Lecture 7: 12th November 2019 Flashcards
Software-Defined Networking
What is SDN?
!
Why is there hype around SDN?
!
What does SDN do?
!
Why does making features in networking hardware take so long?
!
Why is the current implementation of the Internet poor?
!
How do commercial interests impede innovation and modification of the Internet?
!
What are the main problems with understanding, managing, and designing networks?
!
What does it mean to say networking is an artifact and not a discipline?
!
What is the control plane of networks?
!
What were the goals of the control planes in early networks?
!
What is the data plane?
!
What is the management plane/
!
How are the data plane and control plane different?
!
How do the timescales of operations by the different network planes compare?
!
What is the difference between routing and forwarding@
!
Which network planes perform routing and forwarding@
!
What are streaming algorithms?
!
What is the function of streaming algorithms in the data plane?
!
What is the main goal of network management? What are its additional goals?
!
What is access control?
!
What is isolation?
!
What is traffic engineering?
!
How did access control work before SDN?
!
How did isolation work before SDN?
!
How did traffic engineering work before SDN?
!
What are the two main methods of traffic engineering (prior to SDN)?
!
What is MPLS?
!
What is OSPF?
!
What is Inter-domain configuration?
!
Why would traditional Inter-domain config not work at scale?
!
What is the current difference between the aims of work on networking now and other disciplines?
!
What is the bus factor?
!
How is the bus factor relevant to the Internet?
!
What are control plane mechanisms?
!
What are the current problems with control plane mechanisms?
!
How has the complexity of networks not caused the Internet to fail?
!
What do you gain from mastering complexity and extracting simplicity? When are they useful?
!
Is networking today concerned with mastering complexity or extracting simplicity? What does this imply?
!
How would we benefit if we were able to transition networking from mastering complexity to extracting simplicity?
!
Do abstractions remove complexity?
no
Do abstractions give modularity?
yes
How did programming go from mastering complexity to extracting simplicity?
!
How can you put networking functionality into abstractions?
!
How can you add abstractions within the data plane?
!
Why is layering important?
!
What is the problem with existing control plane mechanisms?
!
How doy find abstractions for a system?
!
What is the single overall function of the control plane?
!
What are the three main aims of the control plane?
!
How do we currently fulfill the aims of the control plane?
!
What are some concerns with abstractions for the control plane not present for all systems?
!
How can we implement a forwarding abstraction for the control plane?
!
What is OpenFlow?
!
How does OpenFlow work?
!
How can we implement a network state abstraction for the control plane?
!
What is NOS?
!
How does NOS work?
!
What is the impact of NOS and SDN on a network state abstraction for the control plane?
!
How can we abstract the specification of the functionality of the control plane?
!
How could access control be applied to control plane specification mechanisms?
!
What could abstracted specification of the functionality of the control plane lead to?
languages for network spec, acting like a compiler since abstraction means you don’t care about how implemented underneath. Like P4.
What are the subtasks of routing?
!
What are the subtasks of access control?
!
How does network virtualisation apply to abstracted specification of the functionality of the control plane?
!
What is each abstraction within the control plane concerned with?
!
What are the layers that form from the abstractions within the control plane?
!
If abstractions don’t remove complexity why are they still useful?
!
How would network hardware look in an SDN network, with separated data and control plane?
!
How would be the effects of separating which network hardware performed data and control plane functionality?
!
How would of separating which network hardware performed data and control plane make hardware in networking similar to that in computers in general?
!
What is an SDN “killer app”?
!
What are some SDN killer apps?
!
What is the high-level vision for SDNs?
!
What are the components of SDNs?
!
What is a data plane switch?
!
How does a data plane switch work?
!
What is an SDN controller?
!
How does an SDN controller work?
!
What is the southbound API?
!
How does the southbound API work?
!
What is the northbound API?
!
How does the northbound API work?
!
What is a network-control app?
!
How does a network-control app work?
!
What are the components of an SDN controller?
!
What does the interface layer of an SDN controller do>
!
What does the management layer of an SDN controller do?
!
What does the communication layer of an SDN controller do?
!
What is the OpenFlow protocol?
!
What does the OpenFlow protocol do?
!
How do controller-to-switch messages work in OpenFlow?
!
How do switch-to-controller messages work in OpenFlow?
!
What part of SDN is OpenFlow the dominant protocol to implement?
!
How does SDN handle failures in different abstractions/layers?
!
How does SDN handle link state changes?
!
Is SDN too slow?
No. OSPF right now is done every minute and takes multiple minutes to return all the information and make changes.
Which challenges is SDN seeking to address?
!
What is the difference between routing and forwarding? Which SDN planes carry them out?
!
Which hardware implement the data and control planes?
The data plane is the actual switching fabric forwarding.Anything beyond this that needs the processor is the control plane.
What is the problem with MPLS?
Unscalable.
