From the paper's abstract - Software Defined Networking (SDN) is an exciting technology that enables innovation in how we design and manage networks. Although this technology seems to have appeared suddenly, SDN is part of a long history of efforts to make computer networks more programmable. In this paper, we trace the intellectual history of programmable networks, including active networks, early efforts to separate the control and data plane, and more recent work on OpenFlow and network operating systems. We highlight key concepts, as well as the technology pushes and application pulls that spurred each innovation. Along the way, we debunk common myths and misconceptions about the technologies and clarify the relationship between SDN and related technologies such as network virtualization. http://dl.acm.org/citation.cfm?id=2602219

1. The Road to
Software Defined Networking
Nick Feamster, Jennifer Rexford, Ellen Zegura
2013
Papers We Love, Hyderabad - 12 July 2015

2. Agenda
Some Networking Basics
The Paper
Demo

3. Some networking basics

4. and a few definitions
Decides how to forward packets (Routing, Dropping, Firewall Rules)
Does the actual forwarding (or dropping, or filtering) of the data packets
Control Plane
Data Plane

5. The Road to SDN

6. Defining Characteristics
● Separation of the control and the data planes
● Control Plan Consolidation - single CP controls multiple DPs

7. The Roots of SDN
● Ideas in early telephone networks
● Initially used to describe Stanford’s OpenFlow project

8. Timeline
Active Networking Data and Control
Plane Separation
OpenFlow and
Networking
Operating System
1995 2001 2007

9. Active Networking
Vision

10. Active Networking
Models
In-band code Out-of-band code

11. Active Networking
Driving Factors
Technology - Cheaper computing, Virtual machines (sandboxes), WORA, security, a la Java
Users - Faster new service deployment, Finer control to dynamically meet app/network needs, platforms
for scalable research

12. Active Networking
Legacy
Programmable functions in the network
Network virtualization
Unified architecture for "middlebox" orchestration

13. Control & Data Plane Separation
Vision
- Conventional routing protocols were primitive for traffic engineering
- Data and control planes are tightly coupled in conventional routers

14. Control & Data Plane Separation
Driving Factors
Technology - Vendors built packet forwarding logic in data plane hardware
Users - Increased size and complexity of service providers

15. Control & Data Plane Separation
Legacy
- Open interface between control and data planes (ForCES, Netlink)
- Logically centralized control of the network (RCP, SoftRouter)
- Further clean-slate architectures - 4D, Ethane (set the stage for OpenFlow)

16. OpenFlow & the NOS
Vision (and Reality)
- Campus networks @Stanford
- Right balance between full programmability & real world deployment
- Followed by controllers like NOX

17. OpenFlow & the NOS
Driving Factors
Technology - Gradual opening up of switch chipset vendor APIs, Industry demand for more network
device control
Users - People getting together - Equipment vendors, chipset designers, network operators, networking
researchers

18. OpenFlow & the NOS
And after OpenFlow
- Conceptual unification of network devices/functions
- Rise of network operating systems
- Distributed state management techniques (e.g. the Onix controller)

19. Myths about SDN
First packet of every traffic should go to the controller
Controller must be physically centralized (e.g. Google's WAN)
OpenFlow == SDN

20. Network Virtualization
Pre SDN
Packet encapsulation with custom protocols (overlay networks)

21. Network Virtualization
SDN Enables Network Virtualization
Network Virtualization can be used to test and evaluate SDNs

22. Pox SDN Controller Demo

23. References
The paper itself - http://queue.acm.org/detail.cfm?id=2560327
Enabling Innovation in Campus Networks - http://archive.openflow.org/documents/openflow-wp-latest.pdf
POX Controller - http://www.noxrepo.org/pox/about-pox/
OpenFlow - https://www.opennetworking.org/sdn-resources/openflow
Coursera SDN course - https://class.coursera.org/sdn1-001
An attempt to motivate and clarify Software-Defined Networking - https://www.youtube.com/watch?v=WVs7Pc99S7w

24. Image Credits
Switch - By Geek2003 (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Router - https://creativecommons.org/publicdomain/zero/1.0/deed.en
Others are public domain

25. Thank You