com/_a16fab
Generalizing network devices and functions
Vision of a network operating systems
Distributed state management techniquesr
4. Expanded Histo- Active networks
ry 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 execu-
tion 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 experi-
mentation.
Unified control over middleboxes. Active networking envisioned unified control
that could replace individually managing these boxes.
Study online at https://quizlet.com/_a16fab
1. L7: What spurred > SDN arose to make CN more programmable
the development > Networks are complex/difficult to manage due to the diversity of equipment on
of Software De- the network and proprietary technologies for the equipment
fined Networking > These made them highly complex, slow to innovate, and drove up the costs of
(SDN)? running a network.
SDN divides the network into two planes (separation of tasks):
1. control plane
2. data plane.
2. L7: What are the 1. Active networks
three phases in 2. Control and data plane separation
the history of 3. OpenFlow API and network operating systems
SDN?
3. L7: Summarize 1. Active networks
each phase in the 2. Control and data plane separation
history of SDN. 3. OpenFlow API and network operating systems
Active networks
> Researchers wanted to test new ideas to improve network services. This re-
quired 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 man-
aging these boxes.
,CS6250 Exam 2
Study online at https://quizlet.com/_a16fab
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 integrated the control and data planes.
> Efforts the separate the two began:
>> Higher link speeds in backbone networks led vendors to implement packet
forwarding directly in the hardware
>> ISPs found it hard to meet the increasing demands for greater reliability and
new services.
Two main innovations: Open interface between control and data planes AND
logically centralized control of the network
Differed from active networking, it:
> Focused on spurring innovation by/for network administrators rather than end
,CS6250 Exam 2
Study online at https://quizlet.com/_a16fab
users/researchers.
> Emphasized programmability in the control domain rather than the data do-
main.
> Worked to network-wide visibility rather than device
Attempts to separate control and data planes resulted in two concepts used in
further SDN design:
> Logically centralized control using an open interface to the data plane.
> Distributed state management - There was skepticism to moving away from a
simple network where all have a common view of the network state to one where
the router only had a local view of the outcome of route-selection. This concept
of separation of planes helped researchers think clearly about distributed state
management.
OpenFlow API and network operating systems
> OpenFlow was born out of interest in the idea of network experimentation at
scale, by researchers and funding agencies.
> OpenFlow built on the existing hardware and enabled more functions than
earlier route controllers. Enabled immediate deployment.
The basic working of an OpenFlow switch: Each switch contains a table of pack-
et-handling rules. Each rule has a pattern, list of actions, set of counters and a
priority. When an OpenFlow switch receives a packet, it determines the high-
est priority matching rule, performs the associated action and increments the
counter.
OpenFlow was adopted in the industry, unlike its predecessors.
Companies started investing more in programmers to write control programs,
and less in proprietary switches that could not support new features easily. This
allowed many smaller players to become competitive in the market by supporting
capabilities like OpenFlow.
Key effects that OpenFlow had were:
, CS6250 Exam 2
Study online at https://quizlet.com/_a16fab
Generalizing network devices and functions
Vision of a network operating systems
Distributed state management techniquesr
4. Expanded Histo- Active networks
ry 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 execu-
tion 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 experi-
mentation.
Unified control over middleboxes. Active networking envisioned unified control
that could replace individually managing these boxes.
