1. OpenFlow/SDN tutorial OFC/NFOEC March, 2012
Srini Seetharaman
Deutsche Telekom
Silicon Valley Innovation Center 1

2. Goals of this Tutorial By the end, everyone should know:
why do we need OpenFlow/SDN?
what is it?
how it works?
where it is going?
how will it benefit carriers?
What: protocol, 2 2

3. Why OpenFlow? 3

4. Specialized Packet Forwarding Hardware
The Ossified Network
Routing, management, mobility management, access control, VPNs, …
Feature
Feature
Million of lines of source code
6000+ RFCs
Barrier to entry
Operating
System
Specialized Packet Forwarding Hardware
Billions of gates
Bloated
Power Hungry
Many complex functions baked into the infrastructure
OSPF, BGP, multicast, differentiated services, Traffic Engineering, NAT, firewalls, MPLS, redundant layers, …
An industry with a “mainframe-mentality”, reluctant to change 4 4

5. none have all the desired attributes!
Open Systems
Performance Fidelity
Scale
Real User Traffic?
Complexity
Open
Simulation
medium no
yes
Emulation
low
Software Switches
poor
NetFPGA
high
Network Processors
Vendor Switches
gap in the tool space
none have all the desired attributes! 5

6. Current Internet Closed to Innovations in the Infrastructure Closed
App
Operating
System
App
Specialized Packet Forwarding Hardware
Operating
System
App
Specialized Packet Forwarding Hardware
Operating
System
The next 3 slides are a set of animation to show how we enable innovation:
- Infrastructure is closed to innovation and only driven by vendors. Consumers have little say
- Business model makes it hard for new features to be added
App
Specialized Packet Forwarding Hardware
Operating
System
Specialized Packet Forwarding Hardware
App
Operating
System
Specialized Packet Forwarding Hardware 6

7. “Software Defined Networking” approach to open it
Network Operating System
App
Operating
System
App
Specialized Packet Forwarding Hardware
Operating
System
App
Specialized Packet Forwarding Hardware
Operating
System
How do we redefine the architecture to open up networking infrastructure and the industry!
By bring to the networking industry what we did to the computing world
App
Specialized Packet Forwarding Hardware
Operating
System
Specialized Packet Forwarding Hardware
App
Operating
System
Specialized Packet Forwarding Hardware

8. The “Software-defined Network”
2. At least one good operating system
Extensible, possibly open-source
3. Well-defined open API
App
App
App
Network Operating System
1. Open interface to hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Switches, routers and other middleboxes are dumbed down
The key is to have a standardized control interface that speaks directly to hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware

9. How does OpenFlow work? 9

10. Ethernet Switch 10

11. Control Path (Software) Control Path
Data Path (Hardware) 11

12. OpenFlow Controller Control Path OpenFlow Data Path (Hardware)
OpenFlow Protocol (SSL/TCP)
Control Path
OpenFlow
Data Path (Hardware) 12

13. OpenFlow Client Controller PC OpenFlow Example Software Layer MAC src
Flow Table
MAC
src
dst IP
Src
Dst
TCP
sport
dport
Action
Hardware
Layer *
port 1
port 1
port 2
port 3
port 4 13

14. OpenFlow usage
Controller PC
Alice’s Rule
Alice’s code
OpenFlow Switch
Decision?
OpenFlow
Protocol
OpenFlow Switch
How the actual protocol works
OpenFlow Switch
OpenFlow offloads control intelligence to a remote software 14 14

15. OpenFlow Basics Flow Table Entries
Rule
Action
Stats
Packet + byte counters
Forward packet to zero or more ports
Encapsulate and forward to controller
Send to normal processing pipeline
Modify Fields
Any extensions you add!
Now I’ll describe the API that tries to meet these goals.
Switch
Port
VLAN ID
VLAN
pcp
MAC
src
MAC
dst
Eth
type IP
Src IP
Dst IP
ToS IP
Prot L4
sport L4
dport
+ mask what fields to match 15 15

