1. An Introduction to Software Defined Networking and OpenFlow
Vic Thomas

2. Reserve Resources (Step 1 of Instructions)
Slice 1: Controller
Portal RSpec: XEN OpenFlow Controllers
Slice 2: Network
Portal RSpec: OpenFlow OVS all XEN
Create both slices on the same InstaGENI rack
Instructions at:

3. Software Defined Networking Basics
OpenFlow

4. Software Defined Networking Basics

5. “The current Internet is at an impasse because new architecture cannot be deployed or even adequately evaluated” [PST04]
[PST04]: Overcoming the Internet Impasse through Virtualization, Larry Peterson, Scott Shenker, Jonothan Turner. Hotnets 2004

6. Software Defined Networking…
Enables innovation in networking
Changes practice of networking
A Purpose-Built Global Network:
Google's Move to SDN
CACM March 2016, pp 46–54

7. Smarts baked into switch
SDN Basics
Smarts baked into switch
Network Switch

8. Smarts moved out of switch
SDN Basics
Open API
Controller
Smarts moved out of switch
Network Switch

9. SDN Basics
From:
Forwarding table entries added by vendor provided logic internal to switch
MATCH
ACTION
dst subnet X
output port 48
dst subnet Y
output port 47
dst MAC: 00:00:00:00:00:01
output port 2
output port 5
SDN
To:
Table entries added by external controller written by anyone
src subnet Z
drop
TCP port 80
output port 10
Switch Forwarding Table

10. SDN Basics
Controller
One controller can manage many switches

11. SDN Enables Network Function Virtualization
Controller
NAT
firewall
DHCP
DNS
switch
VPN
router
gateway
proxy
access point
Network Device
Many network functions can be implemented
using a generic network device

12. NFV: Network Function Virtualization
Slide from:

13. Software Defined Infrastructures
Physical infrastructure
User defined virtual networks with compute, storage, networking
Everything is virtualized Highly optimized networks Dynamic reconfigurations Network snapshotting Network engineering ~ ~ Software engineering
Orchestration Layer (e.g. ONOS)
Figure adapted from

14. SDN Benefits* External control Centralized control
Enables network Apps
Fosters innovation: Not limited to vendor provided switch logic
Leverages general-purpose computers (Moore’s Law)
Drives down costs: Network hardware becomes a commodity
Centralized control
Enterprise-wide optimization and planning
Dynamic network reconfiguration
One place for apps to interact (auth & auth, etc)
* OpenFlow: A radical New idea in Networking, Thomas A. Limoncelli CACM 08/12 (Vol 55 No. 8)

15. There an now many more ways of
SDN Drawbacks
Unexpected interactions between features
Controller reliability and stability
Controller security (runs on a general purpose computer and OS)
There an now many more ways of
messing up a nework

16. OpenFlow

17. OpenFlow is an SDN API OpenFlow is the most widely implemented
controller-switch API

18. OpenFlow Versions (‘12/’13) OpenFlow 1.3.x
(‘11) Open Networking Foundation (ONF) formed to shepherd standards
(‘12/’13) OpenFlow 1.3.x
Complex &
support in progress
(Dec ’09) OpenFlow 1.0.0
Simple & widely supported
(Dec’ 14) OpenFlow 1.5
(Oct ‘13) OpenFlow 1.4
(Feb ‘11) OpenFlow 1.1.0
Not implemented by HW vendors
(Nov‘13) OpenFlow 1.0.2
(Dec ‘11) OpenFlow 1.2
First ONF standard

19. OpenFlow Protocol (SSL/TCP)
The controller is responsible for populating forwarding table of the switch
In a table miss the switch asks the controller
Switch
Data Path (Hardware)
Control Path
OpenFlow
Any Host
OpenFlow Controller
OpenFlow Protocol (SSL/TCP)
Modified slide from :

20. OpenFlow Protocol (SSL/TCP)
OpenFlow in Action
Host1 sends a packet
If there are no rules for handling this packet
Forward packet to the controller
installs a rule on the forwarding table (flow table)
Subsequent packets do not go through the controller
Switch
Data Path (Hardware)
Control Path
OpenFlow
Any Host
OpenFlow Controller
OpenFlow Protocol (SSL/TCP)
host2
host1
Modified slide from :

21. OpenFlow 1.0 Basics Rule Action Stats Packet + byte counters
Forward packet to port(s)
Encapsulate and forward to controller
Drop packet
Send to normal processing pipeline
Modify Fields
Switch
Port
VLAN ID
VLAN
PCP
MAC
src
MAC
dst
Eth
type IP
Src IP
Dst IP
Prot IP
ToS
TCP
sport
TCP
dport
Now I’ll describe the API that tries to meet these goals.
+ mask what fields to match
slide from : 21

22. OpenFlow controllers Open source controller frameworks
NoX – C++
PoX - Python
OpenDaylight - Java
FloodLight - Java
Trema – C / Ruby
Maestro - Java
Ryu - Python
Proprietary controllers
Mostly customized solutions based on Open Source frameworks
ProgrammableFlow - NEC

23. Running OpenFlow Experiments
Debugging OpenFlow experiments is hard:
Network configuration debugging requires coordination
Many networking elements in play
No console access to the switch
Before deploying your OpenFlow experiment test your controller.

24. Exercise: Use the Ryu controller to set up simple flows

25. OpenFlow 1.0 Intro Exercise
Write simple controllers to control the traffic between the three hosts.

26. Major Steps Step 2 of instructions
2. Configure your switch
2a. Connect switch ports to Ethernet interfaces of VM running switch
2b. Point switch to controller
Controller can by anywhere on the Internet. Yours runs on a GENI VM in a different slice.
host2
host1
OVS
switch name: br0
controller
host3

27. Run Experiments Simple learning switch Port forwarding Server proxy
OVS switch acts as a regular switch: Learns which MAC addresses are connected to which ports and forwards traffic accordingly
Port forwarding
Traffic from Host 1 to Host 2 on Port 5000 gets forwarded to Port 6000 on Host 2
Server proxy
Traffic from Host 1 to Host 2 gets forwarded to Host 3

28. Tips Cut and paste the curl commands
Keep online version of instructions open
You will have multiple terminals open to each of Hosts 1, 2, 3, controller and switch. Make sure your are typing your commands in the right window.

29. Instructions: