This document describes a student project to implement a software-defined network load balancer using the POX controller. It is divided into two parts: the first part analyzes the POX controller and its OpenFlow module, explaining components like the libopenflow library and discovery module. The second part details the development of a load balancer using a round-robin algorithm to distribute traffic across multiple servers, including modifications made to the POX code and testing in a Mininet environment to analyze performance.

1. Final Project
Load Balancer Using Software-Defined Network - POX
Team Group 4
7-Dec 2015
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Group Name SJSU ID Class ID Roles
Group member 1 Avanish Gupta 010129847 22 Code analysis and debug
Group member 2 Kunal Goswami 010772541 20 Code analysis and debug
Group member 3 Ayush Sharma 010034141 71 Design, code and implement
Group member 4 Ikwhan Chang 010754107 9 Design, code and test

2. INDEX
• Part1: SDN Analysis
• POX Controller: OpenFlow
• OpenFlow Startup events
• OpenFlow Module
• Flow of Control
• Components
• Part2: Development
• Introduction
• Modifications
• Test CDN Environments
• Performance Analysis
• Architecture & Topology
• Demo
• Q&A
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3. Part 1:
SDN
Analysis
• POX Controller: OpenFlow
• POX Startup events.
• OpenFlow Module
• Flow of Control
• Components
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4. POX Controller:
OpenFlow
• POX is an open source controller developed in
python language for software defined
networking.
• For the part 1 of our project, we have chosen
the OpenFlow module for our analysis. The
following image shows the important
components of the OpenFlow module.
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5. 5
POX startup events

6. OpenFlow Module
• In the accompanying diagram, we go through
the outline of the OpenFlow module.
• The discovery and keep alive components of
OpenFlow provide input to the topology
module so as to create and manipulate the
network topology.
• The libopenflow module communicates with
the lib.packet module in order to handle the
packets as well as the events that are fired
through the network.
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7. Flow of Control
• The flow of control in POX controller can be understood as an
outline of the actual flow.
• We consider the outline/overview for the POX controller flow
because of the interdependency between the modules in it.
• There are well defined classes and events for every single event that
occurs in a network, however they’re utilized by multiple components
of the POX controller and the flow of control keeps jumping from one
component to another.
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8. Flow of control
• The startup of the POX controller transfers the control from the main
“pox.py” to openflow/libopenflow component of POX.
• This file contains the events for the packets that are transferred
amongst the switches.
• The topology is updated simultaneously with the discovery
component and the topology component of the POX controller.
• We now discuss the important components of the OpenFlow module
in POX.
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9. Component: libopenflow
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• This file contains the definition
of various classes and
constants such as the
openflow messages in the
specification, the methods
which deal with the statistics of
the packets exchanged.
• This module is called by the
main execution script, pox at
the startup as well as it is
continuously in scope while
checking the topology and
manipulating it.
• Corresponding diagram shows
the example of one such class.

10. Component: of_01
• The name of_01 denotes the version of the openflow protocol that
POX supports, that is version 01.
• This component deals with the switches with events like
connectionUp, connectionDown, portStatus etc. It informs the user
about the topology, whether or not a switch is connected to the
network.
• All the communication from the controller to the switches goes
through this code, the messages that are sent, the statistics that are
received from the switches. These messages can be displayed with
the help of the logger available in POX.
• The unpacked information that is available from the libopenflow
module, which is received from the packets that are exchanged is
used in this component to send different requests such as HELLO,
ECHO, FLOW_REMOVED etc.
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11. Component: Discovery
• The discovery component in openflow deals with the discovery of
the nodes in the network. The switches as well as the hosts, this
component then communicates with the topology component in
Openflow module.
• The topology component acts like a bridge between POX’s topology
module and Openflow module and helps the controller to set up and
manipulate the network topology.
• This module communicates with the flow table as well to determine
the flow rules for the switches, it updates the flow rules as well as
discovers them upon startup.
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12. Difficulties faced
• The very first obstacle that lied on our path was the interdependency
of the python modules with each other. We solved it using line by
line execution with the help of pdb.set_trace() from the python
debugger.
• Determining the flow of control in the openflow module wasn’t easy,
for the same purpose we referred the API calls from one function to
another in order to check the flow of control manually.
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13. Part 2: Load
Balancing in
SDN
• Introduction
• Modifications
• Test CDN Environments
• Performance Analysis
• Architecture & Topology
• Demo
• Q&A
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14. Introduction
• Project Goals
• POX is a popular Python based open source SDN controller with the help of which we can easily check the
configuration of a customized networking environment.
• Our project will easily setup the CDN(Content-Delivery Network) environments using POX loadbalancer
• The POX loadbalancer is modified by our team using Round-Robin Algorithm(prev: Random Select)
• What is CDN?
• A large distributed system of proxy servers deployed in multiple data centers via the Internet.
• Project Requirements
• SDN Controller: POX
• Language: Python 1.7 based on POX controller
• Topology/VM: Mininet VM Seed
• WAS: Node.js / Express.js
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(Left) Single server distribution
(Right) CDN scheme of distribution

15. • Select the server(self._pick_server())
• Set up the table entry towards selected
server
• Set up Openflow actions using selected
server’s ip/mac
• Set up Openflow match based on request
packet(packet, inport)
• Set up the open flow’s message using
customised action/match
• Send message using OpenFlow
Load Balancer Algorithms
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16. Modifications
• Default LB: Random Selection
• /pox/misc/ip_loadbalancer.py
line(193~197)
• Implemented simple random selection.
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• Modified: Round Robin Selection
• /pox/misc/loadbalancer_cmpe207.py
• Add the get_next_server() in order to get the index based on
round robin
• If there is live server(self.live_servers), get_next_server() will
pick the live server and then return in order to connect the
client’s requests.

17. Load Balancer Algorithms
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sudo mn --arp --topo single,5 --mac --switch ovsk --controller remote -x

18. Test Environments
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Server: index.js
Running on 10.0.0.1/10.0.0.2/10.0.0.3/10.0.0.4
Client: Ajax Requestwith AngularJS
Static
Resources:
Client: HTML View

19. Test Environments
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1. Running LB on 10.0.0.254
2. Run Server Application into each servers
3. Connect client’s web page using Firefox

20. Test Environments
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1. Set the # of image from server
2. LB will separate the packet into each servers
3. The static resource will be requested by each servers.
4. Images are loaded

21. Test Environments
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22. Performance Analysis
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0 4 8 12 16
5
10
20
50
Response Time(sec)
HTTPRequest#
Random R-R

23. Demo
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https://www.youtube.com/watch?v=1_1hJZFYn_E

24. Conclusion
• SDN works as cutting-edge technologies of Network Virtualization
• Modified load balancer module to perform round robin scheduling
• Improved the performance of web resources from servers
• Showed the improved results in terms of fetching image from the servers
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25. Q & A 25

26. Thanks! 26
SJSU Fall-2015 CMPE207 Group 4 Final Project Presentation