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Customizable, Fast, Virtual Network Testbeds on Commodity Hardware

Customizable, Fast, Virtual Network Testbeds on Commodity Hardware. Nick Feamster Georgia Tech Murtaza Motiwala, Yogesh Mundada, Vytautas Valancius, Andy Bavier, Mark Huang, Larry Peterson, Jennifer Rexford. ?. VINI Overview.

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Customizable, Fast, Virtual Network Testbeds on Commodity Hardware

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  1. Customizable, Fast, Virtual Network Testbeds on Commodity Hardware Nick FeamsterGeorgia Tech Murtaza Motiwala, Yogesh Mundada, Vytautas Valancius,Andy Bavier, Mark Huang, Larry Peterson, Jennifer Rexford

  2. ? VINI Overview Bridge the gap between “lab experiments” and live experiments at scale. • Runs real routing software • Exposes realistic network conditions • Gives control over network events • Carries traffic on behalf of real users • Is shared among many experiments Emulation VINI Simulation Small-scale experiment Live deployment

  3. Traffic Synthetic or traces Real clients, servers Goal: Control and Realism Topology Arbitrary, emulated Actual network Traffic Synthetic or traces Real clients, servers • Control • Reproduce results • Methodically change or relax constraints • Realism • Long-running services attract real users • Connectivity to real Internet • Forward high traffic volumes (Gb/s) • Handle unexpected events Network Events Inject faults, anomalies Observed in operational network

  4. Overview • VINI characteristics • Fixed, shared infrastructure • Flexible network topology • Expose/inject network events • External connectivity and routing adjacencies • PL-VINI: prototype on PlanetLab • Preliminary Experiments • Ongoing work

  5. Fixed Infrastructure

  6. Shared Infrastructure

  7. Arbitrary Virtual Topologies

  8. Exposing and Injecting Failures

  9. c Carry Traffic for Real End Users s

  10. BGP BGP c BGP BGP Participate in Internet Routing s

  11. PL-VINI: Prototype on PlanetLab • First experiment: Internet In A Slice • XORP open-source routing protocol suite (NSDI ’05) • Click modular router (TOCS ’00, SOSP ’99) • Clarify issues that VINI must address • Unmodified routing software on a virtual topology • Forwarding packets at line speed • Illusion of dedicated hardware • Injection of faults and other events

  12. Node Mgr Local Admin VM1 VM2 VMn … Virtual Machine Monitor (VMM) (Linux++) PL-VINI: Prototype on PlanetLab • PlanetLab: testbed for planetary-scale services • Simultaneous experiments in separate VMs • Each has “root” in its own VM, can customize • Can reserve CPU, network capacity per VM PlanetLab node

  13. Version 2: Trellis

  14. Design Decisions • Container-based virtualization • Terminate tunnels with Ethernet GRE • Terminate tunnels in the root context • Use a “shortbridge” for point-to-point links

  15. Performance Evaluation • Packet forwarding rates comparable to directly terminating tunnels within the container.

  16. Challenges and Next Steps • Could have run experiments on Emulab • Goal: Operate our own virtual network • Want customizable packet forwarding • Must do this without compromising speed • We can tinker with routing protocols • Goal: Attracting real users • Require external connectivity (BGP Multiplexing)

  17. Conclusion • VINI: Controlled, Realistic Experimentation • Installing VINI nodes in NLR, Abilene • Download and run Internet In A Slice http://www.vini-veritas.net/

  18. XORP: Control Plane • BGP, OSPF, RIP, PIM-SM, IGMP/MLD • Goal: run real routing protocols on virtual network topologies XORP (routing protocols)

  19. User-Mode Linux: Environment • Interface ≈ network • PlanetLab limitation: • Slice cannot create new interfaces • Run routing software in UML environment • Create virtual network interfaces in UML UML XORP (routing protocols) eth0 eth1 eth2 eth3

  20. Click: Data Plane • Performance • Avoid UML overhead • Move to kernel, FPGA • Interfaces  tunnels • Click UDP tunnels correspond to UML network interfaces • Filters • “Fail a link” by blocking packets at tunnel UML XORP (routing protocols) eth0 eth1 eth2 eth3 Control Data Packet Forward Engine UmlSwitch element Tunnel table Click Filters

  21. Intra-domain Route Changes s 2095 856 700 260 233 1295 c 639 548 366 846 587 902 1893 1176

  22. Routes converging Link down Link up Ping During Link Failure

  23. Slow start Retransmit lost packet Close-Up of TCP Transfer PL-VINI enables a user-space virtual network to behave like a real network on PlanetLab

  24. Link down Link up Zoom in TCP Throughput

  25. Ongoing Work • Improving realism • Exposing network failures and changes in the underlying topology • Participating in routing with neighboring networks • Improving control • Better isolation • Experiment specification

  26. Resource Isolation • Issue: Forwarding packets in user space • PlanetLab sees heavy use • CPU load affects virtual network performance

  27. Performance is bad • User-space Click: ~200Mb/s forwarding

  28. VINI should use Xen

  29. Experimental Results • Is a VINI feasible? • Click in user-space: 200Mb/s forwarded • Latency and jitter comparable between network and IIAS on PL-VINI. • Say something about running on just PlanetLab? Don’t spend much time talking about CPU scheduling…

  30. Low latency for everyone? • PL-VINI provided IIAS with low latency by giving it high CPU scheduling priority

  31. XORP Run OSPF Configure FIB Click FIB Tunnels Inject faults OpenVPN & NAT Connect clients and servers C Internet In A Slice S S C S C

  32. UML XORP eth0 eth1 eth2 eth3 UmlSwitch Control Data FIB UmlSwitch element Encapsulation table Click tap0 PL-VINI / IIAS Router • Blue: topology • Virtual net devices • Tunnels • Red: routing and forwarding • Data traffic does not enter UML • Green: enter & exit IIAS overlay

  33. PL-VINI Summary

  34. PL-VINI / IIAS Router • XORP: control plane • UML: environment • Virtual interfaces • Click: data plane • Performance • Avoid UML overhead • Move to kernel, FPGA • Interfaces  tunnels • “Fail a link” UML XORP (routing protocols) eth0 eth1 eth2 eth3 Control Data Packet Forward Engine UmlSwitch element Tunnel table Click

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