1. Week 6 Software Defined Networking (SDN): Concepts
Acknowledgement:
Material for several slides is taken from:
The SDN academy, and
Stanford’s “clean slate” program

2. Traditional Network Data plane: forwards packets
Control plane: protocols (spanning tree, OSPF, …)
Distributed protocols (switches are peers)

3. Distributed Network Protocols
Pros:
Resilient to failures
Scalable to large networks
Cons (complexity):
Expensive to manage: protocol experts
Hard to troubleshoot: isolating faults
Hard to evolve: new protocols require standards
Lack of agility is key bottleneck to innovation

4. How to innovate? Experimenter’s dream – vendor’s nightmare
Standard
Network
Processing
User-
defined
Processing
Experimenter writes experimental code on switch/router sw hw
The Stanford Clean Slate Program

5. No obvious way
Commercial vendor won’t open software and hardware development environment
Complexity of support
Market protection and barrier to entry
Hard to build my own
Prototypes are flakey
Software only: Too slow
Hardware/software: Fanout too small (need >100 ports for wiring closet)
The Stanford Clean Slate Program

6. Furthermore, we want… Isolation: Regular production traffic untouched
Virtualized and programmable: Different flows processed in different ways
Equipment we can trust in our wiring closet
Open development environment for all researchers (e.g. Linux, Verilog, etc).
Flexible definitions of a flow
Individual application traffic
Aggregated flows
Alternatives to IP running side-by-side …
The Stanford Clean Slate Program

7. OpenFlow Switching Controller OpenFlow Switch PC Secure sw Channel
OpenFlow Switch specification
OpenFlow Switch PC
OpenFlow
Protocol
SSL
Secure
Channel sw
Flow
Table hw
The Stanford Clean Slate Program

8. SDN: Key Idea
Separate the data and control planes

9. [1] Forwarding abstraction: Flow Table Entry
Rule
Action
Stats
Packet + byte counters
Forward packet to port(s)
Encapsulate and forward to controller
Drop packet
Send to normal processing pipeline
Switch
Port
MAC
src
MAC
dst
Eth
type
VLAN ID IP
Src IP
Dst IP
Prot
TCP
sport
TCP
dport
+ mask
The Stanford Clean Slate Program

10. [2] Distributed State Abstraction: Global network view

11. SDN abstractions
Scott Shenker’s talk at ONS:

12. OpenFlow Usage Models Experiments at the flow level
User-defined routing protocols
Admission control
Network access control
Network management
Energy management
VOIP mobility and handoff …
Experiments at the packet level
Slow: Controller handles packet processing
Fast: Redirect flows through programmable hardware
Modified routers, firewalls, NAT, congestion control…
Alternatives to IP
Experiment-specific controllers
Static or dynamic flow-entries
The Stanford Clean Slate Program

13. Example Experiment at the flow level Mobility
Lots of interesting questions
Management of flows
Control of switches
Access control of users and devices
Tracking user location and motion
The Stanford Clean Slate Program

14. Experiments at the packet level
Controller PC
OpenFlow-enabled
Commercial Switch
Flow
Table
Secure
Channel
Normal
Software
Datapath
Laboratory
The Stanford Clean Slate Program
NetFPGA

15. Benefits of SDN

16. Thinking differently about networking

17. SDN: Platforms (next week)
Hardware (switches):
HP, Juniper, NEC, Cisco, Extreme, Force10
Brocade, Arista, Ericsson, IBM, Intel, Larch, Pica8
Software (controllers):
DC/Cloud: Nicira, Vyatta, Citrix
Enterprise: BigSwitch, Pertino(?)
SP: Cariden, LineRate
Open source: NOX, POX, Floodlight
Research opportunities:
Scalable / distributed / hierarchical controller ?
Programming / policy / debugging ?
Security / agility ?
Application API ? Migration to SDN ?

18. UNSW SDN Infrastructure
Internet
Anchor
Controller
Wireless clients
to SDN testbed
Uniwide WiFi
Campus
Controller
VLAN A (mobile)
UNSW
Wired network
DHCP server will use
EET address block
/27
VLAN B (fixed)
EET
Port 1
SDN testbed
in EET
Port 4
Port 3
Wired clients
to SDN testbed
Port 2
Egress 2: back into campus
network via EET port
Egress 1: via
AARNet wavelength
from UNSW to CSIRO
Internet
Exchange Point

19. AnzSDN: http://www.anzsdn.net/UQ
Traffic generator
Exchange point
UPS
Controller PC
SDN switch 1
SDN switch 2
SDN switch 3
Switched rack PDU
Console tray
Cable mgmt
Macquarie
Uni
UTS
SDN rack
UNSW
CSIRO
Marsfield
Layer-2 inter-connectivity
amongst sites (via AARNet)
Adelaide
Uni
Uni
Wollongong
RMIT
Swinburne
Uni
ANU
SDN rack at each site

20. SDN use-cases (later in course)
Data Center / Cloud services
Inter-DC WAN
Enterprise networks
Service provider WAN
Access/home network (NBN)
Mobile Networks
CDNs