1. Mesh networksusing commodity WiFi routers and OpenWRT Alexander List Open Source Workshop #5 (7 Apr 2012)City University of Hong Kong

2. Network topologies http://en.wikipedia.org/wiki/Network_topology 3. Mesh networkhttp://en.wikipedia.org/wiki/Wireless_mesh_network 4. WiFiIEEE 802.112.4 GHz ISM band (100 mW EIRP), ch. 1-1460 MHz 3 non-overlapping channels (1/6/11)5 GHz ISM band (up to 1W EIRP)Indoor channels (5.15 5.25 GHz, ch. 36-48)Outdoor channels (5.25 5.6 GHz, ch. 52-140)Always check national regulation (HK: OFCA) 5. Typical WiFi deployment(c) eTutorials.org 6. 802.11 modesInfrastructure mode (STA AP)Home networkOfficeCafAd-hoc mode (STA-STA)Mac OS create network (AirPort menu)Linux: iwconfig wlan0 mode Ad-HocUbuntu: using Network Manager 7. Commodity hardwareLinksys WRT54G seriesGL runs Linux 8. WiFi chipsets 9. China: TP-LinkTL-WR703N: 57x57x18mm, ~RMB 95 57x57x18mm Atheros AR7420, 4MB flash, 32MB RAM 1x 10/100 Mbit/s Ethernet, USB 2.0, 802.11nTL-WR743ND: ~200 HKD Atheros AR7420, 4MB flash, 32MB RAM 5x 10/100 Mbit/s Ethernet, 802.11nTL-WR1043ND: ~390 HKD Atheros AR9132, 8MB flash, 5x GigE, 3xMIMO 10. Buying hardwareCheck http://wiki.openwrt.org/toh for supportGo for more flash ( 8 MB)Detachable antennas12V DC power supplySeveral LAN ports 11. OpenWRT 12. OpenWRTLinux kernelOwn build/packaging systemOriginally derived from Linksys WRT54G GPL sourcesActive community, supports 100s of devicesMesh network protocols availableAsterisk, MySQL, ... 13. Wireless mesh protocolshttp://battlemesh.org/OLSR, B.A.T.M.A.N., Babel, BMX, 802.11s, ... 14. Wireless community networksGermany: Freifunk in several citiesAustria: FunkFeuer (120/200 nodes)Athens: AWMN (2433 nodes)Barcelona: guifi.netOverview: http://en.wikipedia.org/wiki/List_of_wireless_community_networks_by_region 15. FunkFeuer Graz 16. AWMN 17. Spain: guifi.net 18. Asia?!India: AirJaldiIndonesia: BWICNepal: nepalwireless.net 19. What do we need? 20. Lets get this party started...When:Saturday, May 12, 2012, 14:00-17:00Where:DimSumLabs, 14/F, 100-102 Jervois Street, Sheung WanBring:Laptop, WiFi router supporting OpenWRT 21. Thank you!