An Overview of OpenFlow
Andrew Williams
Agenda
• What is OpenFlow?
• OpenFlow-enabled Projects
• Plans for a large-scale OpenFlow deployment
through GENI
• OpenFlow at N.C. State
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Agenda
• What is OpenFlow?
• OpenFlow-enabled Projects
• Plans for a large-scale OpenFlow deployment
through GENI
• OpenFlow at N.C. State
2
A problem for researchers
• I’ve created a new routing algorithm, how can I test it
out?
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What is OpenFlow?
• Switching specification
that decouples a
switches Control plane
from it’s Data plane
http://www.openflow.org/documents/openflow-wp-latest.pdf
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How does it work?
• Uses flow-based routing rules stored in an
OpenFlow-Enabled switch’s memory to successful
forward incoming packets
• When a packet comes in that isn’t part of a flow, it
is sent to the Controller
• Controller decides what to do with the packet/flow
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Matching packets at the Switch
• Incoming packets can be matched with flows based
on:
• Ingress Port, Ether src, Ether dst, Ether type, VLAN id,
VLAN priority, IPv4 src, IPv4 dst, TCP/UDP/SCTP src,
TCP/UDP/SCTP dst, …
• Over 15 potential values defined in the OpenFlow
1.1.0 standard!
http://www.openflow.org/documents/openflow-spec-v1.1.0.pdf
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Main Benefit
• A researcher can have full control of the control
plane without giving up the speed at which the
hardware forwards packets
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OpenFlow-Enabled Switches
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Cisco Catalyst 6K series
Cisco Catalyst 3750
Juniper MX series
HP ProCurve 5400zl series and ProCurve 6600 series
Arista 7100 series
Pronto 3290 and 2780,
NEC IP8800
Ciena CoreDirector Circuit Switch
Dell and IBM rumored to be interested in OpenFlow
http://groups.geni.net/geni/attachment/wiki/SpiralTwo/GENIS2Ovrvw060310.pdf
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Agenda
• What is OpenFlow?
• OpenFlow-enabled Projects
• Plans for a large-scale OpenFlow deployment
through GENI
• OpenFlow at N.C. State
9
OpenFlow enabled projects
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FlowVisor - Dividing network resources into "slices“
Load balancing
PhoneNet – Direct Phone to Phone communication
Deploying in-network services (caching, firewall, etc.)
Turning an OpenFlow-enabled switch into an MPLS
switch
• Many more!
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Agenda
• What is OpenFlow?
• OpenFlow-enabled Projects
• Plans for a large-scale OpenFlow deployment
through GENI
• OpenFlow at N.C. State
11
Also: Kansas State University, Internet2, and the National Lambda Rail
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Bringing everything together
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Agenda
• What is OpenFlow?
• OpenFlow-enabled Projects
• Plans for a large-scale OpenFlow deployment
through GENI
• OpenFlow at N.C. State
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OpenFlow @ N.C. State
• RENCI, N.C. State, and the other nearby universities
recently received 5 OpenFlow-Enabled switches
• RENCI has worked previously with GENI expanding its
test bed offerings.
http://www.csc.ncsu.edu/news/1132
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Let’s Discuss

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Performance Issues
• “Preliminary results suggested that an Ethane
controller based on a low-cost desktop PC could
process over 10,000 new flows per second — enough
for a large college campus.”
• Have been alternatives proposed to address this issue
– Pre-configuring routes before traffic is seen
– A more hybrid approach - DIFANE
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DIFANE
-Keeps packets travelling quickly in the network
http://www.cs.princeton.edu/~minlanyu/writeup/difane10-TR.pdf
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Ethane
• Precursor to OpenFlow
• Outlined the ideas behind OpenFlow but didn’t get
vendors to integrate into their own products.
• Limited to:
– Ethane Wireless Access Point (WRTSL54GS wireless router
running OpenWRT)
– Ethane 4-port Gigabit Ethernet Switch (NetFPGA based)
– Ethane 4-port Gigabit Ethernet Switch (Software
implementation powered by a computer)
http://yuba.stanford.edu/~casado/ethane-sigcomm07.pdf
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• http://www.openflow.org/downloads/technicalrepor
ts/openflow-tr-2009-1-flowvisor.pdf
• http://conferences.sigcomm.org/sigcomm/2009/de
mos/sigcomm-pd-2009-final26.pdf
• http://mobisocial.stanford.edu/papers/held09khuang.pdf
• http://portal.acm.org/ft_gateway.cfm?id=1851262&t
ype=pdf&CFID=15023189&CFTOKEN=46872270
• http://www.openflow.org/wk/index.php/OpenFlow
MPLS
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