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CS 6250 Exam 2|282 Questions with Verified Answers
CS 6250 Exam 2|282 Questions with Verified Answers
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CS 6250 Exam 2|282 Questions withVerified Answers
What are 2 reasons computer networks are complex and difficult to manage
that led to the development of SDN? - -1. Diversity of network equipment
2. Proprietary technology required for equipment
-Why would equipment diversity cause complexity when managing a
network? - -Different software must be used for different protocols (7)
-Why do proprietary technologies cause complexity when managing
networks? - -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? - -Separate tasks into control plane and data plane. (7)
-What are the 3 phases of history of SDN? - -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? - -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? - -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? - -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? - -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? - -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? - -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? - -Data plane (7)
, -What plane do programmable functions in active networks focus on
increasing programmability, and why? - -- Data plane
- isolate experimental traffic from normal traffic (7)
-What were some downfalls of active networking? - -- 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? - -No (7)
-What challenge did control and data plane separation tackle? - -
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? - -1. packet forwarding (data plane) was implemented in
hardware (separate from control plane)
2. ISPs couldn't meet increasing demands for greater reliability and new
services b/c of increasing scope and size
3. servers have much more memory and processing resources - routing
decisions could be done on one server for one ISP network
4. open-source routing lowers barrier to creating prototypes of centralized
routing controllers
(7)
-How did higher link speeds in backbone networks encourage control and
data plane separation? - -packet forwarding implemented in hardware,
separate from control plane (7)
-What 2 innovations led to the control and data plane separation? - -1. open
interface between control and data plane
2. logically centralized control of network(7)
-Was the network centrally controlled logically, physically, or both under
control and data plane separation? - -LOGICALLY centrally controlled(7)
-What are 3 ways control plane and data plane separation differed form
active networks? - -1. Spurred innovation for network ADMINS instead of
users
, 2. emphasized programmability in CONTROL domain instead of data domain
3. worked towards NETWORK-WIDE visibility and control rather than device
level configurations(7)
-Was visibility and control at network level or device level for active
networks? Control/data plane separation? - -Device level
Network level
(7)
-Was programmability in control domain or data domain for active
networks? Control/data plane separation? - -Data domain
control domain
(7)
-Was innovation for network admins or users for active networks?
Control/data plane separation? - -Users
Admins
(7)
-What are 5 use cases for control plane/data plane? - -1. path selection
based on network traffic load
2. minimized disruptions during planned routing changes
3. redirecting or dropping suspected attack traffic
4. allow customer networks more control over network flow
5. offer value added services for virtual private network customers
(7)
-Were control plane and data plane separation efforts focused on managing
routing WITHIN ONE ISP? - -No
some wanted to enable flexible route control across many ASes
(7)
-What 2 concepts resulted from control and data plane separation? - -1.
LOGICALLY centralized control w/ open interface to data plane
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