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Deploying Wifi on Lampposts

Deploying Wifi on Lampposts. The Ozone way…. Nicolas MECHIN Ozone EU-Mesh’s Heraklion meeting 07/08. Playground. « free » access to lampposts in Paris city center Permanent power available Aesthetic constraints Devices deployed need to be very discrete

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Deploying Wifi on Lampposts

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  1. Deploying Wifi on Lampposts The Ozone way… Nicolas MECHIN Ozone EU-Mesh’s Heraklion meeting 07/08

  2. Playground • « free » access to lampposts in Paris city center • Permanent power available • Aesthetic constraints • Devices deployed need to be very discrete • No big directionnals or patch antennas… • No land lines for internet backhaul • Backhaul through Ozone’s wireless 5GHz network • Idea is to offer seamless wifi roaming (sort of…) within the coverage area

  3. Area to be covered 1,4 km long

  4. Architecture Lamppost n+1 Lamppost n Radio Link Radio Link Ethernet POE POE 220 V Powerlines About 100 m OZONE Lamppost n+2…

  5. Hardware • Mikrotik RB532 • MIPS architecture • 3 Mini-PCI slots • 3 * CM9 wifi cards • Atheros chipset • Dual-band antennas • 4,5 dB @ 2.4GHz • 7 dB @ 5GHz

  6. What it looks like

  7. Actual Deployment • 10 LampPosts • 4 directly connected to Ozone’s network • 6 through other lamppost • All links use 5 GHz (5480 Hz – 5700 Hz) • 3 different connecting point to ozone’s 5GHz network

  8. Actual Deployment 500 m 730 m

  9. Coverage achieved • Over 160 000 m² covered

  10. Coverage achieved

  11. Coverage achieved • Focus on the « Hotel de Ville » area • « seamless » wifi mobility within this area • 14 000 m²

  12. First impressionscf. EU-MESH Benefits and Performance Metrics • Low cost deployment : Yes • Wireless backhaul : no heavy cost for deploying fixed lines • Relatively cheap hardware • 200 € / AP (all included) • Still have to climb the lamppost… • Fast deployment : Not so much • we missed easy to use tools to know whether the signal was good enough, what was the best position for antennas. Mass deployment not ready • Radio settings and IP addressing had no be prepared • Reliability, flexibility, reliability ...No • Static routing and static radio configuration • No self healing…

  13. First impressionscf. EU-MESH Benefits and Performance Metrics • EU-Mesh should provide us with an answer to these shortcomings • Easy deployment : auto-configuration, tools for controlling radio signal at deployment • Considering « low skills » technicians are to deploy the network • Mesh technologies can provide self healing networks • Wheread today we have a static network with static radio configuration, static IP adressing and routing…

  14. Tests planned • Performances of radio backhaul • Performances of inter lamppost radio hops • Considering « dedicated » radio interface and not single radio scenario • Throughput • RTTs

  15. ResultsFocus on radio performances

  16. ResultsFocus on radio performances • Relatively poor radio signal in NoLOS scenario • Trees do affect a lot the radio link • The higher the frequency, the higher the attenuation • Very good results in LOS situations • 19 Mb/s with a 700m radio link • Throughput degradation at each hop • Despite the use of separate dedicated radios • Degradation isn’t 50% as in a 1 radio scenario, but still around 30 to 40%

  17. ResultsWithin Eu-Mesh • Tests already done : benchmark for EU-Mesh enhancements • Many further tests can be done • Playing with frequencies allocations • Changing power settings • Whatever you want to test …and see the impact on performances…

  18. MobilityThe problem • Goal is to offer the client a seamless experience • Even if he is moving • pedestrian or « car-in-paris-traffic-jam » speed • he doesn’t care which AP he is connected to, and even less which backhaul this AP is using • Lamppost may be backhauled by different Ozone’s aggregation point • 3 in our case, with IP addressing specific to each of them • Lampposts may be backhauled by other technology • DSL, Fiber, 3G, Wimax (all of these from Neuf Cegetel / SFR) • Lampposts may be backhauled by other providers

  19. MobilityOur solution : tunneling + Transparent to the user No need to deploy third party software on clients devices + Simplify provisionning of AAA and captive portal Only need to allow each AP to connect to the network (affect IP address and gateway) : tunnels go live automaticaly - Has an impact on available throughput Overhead of tunnels : from 10% to 40% today, depending on adopted solution

  20. MobilityOur Tunnel solution : OpenVPN + Very easy to configure Available for a very large number of hardware platforms and OSs + Can handle NAT without any problem GRE can’t, IP-Sec needs Nat-traversal + Can handle No MTU Problems - ??

  21. MobilityArchitecture • All tunnels are bridged at the controller • No IP change for the client when changing association • Roaming possible between various lampposts

  22. MobilityArchitecture • Roaming also possible between lampposts and DSL « box »

  23. MobilityFirst conclusions • Roaming times depend on client’s wifi driver implementation • When they consider a signal is too weak and switch to a better one • Tunnels may deliver this feature • Efficiency depends on Wifi reassociation times • …but has a non negligeable impact on performances • 8 to 10 % in our current solution (OpenVPN on UDP, no encryption) • And is dependent on network architecture • Tunnels will be shut down if mesh architecture changes ; need to be able to go live very fast after such a change • … just a transitionary solution to « real mobility » features • To be developped within EU-Mesh (Wioptimo…)

  24. MonitoringTools and how-to exploit them • Classical monitoring tools • Cacti • Nagios • Netflow exploitation • Nfsen • Able to compare usage of « fixed-wireless » clients vs « Mobile » clients • On protocol, ports, type of application… • Might be interesting within EU-Mesh as an input on what usage is made of a wireless (mesh) network, and impact this usage has on the network

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