Tutorial: OpenFlow-Based
Vertical Handoff over WiFi and
WiMAX in the Orbit Testbed
Ryan Izard and KC Wang
Clemson University
GEC18
Sponsored by the National Science Foundation
Tutorial Objectives
• The tutorial covers step-by-step how to use OpenFlow to
experiment with mobile device handoff across two
wireless networks (Wi-Fi and WiMAX) in ORBIT
• Key objectives:
– Learn how SDN enables a range of possibilities for your
research
– Learn multiple ways to program your network
• Ingredients:
–
–
–
–
Linux network interface bridging (tap and bridge)
Open vswitch (OVS)
Floodlight OpenFlow controller
Perl and bash scripting
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Mobile Handoff
Application server
Net A
Provider A
OF controller
OpenFlow tunnel
Net B
Net C
Provider B
OF controller (or non-OF)
Net D
Provider A
or partner’s
OF controller
Provider A
or partner’s
OF controller
Client M
• From reactive to proactive networking
– Mobile IP: Distributed, reactive (long latency), requires
compatible agents everywhere, provider-dictated
– OpenFlow: Centralized, proactive, solutions for diverse network
scenarios, opportunities for both provider and client
customization
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Components and Skills You Can Use
Later
• I just want to connect to WiMAX
– Also talk to us about SciWiNet, another project for you to use
commercial (Sprint) wireless network for research
• I want to experiment with my research on mobile apps,
with mobile device repeatedly handing off between two
networks, static or mobile
– We plan to put a WiMAX mobile on a campus shuttle, details TBD
• I want to develop a better OpenFlow-based handoff
solution
– Program OpenFlow controller
• I want to use the OpenFlow flow pusher in other OpenFlow
networks or devices.
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Deployment Map
• Greenville subnet
– covers I-85, I-385, Woodruff shopping district
– campus hourly shuttle route
• Clemson subnet
– covers campus and part of Clemson downtown
Clemson
Greenville
One BS
only
BS1
CU-ICAR campus
BS2
Hotel
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Commercial Clemson
Downtown
District
GREESC13
GENI BS1
Fluor Daniel
GENI BS2
Clemson House
5
Clemson Coverage Plan – One Sector
Clemson
-ICAR
shuttle
route
BS1
Byrnes Hall
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Greenville Coverage Plan – Two Sectors
Clemson
-ICAR
shuttle
route
BS1, BS2
CU-ICAR campus
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Now the fun begins.
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• Part I: Design/Setup
– Experiment Overview
– Configure scripts for experiment
• Part II: Execute
– Execute handoff experiment
• Part III: Finish
– Determine results
– Shutdown nodes
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• Part I: Design/Setup
– Experiment Overview
– Configure scripts for experiment
• Part II: Execute
– Execute handoff experiment
• Part III: Finish
– Shutdown nodes
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Setup Experiment / Configure Scripts
Experiment is a simple ping to show handoff between
WiFi and WiMAX in the Orbit grid testbed:
1) Login to your client node. (The server and AP are preconfigured for you.)
2) Configure Floodlight.
3) Get WiMAX and WiFi interface HW information.
4) Configure startup script.
5) Configure interface-switching scripts.
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• Part I: Design/Setup
– Experiment Overview
– Configure scripts for experiment
• Part II: Execute
– Execute handoff experiment
• Part III: Finish
– Shutdown nodes
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Execute Experiment
Experiment is a simple ping to show handoff between
WiFi and WiMAX in the Orbit grid testbed:
1) WiFi flows are installed as “initial flows” when setup
script is run.
2) Start a ping to the server IP. The packets will be
switched out the WiFi interface.
3) Run the WiMAX switching script. The ping packets will
be switched out the WiMAX interface.
4) You’ve performed a handoff! Want proof? View the
flows and packet counts on each OVS bridge before
and after an interface-switch.
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• Part I: Design/Setup
– Experiment Overview
– Configure scripts for experiment
• Part II: Execute
– Execute handoff experiment
• Part III: Finish
– Shutdown nodes
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Teardown Experiment
When the experiment is done:
Exit SSH session to Orbit image. I will take the
nodes down after the experiment.
When experimenting on your own, you may save
and modify your Oribit images for future
experiments.
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