Ryu controller - deal with openflow packets notes

- Controller receives a  packet from a switch if the switch failed to look up it's flow table
- Get incoming packet message, src mac/ip, dst mac/ip, ofproto, ... whatever you want
- Learn a switch-port-mac_address entry

Packets received in Ryu controller

- Use ryu as remote controller to listen packet_in event which is usually triggered when a open virtual switch failed to look up an legal entry in the flow table.
- Here are some packet examples sending from ovs:

Disable ipv6

- When starting mininet with arbitrary topology by using ryu as a remote controller, there are plenty of packets sends from each hosts to a set of strange mac addresses start with 33:33:XX:XX...

- I didn't send these pkts (they started sending immediately after mininet network was set up), and I didn't want they show up. These irritating messages kept refreshing the controller console and led to debug trouble.

Ryu -- Mininet Sample: k=4 Fat Tree

- Start Ryu manager (optional:with GUI needed files)

ryu-manager --verbose --observe-links ryu.app.simple_switch ryu.app.rest_topology  ryu.app.ofctl_rest ryu.topology.switches

Ryu - Installation

- Ryu is a SDN controller platform which supports OpenFlow. See also: http://osrg.github.io/ryu/

- By https://github.com/mininet/openflow-tutorial/wiki/Create-a-Learning-Switch#Controller_Choice_Ryu_Python, python-gevent, python-routes, python-webob, and python-paramiko should be installed.

Mininet - FatTree Topology

- Fat tree topology: https://en.wikipedia.org/wiki/Fat_tree

- If there is a loop in the topology, the hosts cannot ping the others because https://github.com/mininet/mininet/wiki/FAQ#ethernet-loops

Mininet OpenFlow Tutorial - Learn Development Tools

https://github.com/mininet/openflow-tutorial/wiki

- Start with a topology with 3 hosts and 1 switch (and 1 controller)

• "sudo mn --topo single,3 --mac --switch ovsk --controller remote"
• --switch ovsk: Open vSwitch 
• --mac: set the MAC address to hosts' IP address

Ubuntu: Network Interface named "eno16777736"

Source: http://blog.csdn.net/a549569635/article/details/49968189

Try to modify it as "eth0"

Mininet Walkthrough

See also: http://mininet.org/walkthrough/

- Start wireshark:

• "sudo wireshark &", an error message showed up: "Lua: Error during loading: dofile has been disabled due to running wireshark as superuser..."
• Seems everybody tried to stop me to run run wireshark as root.

Mininet Installation

See also: http://mininet.org/download/

- There are four methods to install Mininet.
  Option 1: Mininet VM Installation (easy, recommended)
  Option 2: Native Installation from Source
  Option 3: Installation from Packages
  Option 4. Upgrading an existing Mininet Installation
- I already have a new-installed Ubuntu virtual machine, so I choose option 2. ( ubuntu version Ubuntu 15.10)

Simulator VS Emulator

According to Wikipedia, "'emulation' referred only to emulation with a hardware or microcode assist, while 'simulation' referred to pure software emulation."

Python Challenge level 19

http://www.pythonchallenge.com/pc/hex/bin.html (login:butter/fly)

- A map of India. An email with an attachment (wav file). Very straightforward, we should convert the mess in the attachment into a voice file.

Python Challenge level 18

http://www.pythonchallenge.com/pc/return/balloons.html (logib:huge/file)

- Two picture, one is brighter. "Can you tell the difference?" and a comment says it's more easy than I think.
- Just visit http://www.pythonchallenge.com/pc/return/brightness.html and you will see the same page.....wait! The comment changes..."maybe consider deltas.gz"!

Python Challenge level 17

http://www.pythonchallenge.com/pc/return/romance.html (login:huge/file)

- A plenty of cookies. There is also a small picture on the lower left corner, remember it? It's the same photo as level 4. (I don't remember. Really.)
- Obviously, we should find out the cookies sent by level 4 webpage.

Python Challenge level 16

http://www.pythonchallenge.com/pc/return/mozart.html (login: huge/file)

- Only a meaning less image. A title refers that "let me get this straight", so maybe I need to find something NOT straight ... this picture?

- Observe that there are many pink segments in this picture.