1. Wireless Solutions in Developing Countries Lessons learned in Latvia and around the World Guntis Barzdins (guntis@latnet.lv) Taide Network and University of Latvia (Latnet) John Tully (tully@mt.lv) MikroTikls SIA and Latnet Arnis Riekstins (rieks@mt.lv) MikroTikls SIA and Polymer Mechanics Institute

2. Agenda n Latnet and MikroTikls - who are we? n Wireless Internet in Latvia and elsewhere n Elements of wireless Internet access u Wireless Components u Software n Issues to Consider: Traditional and New solutions

3. Short history of Wireless Internet in Latvia n 1993: first 915MHz WaveLan link in Riga n 1994-1996: Latnet wireless network extended n 1996: paper “Wireless Internet Access in Latvia” published on the Internet n 1996: MikroTikls company founded n 1996: By contract with Taide Satellite, MikroTikls installs first 2.4GHz wireless network in Moldova n 1996-present: queries from around the World

4. Current Activities n Buildings connected to the Internet by 2.4GHz wireless links in Riga : u 1997 - More than 100 u 1998 - More than 200 u 1999 (May) - More than 300 n Also 15 regional cities in Latvia have wireless Internet access n Wireless installations & consulting worldwide n Development of new wireless solutions

5. Latnet and MikroTikls assisted Wireless installations since 1993 On-site installation by our staff Equipment supplied or Installation consulted GHANA S.KOREA PERU

7. Actual reason for Wireless Wireless Internet is cheaper than Leased line Internet access Other reasons u leased lines not available u low quality dial-up lines u national telecom monopoly u quick installation u better throughput (up to 11Mb/s)

8. Example from Latvia 11Mbps Wireless Internet access n Installation u PC router $450 u Wireless card $800 u Antenna&cable $250 n Monthly fee u wireless link $0 u Internet $300 128Kbps Leased line Internet access n Installation u Leased line installation $900 u Cisco router $1400 n Monthly fee u leased line $250 u Internet $300 Wireless is Half-duplex & Multi-point but 100x faster

9. What is a Wireless Internet access?

10. Equipment: regular 2.4GHz License-fee wireless LAN Central site u omni-directional antenna u wireless bridge or access point F increased performance F increased reliability User site u high-gain directional antenna u PC router with wireless card F router separates user LAN(firewall) F back-up routing through dial-up F cheaper than WirelessBridge + Cisco router

11. How to make Wireless link cheap but reliable? n Components are cheap, integrated solutions are expensive and inflexible. Do it yourself: u Which wireless LAN vendor and product to choose? Which parameters matter? u What antennas and cables will work the best? u Which PC routing software to use? What are known problems with each of them? u What communication distances are realistic and what influences that? Will power amplifier extend the range?

12. Wireless LAN Card Vendors n All listed devices support up to 11 Mbps, operate in 2.4GHz license- free ISM band, and use Spread Spectrum technology n IEEE 802.11 compliance is optional - in “long range” applications top performance can be achieved only with same vendor equipment our preference

13. Antennas & Cables & Connectors n Cables u L-loss cable designed for 2.4GHz (1dB loss per 1 meter is a ‘good value’) u Use short cable! (30m max) n Connectors u Because of FCC regulations, cards have custom connectors - hard to get, expensive u Water in connector is the most frequent problem. Apply HERMETIC isolation to connectors ALWAYS! n Antennas u User site:24dBi directional grid antenna u Central site:5.5- 8dBi or more Omni-directional antenna n Lightning protection! n Snow cover in arctic regions our suggestion

14. Environmental Aspects n Direct line of sight required n Rain and snow has no influence on the link n Distances: u 12km radius around the Access Point for point-to-multipoint connections (4km with ETSI compliant antennas) u 40km between two nodes with directional antennas for point-to-point links (10km with ETSI compliant antennas) n Amplifiers amplify also noise - avoid them! our suggestion Distance calculator: cable length antenna gain speed power http://www.ltn.lv/ ~guntis/smarp/

15. PC routing software - DOS and Windows n Windows NT (too bulky) n Windows 95/98 cannot route! n DOS based IP routers (up to 2Mbps only!) u PCroute has no remote, VLSM (free) u IProute by Dave Mischler (license $50) u KA9Q, JNOS, TNOS,... (free, but slow and unreliable) our preference

16. PC Routing Software - UNIX n Linux Router Project u good, but few wireless cards have working Linux drivers n FreeBSD based router - same problem n MicroTik wireless router software(Linux based) u supports most Wireless and ordinary NICs u remote management via telnet and http u wireless network diagnostics & testing options u commercial version $300

17. New! Use Aironet Bridge as a Router n Price: PC+WirelessCard=WirelessBridge n Bridge works at -20C: can be mounted at antenna outdoors (increased range) n Bridge acts as a repeater: micro-cells n Bridge can be configured to: u Forward all unicast frames u Discard all multicast/broadcast frames u Filter frames on additional header fields n Server-based ARP needed: SmartARP

18. SmartARP configuration 10.1.1.0 255.255.255.0 local 10.1.2.0 255.255.255.0 forward 00:01:3a:4c:12 10.1.3.0 255.255.255.0 forward 00:73:18:a5:62 10.1.4.0 255.255.255.0 forward 00:0c:63:52:7a Configuration file of SmartARP server A: MAC address of smartARP server B Ranges of IP addresses assigned client networks Free SmartARP for Win95 and LINUX at: http://www.ltn.lv/~guntis/smarp/ New! What to do with ARP requests MAC address of smartARP server C MAC address of smartARP server D

19. Future n Routing and VLANs complex to manage with 100s of permanently connected customers (with backup links) n Max auto-configuration is needed: Bridging with IP prefix filter vs. Routing n Substitute for inefficient Spanning Tree Protocol (STP) used by Bridges Traditional IP router IP range Next Hop IP 192.12.76.0/24 199.1.2.13 194.42.32./28 193.5.77.1 198.4.15.0/24 199.1.2.13 Routing tableARP table IP addr MAC addr 199.1.2.13 00:14:0c:76:82 193.5.77.1 00:0c:21:44:15 Bridge with IP filter, no STP IP forwarding table IP range Next Hop MAC 192.12.76.0/24 00:14:0c:76:82 194.42.32./28 00:0c:21:44:15 198.4.15.0/24 00:14:0c:76:82

20. Conclusion: Preferred Solution n Aironet 11Mbps Turbo DS u Bridge BR500-E or AP4800 (central site) u PCrouter with ISA or PCI4800 (client) n Routing software u IPRoute ($50) u MikroTik router software ($300) u SmartARP software (free) n Quality Cables, Antennas, Connectors n Up to 20 clients per cell of 7-12km radius (in city environment use 1-2km micro-cells + microwave or fiber backbone) Use wires and same software to share Internet connection with neighbors TREND:

21. References n Slides available at: http://www.ltn.lv/~guntis/smarp/ n Latnet (operates wireless network in Latvia) http://www.latnet.lv n MikroTikls (wireless hardware & software) http://www.mt.lv n Taide Network (satellite communications) http://www.taide.net