16. Examples Switching Flow Switching Firewall Switch Port MAC src dst Eth
type
VLAN ID IP
Src
Dst
Prot
TCP
sport
dport
Action * *
00:1f:.. * * * * * * *
port6
Flow Switching
Switch
Port
MAC
src
dst
Eth
type
VLAN ID IP
Src
Dst
Prot
TCP
sport
dport
Action
port3
00:20..
00:1f..
0800
vlan1 4
17264 80
port6
Firewall
Switch
Port
MAC
src
dst
Eth
type
VLAN ID IP
Src
Dst
Prot
TCP
sport
dport
Action * * * * * * * * * 22
drop 16

17. Examples Routing VLAN Switching Switch Port MAC src dst Eth type VLANID IP
Src
Dst
Prot
TCP
sport
dport
Action * * * * * * * * *
port6
VLAN Switching
Switch
Port
MAC
src
dst
Eth
type
VLAN ID IP
Src
Dst
Prot
TCP
sport
dport
Action
port6,
port7,
port9 * *
00:1f.. *
vlan1 * * * * * 17

18. OpenFlow: a pragmatic compromise
+ Speed, scale, fidelity of vendor hardware
+ Flexibility and control of software and simulation
Vendors don’t need to expose implementation
Leverages hardware inside most switches today (ACL tables) 18

19. Centralized vs Distributed Control Both models are possible with OpenFlow
Centralized Control
Distributed Control
Controller
Controller
OpenFlow
Switch
OpenFlow
Switch
Controller
OpenFlow
Switch
OpenFlow
Switch
Controller
OpenFlow
Switch
OpenFlow
Switch 19

20. Flow Routing vs. Aggregation Both models are possible with OpenFlow
Flow-Based
Every flow is individually set up by controller
Exact-match flow entries
Flow table contains one entry per flow
Good for fine grain control, e.g. campus networks
Aggregated
One flow entry covers large groups of flows
Wildcard flow entries
Flow table contains one entry per category of flows
Good for large number of flows, e.g. backbone 20

21. Reactive vs. Proactive (pre-populated) Both models are possible with OpenFlow
First packet of flow triggers controller to insert flow entries
Efficient use of flow table
Every flow incurs small additional flow setup time
If control connection lost, switch has limited utility
Proactive
Controller pre-populates flow table in switch
Zero additional flow setup time
Loss of control connection does not disrupt traffic
Essentially requires aggregated (wildcard) rules 21

22. Usage examples openflow.org/videos Alice’s code:
Simple learning switch
Per Flow switching
Network access control/firewall
Static “VLANs”
Her own new routing protocol: unicast, multicast, multipath
Home network manager
Packet processor (in controller)
IPvAlice
openflow.org/videos
VM migration
Server Load balancing
Mobility manager
Power management
Network monitoring and visualization
Network debugging
Network slicing
What is possible in the controller? Anything that needs intelligent routing of a flow
At Stanford, we have even shown how OpenFlow may be used for:
VM migration
Power managem ent
Load balancing
Network monitorin g and debugging
Easier network visualizati on
… and much more you can create! 22 22

23. Topology discovery
OpenFlow controller view is not always complete. For instance, what does the controller see here?
OF switch
OF switch
Non-OF switch X Y
Host B
Host A
Non-OF switch
Internet
Host C

24. Quiz Time
How do I provide control connectivity? Is it really clean slate?
Why aren’t users complaining about time to setup flows over OpenFlow? (Hint: What is the predominant traffic today?)
Considering switch CPU is the major limit, how can one take down an OpenFlow network?
How to perform topology discovery over OpenFlow-enabled switches?
What happens when you have a non-OpenFlow switch inbetween?
What if there are two islands connected to same controller?
How scalable is OpenFlow? How does one scale deployments? 24

25. What can you not do with OpenFlow ver1.1
Non-flow-based (per-packet) networking
e.g., Handling pkt 1 differently from pkt 2 of same flow
yes, this is a fundamental limitation
BUT OpenFlow provides the plumbing to connect devices
New forwarding primitives
BUT provides a nice way to integrate them through extensions
New packet formats/field definitions
BUT a generalized OpenFlow (2.0) is on the horizon
Optical Circuits
BUT efforts underway to apply OpenFlow model to circuits
Low-setup-time individual flows
BUT can push down flows proactively to avoid delays 25

