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Questions?

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Routing Network Traffic

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Introduction

  • What is routing?
  • How do normal routers operate?
  • What is the goal of the SDN model of routing

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What is Routing?

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How do normal routers operate?

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Dynamic routing table:

  • Protocols: IP, BGP, etc.
  • Learns about shortest and fastest path

Static routing table:

  • No changes

These tables live in the distributed routers.

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Openflow Protocol

  • What is openflow?
  • How do we specify rules for open flow
  • Disadvantages? Why do we want better?

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What is Openflow?

  • Protocol with which controller and switch can communicate
  • Can operate over Layer 2 / 3
  • Specify flows that should be added locally to switch routing tables

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Role of SDN in routing

The Decoupling of control and data planes enable the following in routing:

  • Change the routing rules at any time through programming interface
  • Network admin only has to deal with a centralized controller to distribute policies to routers
  • Hardwares are made to be more generic as opposed to the current dedicated hardwares

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Openflow Example

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Topology

Host 1

Host 4

Host 2

Host 3

Switch 1

Switch 2

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POX Controller

  • What is POX?
  • How is this a step up from openflow?

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Topology

Host 1

Host 4

Host 2

Host 3

Switch 1

Switch 2

Switch 3

Switch 4

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POX Example

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Conclusion

  • Software defined network allows for more configurability
  • Do we need a controller?
  • Programmable Switches