high-fidelity switch models for sdn emulation
DESCRIPTION
High-Fidelity Switch Models for SDN Emulation . Danny Y. Huang Kenneth Yocum Alex C. Snoeren University of California, San Diego. Buying OpenFlow Switches. Clients. Which one to buy?. HP Procurve Fulcrum Monaco Quanta LB4G. Buying OpenFlow Switches. 30% queries timed out. Clients. - PowerPoint PPT PresentationTRANSCRIPT
High-Fidelity Switch Models for SDN Emulation
Danny Y. HuangKenneth YocumAlex C. Snoeren
University of California, San Diego
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Which one to buy?
Buying OpenFlow SwitchesClients
HP Procurve
Fulcrum Monaco
Quanta LB4G
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Buying OpenFlow SwitchesClients
30% queries timed out
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Buying OpenFlow SwitchesClients
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Buying OpenFlow SwitchesClients
Same topology. Same workload.
Different performance!
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Buying OpenFlow SwitchesPerformance Variations
x 1,000 =
Clients
How to predict the performance?
Which one to buy?
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Emulating OpenFlow Networks
Controller
OpenFlow
Data Traffic Data Plane
Simulators / Emulators
Control PlaneOpen vSwitch
Mininet
OVS itself would also introduce performance variations.
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Problem
Hard to predict OpenFlow network’s performance:
• OpenFlow Switches are different.
• Existing emulation framework is not good enough.
Goal
To predict performance with realism:
• To design an emulator that captures vendor variations.
• To measure these variations in the control plane.
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Variations across Vendors
Controller
OpenFlowProtocol
Data Traffic
Differences in Control Plane
Flow table size
Flow management policies
Switch CPU
etc
Focus on CPU’s effect on control-path delays.
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Control-Path Delays
Hardware OpenFlow
Switch
Controller (POX)
Application Workload
Ingress
Packet-inEvents
Flow-modEvents
EgressData plane traffic
Ingress Delay
Egress Delay
TCAM
CPU
Disproportionately affects short flows.
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Measure Control-Path Delays
Server
Eth 0
Eth 1
Eth 2
OF Switch
Data Plane
Control PlaneController
Clients
HP Procurve
Fulcrum Monaco
Quanta LB4G
Open vSwitch (OVS)
Installs rules for every new flow
Queries for a 64-byte value every 50 ms. We measure the query time, ingress & egress delays.
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Measure Redis Query Times
Query completion times for Redis clients (ms)
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Measure Ingress DelayOVS faster than
the others.
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Measure Egress Delay
Slow down the ingress and egress delays on OVS to emulate the hardware
OVS: almost no delays!
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Implementing the Emulator
Open vSwitch (OVS)
Application Workload
Ingress
Packet-in Events
Data plane traffic
Controller (POX)
Flow-mod Events
Egress
To slow down control traffic
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Emulator Proxy
Open vSwitch (OVS)
Emulator Proxy
Application Workload
Ingress
Packet-in Events
Data plane traffic
Controller (POX)Packet-in Events
(Delayed)
Flow-mod Events(Delayed)
Egress
Flow-mod Events Physical OF Switch≈
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Evaluation
Query completion time for Redis clients (ms)
CDF
HP
OVS
Hardware
Emulated
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Query completion time for Redis clients (ms)
Evaluation
CDF
Query completion time for Redis clients (ms)
HP
Monaco
OVS
Hardware
Emulated
• We emulate the ingress and egress delays only.
• Reasonble approximation.
Query completion time for Redis clients (ms)
Quanta
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Summary
• Hard to predict performance due to vendor variations.
• We designed an emulator for control-path delays.
• Simple, but achieves reasonable approximation.
Future Work
• Increase realism. Capture more artifacts.
• Expand workload coverage. Automate switch measurements.
• Capture interactions among multiple switches.
Acknowledgements Marco Canini and Dan Levin (TU Berlin)George Porter (UC San Diego)
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Thank you!
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Inverse Transform Sampling
• Goal: Emulate switch X, which introduces ingress delay t with probability p.
• Algorithm:1. Measure the delay distributions of OVS and X. Make
them into tables.2. Measure how much OVS has delayed. Call this tOVS.3. Look up tOVS from the OVS table. This returns probability
p.4. Look up p from X’s table. This returns delay tX.5. Introduce delay (tX - tOVS).
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Evaluation (QQ Plots)
HP Monaco Quanta
Tim
e on
Em
ulat
or (m
s)
Query completion time on hardware switches (ms)
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Time Dilation