The Raspberry Pi is a low cost computer and you can use it to build your own OpenFlow switch for around $70 ! Learn about what you can and can't do with OpenFlow through experimentation. This share explains how to make the RPi useful since it is not useful as a switch with just 1 Ethernet port, what software to install (Erlang + LINC) and finally how to make your new switch useful since an OpenFlow switch is pretty useless without an OpenFlow controller.

1. Steve Roberts
Turning the Raspberry Pi
into an OpenFlow Switch
+ =

2. Steve Roberts
What is OpenFlow?

OpenFlow is a new concept in data networking

It's a way to implement Software Defined
Networks (SDN)

It's a standard developed by the ONF

Google invented in and they use it

It's likely to be the future of IP networking

3. Steve Roberts
Why is it new?

OpenFlow separates control plane from data
plane

What does that mean?

The decision how packets are routed is handled
separately from actually routing them

The decision how packets are routed can now
be programmed

4. Steve Roberts
So what?

Telecom networks separated control from data
20+ years ago

Separation allowed new services to be created
like: freephone, virtualised switchboards,
mobile phones...

OpenFlow will enable new services to be
created in the data world

It will lower the price point for routing much like
PC architecture did for computing

It will simplify networks

5. Steve Roberts
Why OpenFlow on RPi?

OpenFlow is new, so experimentation is the
best way to learn about it

Raspberry Pi is a cheap computer (~ $40)

Build your own OpenFlow switch or OpenFlow
network so you can learn what OpenFlow can
and can't do.

6. Steve Roberts
The Raspberry Pi

Cheap (~ $40)

Runs Linux

1 Ethernet port

USB ports

7. Steve Roberts
Switches and Routers

Ethernet switches and IP routers have more
than 1 Ethernet port

To be a switch or router you need more than 1
port

RPi only has 1 Ethernet port

Solution: Use USB to add more ports

8. Steve Roberts
Expanded RPi
Rpi $40
USB to Ethernet
adaptors $5
USB to WiFi
adaptors $12
Total cost: $70
Spec:
3x Ethernet
1x WiFi
http://openflow-sdn.blogspot.co.uk/2013/05/cheapest-openflow-switch-in-world-using.html

9. Steve Roberts
Software

OpenFlow is attracting lots of Open Source
attention with lots of high quality free software
available.

My switch uses LINC from FlowForwarding

Why use LINC?

Free

Supports latest standards

I've been involved with it
http://openflow-sdn.blogspot.co.uk/2013/05/openflow-switch-on-raspberry-pi-part-2.html

10. Steve Roberts
LINC

Runs on Erlang

Easy to get Erlang running on Raspberry Pi

Download LINC from http://flowforwarding.org

Supports latest OpenFlow protocol (1.3)

Supports OpenFlow config protocol (OFC1.1)

11. Steve Roberts
Typical OpenFlow Architecture
OpenFlow
Switch
OpenFlow
Controller
Business Logic
(Controller or controllers)
(Applications eg Firewall)
OpenFlow
Switch
OpenFlow
Controller
This is what the
Raspberry Pi is
Doing – it's a switch

12. Steve Roberts
Now what?

An OpenFlow switch on it's own is useless

It does nothing without a controller

Possible to run controller software on the same
Raspberry Pi or somewhere else in the network

Lots of free OpenFlow controller software out
there.

13. Steve Roberts
OpenFlow Controllers

Recommend to use the following with LINC

Ryu (http://osrg.github.io/ryu/)

Trema (http://trema.github.io/trema/)

Why?

These support the latest OF1.3 protocol.

Most other controllers are not as current

Start with Ryu when using LINC. I haven't tried
Trema yet but it should work
http://openflow-sdn.blogspot.co.uk/2013/05/openflow-switch-on-raspberry-pi-part-3.html

14. Steve Roberts
What Next?

You can see more detail on how to build an
OpenFlow switch on my blog
http://openflow-sdn.blogspot.co.uk

I'm planning to write the controller for a WiFi access
point supporting user authentication and user based
routing

Port LINC to a RoutoBox

Feel free to contact me