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

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

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

5 Hardware  Mikrotik RB532  MIPS architecture  3 Mini-PCI slots  3 * CM9 wifi cards  Atheros chipset  Dual-band antennas  4,5 2.4GHz  7 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 730 m 500 m

9 Coverage achieved  Over m² covered

10 Coverage achieved

11 Coverage achieved  Focus on the « Hotel de Ville » area  « seamless » wifi mobility within this area  m²

12 First impressions cf. 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 impressions cf. 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 Results Focus on radio performances

16 Results Focus 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 Results Within 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 Mobility The 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 Mobility Our 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 Mobility Our 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 Mobility Architecture  All tunnels are bridged at the controller  No IP change for the client when changing association  Roaming possible between various lampposts

22 Mobility Architecture  Roaming also possible between lampposts and DSL « box »

23 Mobility First 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 Monitoring Tools 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