Wireless Solutions in Developing Countries Lessons learned in Latvia and around the World Guntis Barzdins Taide Network and University of Latvia (Latnet) John Tully MikroTikls SIA and Latnet Arnis Riekstins MikroTikls SIA and Polymer Mechanics Institute

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

Short history of Wireless Internet in Latvia n 1993: first 915MHz WaveLan link in Riga n : 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

Current Activities n Buildings connected to the Internet by 2.4GHz wireless links in Riga : u More than 100 u 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

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

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)

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 $ Kbps 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

What is a Wireless Internet access?

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

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?

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 compliance is optional - in “long range” applications top performance can be achieved only with same vendor equipment our preference

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

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 ~guntis/smarp/

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

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

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

SmartARP configuration local forward 00:01:3a:4c: forward 00:73:18:a5: 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: New! What to do with ARP requests MAC address of smartARP server C MAC address of smartARP server D

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 / / / Routing tableARP table IP addr MAC addr :14:0c:76: :0c:21:44:15 Bridge with IP filter, no STP IP forwarding table IP range Next Hop MAC /24 00:14:0c:76: /28 00:0c:21:44: /24 00:14:0c:76:82

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:

References n Slides available at: n Latnet (operates wireless network in Latvia) n MikroTikls (wireless hardware & software) n Taide Network (satellite communications)