7DS Seven Degrees of Separation

1
7DSSeven Degrees of Separation

• Suman Srinivasan
• IRT Lab
• Columbia University

2
Problems with Wide Area Wireless

• 802.11 currently hard to deploy across city or
  large area
• Problem How can mobile devices / gadgets get
  information?
• Solution 7DS!

3
Concept

• Use local peer-to-peer wireless networks to
  exchange information
• Peers can get information they do not have from
  another peer
• Once wireless 7DS network set up, it could be
  used for any purpose
• Getting web pages from peers
• Sending e-mails
• File transfer to selected client

4
Illustration
In the absence of the Internet, nodes can
exchange information amongst themselves
Internet
5
Design

• Peer-to-peer network set up using zeroconf
• Protocol enables devices to get IP address and
  communicate without a DHCP / other server
• Proxy server serves content
• If connected to Internet, functions normally
• If not connected, connects to peers to get
  information

6
Design

• Search engine
• Allows self / peers to search within the devices
  database for necessary information
• Multicast querying system
• Allows peers to query systems in peer-to-peer
  network
• Searches can be for files or keywords
• Transport System
• To forward e-mail

7
Design
8
Connection Proxy Server

• Connection set up using zeroconf protocol
• Similar to AppleTalk, Microsoft NETBIOS, Novell
  IPX
• Uses link-local addressing, multicast DNS, DNS
  service discovery
• Proxy server
• Peers user client uses localhost proxy server by
  default
• Detects Internet connection availability
• If Internet, normal network operation
• No Internet, peer-to-peer data exchange

9
Search Engine

• Provides ability to query self for results
• Searches the cache index using Swish-e library
• Presents results in any of three formats HTML,
  XML and plain text
• Similar in concept to Google Desktop

10
Query Multicast Engine

• Used to actually exchange information among peers
• Requesting peer broadcasts a query to the network
• Responding peers reply if they have information
• Send encoded string with list of matching items
• Requesting peer retrieves suitable information

11
Conclusion

• 7DS allows data retrieval and transmission, even
  in absence of Internet
• Exchange of information within local network
• Nodes that eventually connect to larger network
  facilitate new information exchange
• No user intervention unless absolutely necessary
• New step in practical, large-scale wireless
  networking with gadgets?
• Remains to be seen