Today’s Class
  • Drawbacks of current Networking Paradigms 
   –Motivation for SDN
  • SDN!!!!!
  • OpenFlow: A common SDN API
  • SDN challenges and Use-cases
                             Networking Today: 
      • Distributed, time-consuming and error prone
           –Think BGP, Distance-Vector
                      128.35.6.*/24             128.35.6.*/24     128.35.6.*/24
    128.35.8.*/24     128.35.9.*/24             128.35.9.*/24
            MAC_A            MAC_A                               128.35.9.*/24
            MAC_B            MAC_B                    MAC_E                 MAC_E
            MAC_Y            MAC_Y                    MAC_Z                 MAC_Z
                                                               G          H
                  G          H                                 G          H
                  G          H
                128.35.7.*/24
                               Networking Today: 
      • Distributed, time-consuming and error prone
           –Think BGP, Distance-Vector
                          Distance                   Distance          128.35.6.*/24
    128.35.8.*/24          Vector                     Vector
                                                                     128.35.9.*/24
         Spanning                 Spanning             Spanning                 Spanning 
            Tree                    Tree                  Tree                    Tree
                                                                   G           H
                   G           H                                   G           H
                   G           H
                  128.35.7.*/24
                          Ideally…
    • Managing network in a simple way
    • Directly and explicitly apply policies to network
                  SSpenlitd lo traadffic be otvweere tnh eS 5 reand dlin Sk6!!!
                       accurate network view
                        forwarding state
                                                          G  H
                                            G  H          G  H
                                            G  H
                         Instead …
    • Managing network in a complex way
    • No clear idea of the consequences
                 How can I change distance vector?
                 Is iBGP running in this network?
                 Split load between S5 and S6
                 Should I worry about spanning-tree?
                       Forwarding tables
                       Change weights
                                                         G  H
                                           G  H          G  H
                                           G  H