Route Configuration

This repository is a lab for NCTU course "Introduction to Computer Networks 2018".

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Abstract

In this lab, we are going to write a Python program with Ryu SDN framework to build a simple software-defined network and compare the different between two forwarding rules.

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Objectives

1. Learn how to build a simple software-defined networking with Ryu SDN framework
2. Learn how to add forwarding rule into each OpenFlow switch

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Execution

TODO:

• How to run your program?
• What is the meaning of the executing command (both Mininet and Ryu controller)?
• Show the screenshot of using iPerf command in Mininet (both SimpleController.py and controller.py)

Run program

• open 2 terminals( t1 & t2 )
• first run SimpleTopo.py / topo.py in t1 by "mn --custom SimpleTopo.py / topo.py --topo topo -link tc --controller remote"
• then run SimpleController.py / controller.py in t2 by "ryu-manager SimpleController.py / controller.py --observe-links"
• use iperf command in t1 and get result
• leave t1 first, then leave t2

Meaning

Mininet

• --custom .py: read custom classes or params from .py file(s)
• --topo linear/minimal/reversed/single/torus/tree: linear=LinearTopo, torus=TorusTopo, tree=TreeTopo, single=SingleSwitchTopo, reversed=SingleSwitchReversedTopo, minimal=MinimalTopo
• -link default/ovs/tc: default=Link ovs=OVSLink tc=TCLink
• --controller default/none/nox/ovsc/ref/remote/ryu: ovsc=OVSController, none=NullController, remote=RemoteController, default=DefaultController, nox=NOX, ryu=Ryu, ref=Controller
• -c : clean up

Ryu controller

• ryu-manager: ryu-manager is the executable for Ryu applications. ryu-manager loads Ryu applications and run it.

• --observe-links: observe link discovery events.

• Screenshot of SimpleController

• Screenshot of controller

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Description

Tasks

TODO:

• Describe how you finish this work in detail

1. Environment Setup

• clone initial repository from github and login to container by SSH
• run Mininet with OvS's controller ( to support topos )

2. Example of Ryu SDN

• open 2 terminals(t1 & t2 )and both login to container
• both change directory to /src/
• first run SimpleTopo.py in t1 by "mn --custom SimpleTopo.py --topo topo -link tc --controller remote"
• then run SimpleController.py in t2 by "ryu-manager SimpleController.py --observe-links"

leave RYU controller way:

• first leave t1 by "exit"
• then leave t2 by Ctrl-z & "mn -c"

3. Mininet Topology

• duplicate SimpleTopo.py and change it name to topo.py by " cp SimpleTopo.py topo.py"
• change s1-s2 & s1-s3 & s2-s3 's bandwidth, delay, loss rate as follow
• go to task 5

4. Ryu Controller

• duplicate SimpleController.py and change it name to controller.py by " cp SimpleController.py controller.py"
• modify switch_features_handler(self, ev) part as follow rules
• go to task 5

5. Measurement
   for task 3(SimpleController):

• first run topo.py in t1 by "mn --custom topo.py --topo topo -link tc --controller remote"
• then run SimpleController.py in t2 by "ryu-manager SimpleController.py --observe-links"
• use iperf commands in t1:
  h1 iperf -s -u -i 1 -p 5566 > ./out/result1 &
  h2 iperf -c 10.0.0.1 -u -i 1 -p 5566
• then get result 1 (leave RYU controller)

for task 4(controller):

• first run topo.py in t1 by "mn --custom topo.py --topo topo -link tc --controller remote"
• then run controller.py in t2 by "ryu-manager controller.py --observe-links"
• use iperf commands in t1:
  h1 iperf -s -u -i 1 -p 5566 > ./out/result2 &
  h2 iperf -c 10.0.0.1 -u -i 1 -p 5566
• then get result 2 (leave RYU controller)

Discussion

TODO:

• Answer the following questions

1. Describe the difference between packet-in and packet-out in detail.
   packet-in: 由switch發出，請求controller
   packet-out: 由controller發出，告知switch將packet導致對應主機

2. What is “table-miss” in SDN?
   假如一個封包在Flow Table裡?有發現能夠匹配成功的Flow Entry，這就是一次"Table Miss"。
   至於發生Table Miss後的動作取決于此Flow Table的配置：
   1）直接丟棄，2）繼續轉發給後面的Flow Table，3）封裝成 packet-in 消息送給Remote Controller。

3. Why is "(app_manager.RyuApp)" adding after the declaration of class in controller.py?
   讓class繼承 app_manager.RyuApp。 app_manager.RyuApp是Ryu應用程式的基礎類別

4. Explain the following code in controller.py.

   @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)

@set_ev_cls(ev_cls, dispatchers=none) 是一個用於將方法註冊成 Ryu 事件處理器的一個修飾器，被修飾的方法將會成為一個事件處理器。
ev_cls 表示想要被該 Ryu 應用程式接收的事件類別。
dispatchers 則表示了該事件處理器將會在哪些談判階段（negotiation phases） 去接收此一類型的事件
MAIN_DISPATCHER: 接收 Switch-features 訊息以及 傳送 set-config 訊息

5. What is the meaning of “datapath” in controller.py?
   the switch in the topology using OpenFlow

6. Why need to set "ip_proto=17" in the flow entry?
   定義該封包資料區使用的協定，17 代表UDP

7. Compare the differences between the iPerf results of SimpleController.py and controller.py in detail.
   Simple: 10sec 1.21MB 1.01 Mb/s 0.005ms 32/893(3.6%)
   control: 10sec 1.23MB 1.03Mb/s 0.006ms 18/893(2%)

8. Which forwarding rule is better? Why?
   lost: simplecontroller > controller

controller is better.

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References

TODO:

• Please add your references in the following

• Ryu SDN
  • Ryubook Documentation
  • Ryubook [PDF]
  • Ryu 4.30 Documentation
  • Ryu Controller Tutorial
  • OpenFlow 1.3 Switch Specification
  • Ryubook 說明文件
  • GitHub - Ryu Controller 教學專案
  • Ryu SDN 指南 – Pengfei Ni
  • OpenFlow 通訊協定
• Python
  • Python 2.7.15 Standard Library
  • Python Tutorial - Tutorialspoint
• Others
  • Cheat Sheet of Markdown Syntax
  • Vim Tutorial – Tutorialspoint
  • 鳥哥的 Linux 私房菜 – 第九章、vim 程式編輯器

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Contributors

TODO:

• Please replace "YOUR_NAME" and "YOUR_GITHUB_LINK" into yours

• 吳宜珈
• David Lu

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License

GNU GENERAL PUBLIC LICENSE Version 3