WAWC

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WAWC05

• Enhancing Mobile Peer-To-Peer Environment with
  Neighborhood Information
• Arto Hämäläinen - arto.hamalainen_at_lut.fi

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Outline

• Introduction to PeerHood - a Peer-to-Peer
  neighborhood
• overall structure and detailed technical
  architecture
• Neighborhood Information exchange
• Usage Scenarios
• Evaluation

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PeerHood - Peer-to-peer neighborhood

• PeerHood is an environment consisting a number
  of personal trusted devices (PTDs), e.g. mobile
  phone, PDA, laptops
• PTDs sense their neighbors in the changing
  mobile environment using different network
  technologies

PeerHood layer in PTD
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PTDs and their neighborhoods
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PeerHood - Peer-to-peer neighborhood

• Methods for searching depend on used network
  plug-in
• In Bluetooth, its device and service discovery
  mechanisms are used, own methods in Wi-Fi and
  GPRS
• Devices found are then stored in the local device
  database
• PeerHood provides a common network interface to
  connect to other PeerHood devices - independent
  from the underlying communications technology

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PeerHood components
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PeerHood class diagram
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PeerHood library interface

• Applications in PTD can send requests for the
  PeerHood daemon through the PeerHood library
• Available functions include methods to list
  available devices and services, register and
  unregister local services offered by the
  application and to connect remote devices and
  services
• Library interface also includes common read and
  write methods
• Same read and write methods for every network
  plugin

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Neighborhood information exchange

• Neighborhood information exchange is used to
  gather information about the neighboring devices
  from already discovered devices
• Possibly revealing undiscovered devices and
  services
• It can be used to speed up the device and service
  discovery and locate services not reachable with
  network technology currently in use
• The neighborhood information exchange can either
  be enabled or disabled in devices, more detailed
  configuration is planned

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Neighborhood information exchange

• Neighborhood information exchange is carried out
  by the PeerHood daemon
• Its enabled or disabled using the configuration
  file or manually registering local neighborhood
  info service through the PeerHood library
  interface
• If a remote device offers neighborhood
  information service, request is sent to the
  device and response is stored in local device
  database with the information about the offering
  device

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Neighborhood information exchange, usage
scenarios

• Personal networking outside the immediate
  vicinity
• interesting services found through neighborhood
  information exchange could be reached using
  longer range technology or via gateway device
• Exchange of detailed device information
• Service-specific information offered
• Dedicated service discovery
• Mobile device could use a dedicated device to
  carry out their device discovery (e.g.
  office/home PC) to save own batteries

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Neighborhood information exchange

• Device discoveries may fail, and neighborhood
  info can be used to get information about
  undiscovered devices

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Evaluation

• To evaluate the neighborhood information
  exchange, ten tests were carried out with and
  without it - in a situation corresponding to MSC
  in previous slide

• Fixed and mobile devices had different intervals
  in device discovery
• Time taken to find two other PeerHood devices was
  measured

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Conclusions and future work

• Neighborhood information exchange can be used to
  speed up device discovery in peer-to-peer
  environment and to find out devices outside the
  immediate vicinity or use alternative device
  discovery solutions
• Further work is still needed
• the roles and nature of different devices needs
  to be defined and implemented
• security and trust issues to be addressed as
  well as more detailed configuration of operation