Transcript Low-Cost Internet Access Using KioskNet

Low-Cost Internet
Access Using KioskNet
Earl Oliver
PhD Student
Tetherless Computing Research Group
University of Waterloo (Canada)
With: S. Guo, H. Falaki, S. Ur Rahman, A. Seth,
M. Zaharia, U. Ismail, and Prof. S. Keshav
Key points
• Robust, reliable, and low-cost network
connectivity for rural regions
• Supports incremental deployment by
franchisees (secure)
• Secure communication between users and
the Internet
• Supports future network availability (ex.
WiMAX, cellular, etc.)
• Available today, free for download
Why low cost networking?
• Access to timely, context-specific information can greatly
benefit citizens of developing countries
• Farmers
– Best agricultural practices
– Crop inputs and treatments
– Market prices
• Health workers
– Diagnosis
– Treatment
• Citizens
– Government services
– Communication (email)
Example
• aAqua project (IIT Bombay, Maharastra, India)
– Bulletin board system allows farmers to consult with agricultural
experts
• market opportunities
• fertilizers
• pricing
• Sample questions:
– How much money can you make from a Jersey cow worth Rs.
20,000 in a year?
– I want information of producing and implementation of Jatropha
plant for Bio-Diesel.
– We have at our disposal 10-12tonnes of aloe vera plants/leaves
for sale. Parties interested in purchasing please catch us at 09864031770
Low cost communication and
access to information…
• Allows better decision making
• Improves worker productivity
• Integrates economies into the world
market
• Prevents `leakage’ of development funds
• Promotes an informed citizenry and a
participatory democracy
How to provide low-cost access to
information?
Information access today
• Mostly one-way
– Radio
– TV
– Newpapers
– Magazines
• These solutions are inadequate
Two way information flow
• Possible using newer technologies
– Cell phones
– Internet
• But can be expensive
– Rural poor are unlikely to get good
connectivity any time soon
– Revenue per sq. km << cost per sq. km
• Can we provide reliable connectivity for
only a few dollars / person / year?
How to reduce costs?
• Sharing the cost of the technology
• Sharing the cost of knowing how to use
the technology
• Information kiosk
Kiosk connectivity
• Dial-up
– Slow (28 kbps) and flaky
• Satellite (Very Small Aperture Terminals)
– Expensive and slow
– Spare parts are hard to get
• Long range WiFi / WiMax
– Experimental
– Expensive up-front cost (for 18m tower)
• Cellular broadband (3G)
– Low penetration because of high upfront costs
Mechanical backhaul
Kiosk
The Kiosk controller
• Headless, keyboardless, low-cost, lowpower single board computer.
• Powered by solar power + battery
– (near full uptime)
• Supports wide range of network interfaces
– Choice of interface is policy driven at the
session layer
Kiosk controller cont’d
• Two access modes:
– Terminal: recycled
PCs netboot from a
read-only image
stored on the kiosk
controller.
– Direct: access the
controller (or bus or
gateway) like a WiFi
hotspot.
Ferry
Gateway
Ferries and gateways
• No processing of data – only store and
forward
– Without power restrictions
– Recommended to have faster CPU, higher
memory than kiosk controller
• Gateway has an always-on connection to
the Internet (proxy)
Proxy
• Centralized server on the Internet
• Disconnection-aware
• Hides disconnected users from legacy
servers
• Plug-in applications
– Ex. SMPT plug-in to handle email service
• DNS location register
• Public key database (whitepages
directory)
Advantages of mechanical
backhaul
• Low cost of connectivity per kiosk (< $250
capital expenditure)
– Cost of the ferry and gateway single board computer
gets shared across kiosks
– $3/person/year to break even at 10% penetration
• no trench, no tower !
• See paper for calculations and cost breakdown.
• Increased penetration
– Even in interior areas where there are no telephone
lines
• High bandwidth data transfer in both directions
• Rapidly and incrementally deployable
Disadvantages
• Data transfer is delayed
– Depends on frequency of visits of vehicles
– Can be several days
• But many useful applications are delay
tolerant
– Trade delay for cost
• Suitable for smaller non-governmental
organizations to set up kiosks
Low cost connectivity 
• What are the challenges?
–
–
–
–
–
Supporting multiple network interfaces
Security
Routing
User management
Maintenance and redundancy (debugging system
failure)
Supporting multiple NICs
• Need to support new networks
• Mechanical backhaul not ideal for all
applications
– Ex. High priority data
• Opportunistic Connection Management
Protocol (OCMP)
– Applies application specific policies to
schedule data across multiple NICs
– Currently mechanical backhaul, SMS, and
TCP/IP supported.
Security
• Resilient to a diverse set of internal and external
attacks
• PKI rooted at University of Waterloo
– sub-CAs operated by KioskNet franchisers and
franchisees
– X.509 public keys flooded to kiosks to provide secure
communication between users
• Encrypted user file system
– Keyed by user password, NFS mounted at logon
• Kiosk netboots from read-only image stored on
the kiosk controller
Routing
• Many DTN routing options
– Robustness vs. efficiency
– Guaranteeing reliability is hard
• Flood within a ‘region’
– Hierarchical namespace:
<kiosk>.<region>.<provider>.kiosknet.org
• Upstream: gateways coordinate to send one
copy of data to proxy
• Downstream: data sent to one region’s gateway
– DNS query based on user EID to determine gateway
User management
• Distribute user creation to kiosks
– Walk in, get an account
• Extended system admin application:
webmin to create/delete users and public
keys
• Keys are signed by the local franchisee
and sent to the proxy with the user’s EID
– <user>.<kiosk>.<region><org>.kiosknet.org
• EIDs and certificates flooded back to all
kiosks
Maintenance and redundancy
• Applying software updates/bug fixes can be
expensive
• Robust mechanism for pushing updates (debian
packages)
• Remote shell for remotely executing bash scripts
• Software failures can occur in the field
– Need a mechanism to collect debugging information
• rsync/ssh flooding of logs
– Activated by inserting a special USB key or via
remote shell
Sample applications
• Email
– Classic application for delay tolerant networks
– user@<kiosk>.<region>.<org>.kiosknet.org
• Database synchronization
– Replicate a centralized database to kiosks
– Ex. aAqua (IIT Bombay)
• YouTube
– Download videos to kiosk based on a search query
• Flickr
– Take a picture, upload it to Flickr
Current status
• Live deployment in Anandpuram, India
• Second deployment mid December (IIT
Delhi)
• Preparing second major release for early
2008 that includes security, SMS, and
DNS user lookups
Future work
• Support for mobile users
– Routing, security, user management
– Recycled cell/smart phones
• Robustness
– Exploit the cellular network as a control
channel
• Applications, applications, applications
– “if you build it they will come” might not apply
Conclusions
• Developed a secure, robust system to
provide low-cost Internet to rural regions
• KioskNet can adapt to the availability to
new networks
• KioskNet is free and rapidly deployable
For more information
• Earl Oliver, [email protected]
• Prof. Keshav, [email protected]
• Web:
http://blizzard.cs.uwaterloo.ca/tetherless/
• Join our mailing list