26. Where is it going? The Open Networking Foundation:
Textbox Headline
The founding Consortium
Adopter Members (as of Feb 2012)
List of Members:
Big Switch Networks
Broadcom
Brocade
Ciena
Cisco
Citrix
Comcast
CompTIA
Cyan
Dell
Elbrys
Ericsson
ETRI
Extreme Networks
EZchip
Force10Network s
Fujitsu
Netronom e
Nicira Networks
Nokia Siemens Networks
Plexxi Inc.
Pronto Systems
Radware
Riverbed Technolog y
Samsung
Spirent
Tencent
Texas Instrument s
Vello Systems
VMware
ZTE Corporatio n
Hitachi HP
Huawei
IBM
Infoblox
Intel
IP Infusion
Ixia
Juniper Networks
Korea Telecom
LineRate Systems
LSI
Marvell
Mellanox
Metaswitch Networks
Midokura
NEC
Netgear
Promoter Members:
Operators and service providers
Make up the board of directors
Have voting rights
Representative of DTAG is Bruno Orth (GTN S&A)

27. Where it’s going OF v1.1: Extensions for WAN
multiple tables: leverage additional tables
tags and tunnels
multipath forwarding
OF v1.2: Extensible Match structure
Required fields includes IPv6 27

28. Where it’s going
OF v2+
generalized matching and actions: an “instruction set” for networking
Several other working groups have been created:
Hybrid group: Specifies how OpenFlow can be included into legacy switches without assuming clean-slate
Config group: Will specify an independent protocol that will help configure OpenFlow parameters out-of-band
.... And more 28

29. OpenFlow Implementations (Switch and Controller)29

30. OpenFlow building blocks
Monitoring/ debugging tools
oftrace
oflops
openseer
Stanford Provided
Controller Applications
ENVI (GUI)
LAVI
n-Casting
Aggregation
NOX
Beacon
Helios
Maestro
SNAC
Controller
Slicing
Software
Expedient
FlowVisor
There are components at different levels that work together in making it work
The commercial switch details will follow in next slide
There are a plethora of applications possible. I only list those available at Stanford
Commercial Switches
Stanford Provided
Software
Ref. Switch
NetFPGA
Broadcom
Ref. Switch
HP, NEC, Pronto, Juniper.. and many more
OpenFlow
Switches
OpenWRT
PCEngine WiFi AP
OpenVSwitch 30

31. Current SDN hardware More coming soon... Juniper MX-series NEC IP8800
WiMax (NEC)
HP Procurve 5400
Netgear 7324
PC Engines
Pronto 3240/3290
Ciena Coredirector
More coming soon... 31

32. Commercial Switch Vendors
Model
Virtualize
Notes
HP Procurve 5400zl or 6600
1 OF instance per VLAN
LACP, VLAN and STP processing before OpenFlow
Wildcard rules or non-IP pkts processed in s/w
Header rewriting in s/w
CPU protects mgmt during loop
NEC IP8800
OpenFlow takes precedence
Most actions processed in hardware
MAC header rewriting in h/w
Pronto 3290 or with Pica8 or Indigo firmware
1 OF instance per switch
No legacy protocols (like VLAN and STP)
All support ver 1.0
All have approx 1500 flow table entry limit 32

33. Open-source controllers
Vendor
Notes
Nicira’s NOX
GPL
C++ and Python
SNAC
Code based on NOX0.4
Enterprise network
C++, Python and Javascript
Currently used by campuses
Vendor
Notes
Stanford’s Beacon
BSD-like license
Java-based
Maestro (from Rice Univ)
GPL
Based on Java
NEC’s Trema
Open-source
Written in C and Ruby
Included test harness 33

34. Virtualizing OpenFlow34

35. Virtualization or “Slicing”
Trend
Controller 1
App
Controller 2
Virtualization or “Slicing”
OpenFlow
NOX
(Network OS)
Network OS
App
App
App
Windows
(OS)
Linux
Mac OS
Windows
(OS)
Linux
Mac OS
Windows
(OS)
Linux
Mac OS
Virtualization layer
x86
(Computer)
Hidden slide (just for backup reasons)
Shows how far along we can go in opening up the network
Computer Industry
Network Industry 35

