Wireless%20Solutions%20in%20Developing%20Countries

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Wireless Solutions in Developing Countries

• Lessons learned in Latvia and around the World

Guntis Barzdins (guntis_at_latnet.lv) Taide
Network and University of Latvia (Latnet) John
Tully (tully_at_mt.lv) MikroTikls SIA and
Latnet Arnis Riekstins (rieks_at_mt.lv)
MikroTikls SIA and Polymer Mechanics Institute
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Agenda

• Latnet and MikroTikls - who are we?
• Wireless Internet in Latvia and elsewhere
• Elements of wireless Internet access
• Wireless Components
• Software
• Issues to Consider Traditional and New solutions

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Short history of Wireless Internet in Latvia

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

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Current Activities

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

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Latnet and MikroTikls assisted Wireless
installations since 1993
S.KOREA
GHANA
PERU
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(No Transcript)
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Actual reason for Wireless

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

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Example from Latvia

• 11Mbps Wireless Internet access
• Installation
• PC router 450
• Wireless card 800
• Antennacable 250
• Monthly fee
• wireless link 0
• Internet 300

• 128Kbps Leased line Internet access
• Installation
• Leased line installation 900
• Cisco router 1400
• Monthly fee
• leased line 250
• Internet 300

Wireless isHalf-duplex Multi-point but100x
faster
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What is a Wireless Internet access?
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Equipment regular 2.4GHzLicense-fee wireless
LAN

• Central site
• omni-directional antenna
• wireless bridge or access point
• increased performance
• increased reliability

• User site
• high-gain directional antenna
• PC router with wireless card
• router separates user LAN(firewall)
• back-up routing through dial-up
• cheaper than WirelessBridge Cisco router

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How to make Wireless link cheap but reliable?

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

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Wireless LAN Card Vendors
ourpreference

• All listed devices support up to 11 Mbps, operate
  in 2.4GHz license-free ISM band, and use Spread
  Spectrum technology
• IEEE 802.11 compliance is optional - in long
  range applications top performance can be
  achieved only with same vendor equipment

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Antennas Cables Connectors

• Cables
• L-loss cable designed for 2.4GHz (1dB loss per 1
  meter is a good value)
• Use short cable! (30m max)

• Connectors
• Because of FCC regulations, cards have custom
  connectors - hard to get, expensive
• Water in connector is the most frequent problem.
  Apply HERMETIC isolation to connectors ALWAYS!

• Antennas
• User site24dBi directional grid antenna
• Central site5.5-8dBi or more Omni-directional
  antenna
• Lightning protection!
• Snow cover in arctic regions

oursuggestion
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Environmental Aspects

• Direct line of sight required
• Rain and snow has no influence on the link
• Distances
• 12km radius around the Access Point for
  point-to-multipoint connections (4km with ETSI
  compliant antennas)
• 40km between two nodes with directional antennas
  for point-to-point links (10km with ETSI
  compliant antennas)
• Amplifiers amplify also noise - avoid them!

• Distance calculator
• cable length
• antenna gain
• speed
• power
• http//www.ltn.lv/guntis/smarp/

oursuggestion
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PC routing software - DOS and Windows

• Windows NT (too bulky)
• Windows 95/98 cannot route!
• DOS based IP routers (up to 2Mbps only!)
• PCroute has no remote, VLSM (free)
• IProute by Dave Mischler (license 50)
• KA9Q, JNOS, TNOS,... (free, but slow and
  unreliable)

ourpreference
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PC Routing Software - UNIX

• Linux Router Project
• good, but few wireless cards have working Linux
  drivers
• FreeBSD based router - same problem
• MicroTik wireless router software(Linux based)
• supports most Wireless and ordinary NICs
• remote management via telnet and http
• wireless network diagnostics testing options
• commercial version 300

ourpreference
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Use Aironet Bridge as a Router
New!

• Price PCWirelessCardWirelessBridge
• Bridge works at -20C can be mounted at antenna
  outdoors (increased range)
• Bridge acts as a repeater micro-cells
• Bridge can be configured to
• Forward all unicast frames
• Discard all multicast/broadcast frames
• Filter frames on additional header fields
• Server-based ARP needed SmartARP

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SmartARP configuration
New!
Free SmartARP for Win95 and LINUX
at http//www.ltn.lv/guntis/smarp/
MAC addressof smartARP server B
Configuration file of SmartARP server A
10.1.1.0 255.255.255.0 local 10.1.2.0
255.255.255.0 forward 00013a4c12 10.1.3.0
255.255.255.0 forward 007318a562 10.1.4.0
255.255.255.0 forward 000c63527a
MAC addressof smartARP server C
MAC addressof smartARP server D
Ranges of IP addressesassigned client networks
What to do with ARP requests
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Future

• Routing and VLANs complex to manage with 100s of
  permanently connected customers (with backup
  links)
• Max auto-configuration is needed Bridging with
  IP prefix filter vs. Routing
• Substitute for inefficient Spanning Tree Protocol
  (STP) used by Bridges

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Conclusion Preferred Solution

• Aironet 11Mbps Turbo DS
• Bridge BR500-E or AP4800 (central site)
• PCrouter with ISA or PCI4800 (client)
• Routing software
• IPRoute (50)
• MikroTik router software (300)
• SmartARP software (free)
• Quality Cables, Antennas, Connectors
• Up to 20 clients per cell of 7-12km radius(in
  city environment use 1-2km micro-cells
  microwave or fiber backbone)

TREND
Use wires and same software to share Internet
connection with neighbors
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References

• Slides available athttp//www.ltn.lv/guntis/sma
  rp/
• Latnet (operates wireless network in
  Latvia)http//www.latnet.lv
• MikroTikls (wireless hardware
  software)http//www.mt.lv
• Taide Network (satellite communications)http//ww
  w.taide.net