PDA Based Kiosk System

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PIKS OVER BLUETOOTH
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Part 1 Overview

• We learned Bluetooth and PIKS theory
• Experiments with the iPaq 3870
• COM port emulation over RFCOMM
• We came to a crossroad Find the best way to
  connect the clients to the Access Point
• WLAN or Bluetooth ?

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PIKS in short

• Personal Information Kiosk System
• Designed to give a fast, cheap and simple way to
  get location specific information
• Our goal design and implement a PIKS over
  Bluetooth, thus exploiting its characteristics
• Low power consumption
• Cheap
• Simple to operate
• Supports the client server principle (piconet)

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The model
Server
AP
AP
AP
Bluetooth
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The decision

• Bluetooth was chosen due to the following
  parameters
• More Innovative
• WLAN is already well implemented (no real
  challenge)
• Exploit the existing Bluetooth capability of the
  iPaq more intuitive, saves power and money (as
  is)
• Open the way for future works on IP over
  Bluetooth Stack

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• BlueZ is the official Linux Bluetooth stack. It
  provides support for core Bluetooth layers and
  protocols.
• Support for multiple Bluetooth devices
• Multithreaded data processing Flexible, efficient
  and modular architecture
• Hardware abstraction
• Standard socket interface to all layers

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The Bluetooth Hardware

• Bluetooth chip by Ericsson specification

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iPaq Bluetooth capabilities

• The BlueCore-PDA core stack consists of the
  following
• Bluetooth protocol upper layers
• GAP (Generic Access Profile)
• SPP (Serial Port Profile)
• SDAP (Service Discovery Application Profile)
• FTP (File transfer Profile) Client and Server
• OPP (Object Push Profile) Client and Server
• DUN (Dial up Networking) Client
• LAN (LAN Access Networking) Client
• Active SYNC
• GOEP (Generic Object Exchange Profile)

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BlueZ fundamentals

• Bluez stack implemented via Bluez kernel and
  Bluez packages
• The stack is operated using daemons
• What is a daemon ? A synonym for server,
  particular to software designed for UNIX systems.
  Not to be confused with demon, which is an evil
  spirit
• Give access to the stack elements properties
• Daemons we used hcid, sdpd, rfcommd, pppd.

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Bluez kernel

• Bluez has a core package called bluez-kernel that
  includes all needed in order to set up the core
  of bluetooth.
• Also Included in the bluez-kernel code is HCI USB
  driver, RFCOMM protocol and more.

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HCID

• Host Controller Interface (HCI)
• The HCI provides an abstraction standard for
  interface to Bluetooth hardware, dictating the
  operations which the core Bluetooth stack should
  carry out at the interface to the hardware
  specific driver.
• Essentially this interface provides a uniform
  method of accessing the Bluetooth baseband
  capabilities.

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SDPD

• Service Discovery Protocol (SDP) The service
  discovery protocol (SDP) provides a means for
  applications to discover which services are
  available and to determine the characteristics of
  those available services.
• SDPd - server Daemon that listens on L2CAP and
  Unix sockets. it should respond on incoming SDP
  queries, maintain SDP database, allow record
  registration via unix socket, etc.

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RFCOMMD

• RFCOMM Protocol- provides emulation of serial
  ports over the L2CAP protocol. The rfcommd,
  provides the RFCOMM service. It listens for
  RFCOMM requests and then establishes the serial
  connection and hands it to a program such as
  pppd.

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pppd

• The PPP daemon - pppd - is the program that makes
  the PPP connection.
• pppd manages the dialing process (often using a
  separate program) and then negotiates the
  connection with your ISP.
• The negotiation process includes a set of steps,
  using a set of protocols such as LCP (Link
  Control Protocol), authentication protocols, NCP
  (Network Control Protocol) and IPCP (Internet
  Protocol Control Protocol).
• Each of these "curses" denotes a step in the PPP
  connection setup. If the connection fails,
  determining which sub-protocol caused the failure
  is half the way to locating the configuration
  problem.

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Bluez packages

• Bluez-libs
• Bluez-utils
• Bluez-SDP
• Bluez-PAN - Personale Area Networking
• DUN - Dial Up Networking
• Bluez-Hci_emu Device Emulator
• Bluez-fw Firm Ware
• Bluez-Hci_dump HCI level event monitor

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How do we fit in??

• Learning the entire structure and hierarchy of
  the Bluez stack modules and installing them
• Creating new nodes in the file system to be used
  as rfcomm connection endpoints
• Editing and adapting each communication level of
  the stack used to create the connection to the
  Ipaq
• daemons conf. files
• Creating an rfcomm device
• BT configuration
• Building a super script
• Running each daemon with its configuration and at
  the right time
• Presenting the system events log
• Implementing the communication layers up to IP
• Creating a server that establishes connections on
  demand with a bank of IPs
• Running ProxyArp server

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Configuring IP over Bluetooth

• PC (server) side
• Connect the Hardware to the PC via USB
• Run the hcid with appropriate conf file
• Run sdpd with appropriate conf file
• Run rfcommd with appropriate conf file
• PDA (client) side
• Search for devices and discover the server (sdp)
• Choose the connect to LAN access point option
• In this stage, pppd starts on the PC (invoked by
  the rfcommd) and starts the ppp connection.

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Server side
Client side
gtHCID gtSDPD gtRFCOMMD
gtSDP gtconnect to LAN AP
Listens for connections
PPPD starts
ip/ppp established
time
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Proxyarp

• Proxy ARP (Address Resolution Protocol) -
  basically means that a particular machine will
  respond to ARP requests for hosts other than
  itself.
• Using Proxy ARP with subnetting in order to make
  a small network of machines visible on another
  Internet Protocol (IP) subnet. This makes all the
  machines on the local network appear as if they
  are connected to the main network.
• Thus, saving some valuable IP addresses to
  the organization.

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Proxyarp cont.

• Motivation The entire throughput of the
  established piconet already goes through the
  Master unit (our Access Point), meaning a PDA can
  not access the network by it self due to the
  nature of BT, so making the master unit PC a
  proxyarp is both intuitive and it saves the use
  of real IP addresses

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Proxyarp diagram
A
B
LAN
A responds to ARP requests for the BT dongle with
its MAC
Bluetooth dongle
Wireless
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Building a web based PIKS

• An adaptation to the original design
• We have TCP/IP can use web based applications
• Building a simple text based screens
• Advantages quick, easy to program, maintain and
  easy to upgrade to a more graphical screens

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PIKS demo

• http//comnet.technion.ac.il/cn16s02/piks-demo.ht
  ml
• Uses text screens similar to the original IBM
  PIKS application
• Shows an example for an entire PIK System
• THE GOAL WAS ACHIEVED !!!

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Summary

• BT was proved to be a good solution
• The good thing Ipaq remains as is
• Performance
• Fast with text screens
• Several clients concurrent
• Reliable connectivity
• Providing a base for future development of
  network apps over IP over BT