open flow protocol
TRANSCRIPT
Computer Network : set of computers connected together for the purpose of
sharing resources
Software-defined networking (SDN) : Approach to allow network
administrators to programmatically initialize, control, change, and manage
network behavior dynamically
Network Switch : connects devices together using packet switching
Hub : common connection point for devices in a network,used to connect segments
of a LAN
Router : forwards data packets between computer networks
Current Internet Closed to Innovations in the Infrastructure
n
n
Specialized Packet Forwarding Hardware
n
Specialized Packet Forwarding Hardware
“Software Defined Networking”approach to open it
Network Operating System
App App App
n
n
Specialized Packet Forwarding Hardware
n
Specialized Packet Forwarding Hardware
The “Software-defined Network”
Network Operating System
App App App
3.Well Defined Open API
2. At least one good operating systemExtensible, possibly open-source
Simple PacketForwardingHardware
Simple PacketForwardingHardware
Simple PacketForwardingHardware
1. Open interface to hardware
OpenFlow - Defintion
• enabler of SDN
• first standard communication interface defined between the
control and forwarding layers of SDN Architecture
• needed to move network control out of proprietary network
switches into control software that's open source
• mainly used between switch and controller as a secure channel
• layered on top of the Transmission Control Protocol(TCP)
• controllers listen on TCP port 6653 for the switches to connect
Data Path (Hardware)
Control Path OpenFlow
OpenFlow Controller
OpenFlow Protocol (SSL/TCP)
Components of OpenFlow Network
OpenFlow Controller
Manages one or more switch via OpenFlow channels
Uses OpenFlow protocol to communicate with a OpenFlow aware
switch
OpenFlow Channel
Used to exchange OpenFlow message between switch and controller
OpenFlow Switch
Consists of one or more flow tables,group table and meter table
Single switch can be manages by one or more controllers
Flow tables and group tables are used during the lookup or forwading
phase
Meter table is used to perform simple QOS operations
OpenFlow Basics
SwitchPort
MACsrc
MACdst
Ethtype
VLANID
IPSrc
IPDst
IPProt
L4sport
L4dport
Rule
+ mask what fields to match10
VLANpcp
IPToS
Flow entries : instructions that tell an openflow switch what to do with an incoming
stream of packets and the are stored in the flow table
Operating Modes
Reactive
• First packet of flow triggers
controller to insert flow entries
• Efficient use of flow table
• Every flow incurs small additional
flow setup time
• If control connection lost, switch
has limited utility
Proactive
•Controller pre-populates flow table in
switch
•Essentially requires aggregated
(wildcard) rules
•Zero additional flow setup time
•Loss of control connection does not
disrupt traffic
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Reactive vs. Proactive (pre-populated)
Both models are possible with OpenFlow
Centralized Control
OpenFlowSwitch
OpenFlowSwitch
OpenFlowSwitch
Controller
Distributed Control
OpenFlowSwitch
OpenFlowSwitch
OpenFlowSwitch
Controller
Controller
Controller
Centralized vs Distributed Control
Both models are possible with OpenFlow
Control Modes
Flow Routing vs. AggregationBoth models are possible with OpenFlow
Flow-Based
• Every flow is individually
set up by controller
• Exact-match flow entries
• Flow table contains one
entry per flow
• Good for fine grain
control, e.g. campus
networks
Aggregated
•One flow entry covers large
groups of flows
•Wildcard flow entries
•Flow table contains one
entry per category of flows
•Good for large number of
flows, e.g. backbone
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Simple Packet Forwarding Hardware
Network Operating System 1
Open interface to hardware
Virtualization or “Slicing” Layer
Network Operating System 2
Network Operating System 3
Network Operating System 4
App App App App App App App App
Many operating systems, orMany versions
Open interface to hardware
Isolated “slices”
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Virtualizing
OpenFlow
Summary
• OpenFlow/SDN is evolving to facilitate an ecosystem for innovation
• OpenFlow is being deployed in over 100 organizations world-wide
– GEC9 in Nov, 2010 showcased nation-wide OF
– Internet 2 and NLR starting to serve as the GENI Backbone
• OpenFlow is essential for Service Providers
– Custom control for Traffic Engineering
– Combined Packet/Circuit switched networks
Are you innovating in your
network?