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High-Fidelity Switch Models for SDN Emulation Danny Y. Huang Kenneth Yocum Alex C. Snoeren University of California, San Diego.

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Presentation on theme: "High-Fidelity Switch Models for SDN Emulation Danny Y. Huang Kenneth Yocum Alex C. Snoeren University of California, San Diego."— Presentation transcript:

1 High-Fidelity Switch Models for SDN Emulation Danny Y. Huang Kenneth Yocum Alex C. Snoeren University of California, San Diego

2 Which one to buy? Buying OpenFlow Switches 2 Clients HP Procurve Fulcrum Monaco Quanta LB4G

3 Buying OpenFlow Switches 3 Clients 30% queries timed out

4 Buying OpenFlow Switches 4 Clients

5 Buying OpenFlow Switches 5 Clients Same topology. Same workload. Different performance! Same topology. Same workload. Different performance!

6 Buying OpenFlow Switches 6 Performance Variations x 1,000 = Clients How to predict the performance? Which one to buy? How to predict the performance? Which one to buy?

7 Emulating OpenFlow Networks 7 Controller OpenFlow Data Traffic Data Plane Simulators / Emulators Control Plane Open vSwitch Mininet OVS itself would also introduce performance variations.

8 Problem Hard to predict OpenFlow networks performance: OpenFlow Switches are different. Existing emulation framework is not good enough. Problem Hard to predict OpenFlow networks 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. Goal To predict performance with realism: To design an emulator that captures vendor variations. To measure these variations in the control plane. 8

9 Variations across Vendors 9 Controller OpenFlow Protocol Data Traffic Differences in Control Plane Flow table size Flow management policies Switch CPU etc Differences in Control Plane Flow table size Flow management policies Switch CPU etc Focus on CPUs effect on control-path delays.

10 Control-Path Delays 10 Hardware OpenFlow Switch Hardware OpenFlow Switch Controller (POX) Application Workload Ingress Packet-in Events Flow-mod Events Egress Data plane traffic Ingress Delay Egress Delay TCAM CPU Disproportionately affects short flows.

11 Measure Control-Path Delays 11 Server Eth 0 Eth 1 Eth 2 OF Switch Data Plane Control Plane Controller 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.

12 Measure Redis Query Times 12 Query completion times for Redis clients (ms)

13 Measure Ingress Delay 13 OVS faster than the others.

14 Measure Egress Delay 14 Slow down the ingress and egress delays on OVS to emulate the hardware OVS: almost no delays!

15 Implementing the Emulator 15 Open vSwitch (OVS) Application Workload Ingress Packet-in Events Data plane traffic Controller (POX) Flow-mod Events Egress To slow down control traffic

16 Emulator Proxy 16 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

17 Evaluation 17 Query completion time for Redis clients (ms) CDF HP OVS Hardware Emulated

18 Query completion time for Redis clients (ms) Evaluation 18 CDF Query completion time for Redis clients (ms) HP Monaco OVS Hardware Emulated We emulate the ingress and egress delays only. Reasonble approximation. We emulate the ingress and egress delays only. Reasonble approximation. Query completion time for Redis clients (ms) Quanta

19 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. 19 Acknowledgements Marco Canini and Dan Levin (TU Berlin) George Porter (UC San Diego)

20 Thank you! 20

21 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 t OVS. 3.Look up t OVS from the OVS table. This returns probability p. 4.Look up p from Xs table. This returns delay t X. 5.Introduce delay (t X - t OVS ). 21

22 Evaluation (QQ Plots) 22 HP Monaco Quanta Time on Emulator (ms) Query completion time on hardware switches (ms)

23 Time Dilation 23


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