36. Virtualization or “Slicing” Layer
Isolated “slices”
Many operating systems, or
Many versions
App
Network Operating System 1
Network Operating System 2
Network Operating System 3
Network Operating System 4
Open interface to hardware
Virtualization or “Slicing” Layer
Open interface to hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware 36

37. Switch Based Virtualization Exists for NEC, HP switches but not flexible enough
Controller
Research VLAN 2
Flow Table
Controller
Research VLAN 1
Flow Table
Production VLANs
Normal L2/L3 Processing
Experiments running on PRODUCTION infrastructure
Key to get scale, key to get traffic on the network
(e.g. can’t just do a reset...) 37

38. FlowVisor-based Virtualization
Heidi’s
Controller
Craig’s
Controller
Aaron’s
Controller
Topology discovery is per slice
OpenFlow
Protocol
OpenFlow FlowVisor & Policy Control
OpenFlow
Switch
OpenFlow
Protocol
OpenFlow
Switch
OpenFlow
Switch 38

39. FlowVisor-based Virtualization
http
Load-balancer
Multicast
Broadcast
Separation not only
by VLANs, but any
L1-L4 pattern
OpenFlow
Protocol
dl_dst=FFFFFFFFFFFF
tp_src=80, or tp_dst=80
OpenFlow
FlowVisor & Policy Control
OpenFlow
Switch
OpenFlow
Protocol
OpenFlow
Switch
OpenFlow
Switch 39

40. FlowSpace: Maps Packets to Slices

41. FlowVisor Message Handling
OpenFlow
Firmware
Data Path
Alice
Controller
Bob
Cathy
FlowVisor
Rule
Policy Check:
Is this rule allowed?
Policy Check:
Who controls this packet?
Full Line Rate
Forwarding
Exception
Packet
Packet

42. Use Case: New CDN - Turbo Coral ++
Basic Idea: Build a CDN where you control the entire network
All traffic to or from Coral IP space controlled by Experimenter
All other traffic controlled by default routing
Topology is entire network
End hosts are automatically added (no opt-in)
Switch
Port
MAC
src
MAC
dst
Eth
type
VLAN ID IP
Src IP
Dst IP
Prot
TCP
sport
TCP
dport *
84.65.*
Researcher *
Admin 42

43. OpenFlow/SDN for carriers43

44. SDN is a hammer for what nail?

45. 1. Packet and Circuit convergence
Most service providers own and operate 2 independent networks : IP and Transport
managed and operated independently
minimal cross-layer awareness
resulting in duplication of functions and resources in multiple layers
and significant capex and opex burdens
Convergence to reduce costs and provide value-added services.
The Flow Abstraction presents a unifying abstraction

46. OpenFlow-based unified control plane
Packet flows
Circuit flows
using the cross-connect table in circuit switches
Switch
Port
MAC
src
dst
Eth
type
VLAN ID IP
Src
Dst
Prot
TCP
sport
dport
Action
VCG
Signal
Type
VCG
Signal
Type

47. pac.c Controller Converged Network Interface: OpenFlow Protocol
Unified
Control
Plane
Interface: OpenFlow Protocol
Packet &
Circuit Switches
Converged Network

48. Demonstration of pac.c NOX OpenFlow Protocol GE links
NEW YORK
SAN
FRANCISCO
GE links
OC-48 links (2.5 Gbps)
HOUSTON 48

49. 2. Improving IP/MPLS control
Basic Idea
Retain MPLS data-plane operations
Replace IP/MPLS control plane
Demonstrate TE & its features
All made simpler – some greatly (eg. AutoRoute)
Some made possible only with SDN (eg. global-optimization)
TE 2.0
VPNs 2.0
Optimized FRR/ AutoBw
MPLS-TP Control
Multi-layer Control
Routing
Discovery
Label Distribution
Recovery
NETWORK OPERATING SYSTEM

50. Summary
OpenFlow/SDN is evolving to facilitate an ecosystem for innovation
OpenFlow is being deployed in over 100 organizations world-wide
GEC9 in Nov, 2010 showcased nation-wide OF
Internet 2 and NLR starting to serve as the GENI Backbone
OpenFlow is essential for Service Providers
Custom control for Traffic Engineering
Combined Packet/Circuit switched networks

51. Are you innovating in your network?51