What  OpenFlow  Is  

Mar2n  Casado  

Acknowledgements  Ben   Pfaff,   JusAn   PeBt,   Nick   McKeown,   ScoG   Shenker,   Jianying   Luo,   Natasha  

Gude,   Teemu  Koponen,  DK  Moon,   Ben   Pfaff,   Peter   Balland,   Keith  Amidon,  Dan  

Boneh,  Tal  Garfinkel,  Michael  Freedman,  Aditya  Akella,  Daniel  Wendlant,  Gregory  

Watson,   John   Lockwood,   Mendel   Rosenblum,   Reid   Price,   David   Erickson,   Tim  

Hinrichs,   John  Mitchell,   Henrik   Amren,   Junda   Liu,   Rob   Sherwood,   Jesse  Grosse,  

Ethan   Jackson,   Jeremy   Stribling,   Alex   Yip,   KK   Yap,   Murphy  McCauley,   Brandon  

Heller,  Rajiv  Ramanathan,  Jean  Tourhilles,  Edward  Crabbe,  ScoG  Whyte,  Min  Zuo,  

Leon  PouAeksi,  Jim  Wanderer,  Igor  Ganichev,  Teemu  Koponen,  Andrew  Lambeth,  

Pankaj   Thakker,   Ronghua   Zhang,   Guru   Parulkar,   Dan   PiG,   Curt   Beckman,   Ali  

Yahya,   Kay   Ousterhaut,   David   Ward,   Jan   Medved,   Joe   Tardo,   Puneet   Agarwal,  

Dave  McDyson,  Romain  Lenglet,  Simon  Horman  …  and  many,  many  others  

Prehistory  (2002-­‐2003)  

Paradise  Lost?  

•  Limited  redundancy  •  Constrained  topology  •  Poor  response  to  dynamic  events  •  Scaling  limited  by  operaAonal  complexity    

Policy  

Port  security  

policy  rouAng  

ACLs  

VLANS  

Networking  in  PracAce  

L3 table

Switch/Router

 A  

 B  

 C  

Packet In

Packet Out

L2 table + VLAN

ACL+ QoS VRF Context

Port groups

Distributed Forwarding State

Manual configuration State

The  Problems  …  

•  Humans  suck  at  state  management    

•  No  well  defined  APIs  for  datapath  state  

•  No  general  distributed  algorithms  for  all  datapath  state  

 

Developing  OpenFlow  (2004-­‐Now)  

"How  to  program  a  network”  

"How  to  programmaAcally  manage  all  of  the  datapath  state  in  the  network"  

Problem:  Poor  Forwarding  AbstracAons  

L3 table

Switch/Router

 A  

 B  

 C  

Packet In

Packet Out

L2 table + VLAN

ACL+ QoS VRF Context

Port groups

•  Fixed  funcAon  •  Oden  expose  implementaAon  details  •  Non-­‐standard/non-­‐existent  state  management  APIs    

SoluAon:  Generalize  Dataplane  

Flow table

Switch/Router

 A  

 B  

 C  

Packet In

Packet Out

Flow table Flow table

OpenFlow  

Problem:    Distributed  CompuAng  is  Hard  

Forwarding  Hardware  

Forwarding  Hardware  

Forwarding  Hardware  

Forwarding  Hardware  

Forwarding  Hardware  

Software control

Software control Software

control

Software control

Software control

SoluAon:  Decouple  DistribuAon  Model  from  Topology  

Forwarding  Hardware  

Forwarding  Hardware  

Forwarding  Hardware  

Forwarding  Hardware  

Forwarding  Hardware  

OpenFlow OpenFlow

OpenFlow

OpenFlow

OpenFlow

Software control

A  Sensible  (Humdrum)  System  Stack  

Decouple  Control  Logic  

Hardware  

Hardware  AbstracAon  Layer  

Control  ApplicaAon  

A  Sensible  (Humdrum)  System  Stack  

Decouple  Control  Logic  

Hardware  

Hardware  AbstracAon  Layer  

Ethane  Distributed  Compiler  

Hardware  

Policy  

The  Network  OperaAng  System  

Decouple  Control  Logic  

Hardware  

Hardware  AbstracAon  Layer  

Control  ApplicaAon  

The  Network  OperaAng  System  

Decouple  Control  Logic  

Hardware  

Hardware  AbstracAon  Layer  

Network  OS  

ApplicaAon  

OpenFlow  

Hardware  

SDN  

OpenFlow/SDN  FAQ  

What  is  the  Primary  Value  ProposiAon?  

•  Ability  to  innovate  within  the  network  

•  Horizontal  integraAon  – Market  efficiency  – Rapid  innovaAon  at  each  layer  

Does  OpenFlow  Offer  New  FuncAonality?  

•  Not  really  …  

Does  SDN  Scale?  

•  Yes  

A  RestrospecAve  on  the  Future  of  OpenFlow  (Now-­‐??)  

Is  OpenFlow  …  

•  …  a  new  idea?    

•  …  well  designed?    

•  …  a  path  to  new  funcAonality?    

So  What  is  the  Cause  of  its  Success?  

You