Presence and IntComm WG

[Candace Holman <>]

Here's a preliminary draft of the Skiff Primer.  Jamey - I have a few 
questions in the text, and also wonder how people are going to access the 
itarget3 application or if I need to talk more about setup.  I will add 
diagrams later.  Is this the kind of document that people will find useful?

Skiff Primer
April 2004


Overview
=======================================================================

The Internet2 PIC-WG PALS demonstrations are built on an interconnected
system of server processes and wireless devices working together to
provide device tracking via a grid of calibrated reference points.

[Paste a diagram of iDaddy - iTargets - skiffs working together]

There are three principle devices that form the basis of the system - a
server that collects and organizes location information, the skiffs
that generate mapped location information, and the clients that
generate dynamic location information.

Skiffs are 802.11 wireless devices that monitor traffic from other
wireless devices for the express purpose of reporting signal strength
to servers configured to collate various source of location
information.  This document explains how to calibrate the skiffs in a
new location to produce a grid of reference points that can be used to
locate mobile devices.

Getting Started
=======================================================================

You must be running Linux on your device of choice - laptop or iPaq.
If not being run as root, make sure you designate the port to be port
22.

In order to calibrate skiffs the environment must be set up.  Do not
attempt to calibrate skiffs prior to all skiffs being placed and
running.  Itarget, the client program, runs off a preconfigured map of
the geographic location to be calibrated as shown below.

[diagram of blank map, itarget not running]

Expect to walk from skiff to skiff and wait while approximately 10,000
packets are received by the skiff.  This usually takes about 5 (?)
minutes per skiff.

The calibration program requires isolated use of your wireless card, so
do not try to run other wireless applications at the same time over the
same port. (or else?)

Checklist
=======================================================================
1. type in the command:  itarget3 -s servername [-p port]
2. choose the floor/session that you are working with

[diagram of itarget site/floor/session dialog]

3. select the room and press the start button - you will see the number
of received packets increasing
4. after receiving 10,000+ packets, and when you see the green mouse
icon as shown in the itarget Icons list below, press save

[diagram of itarget running]

5. it will ask you to confirm the new location data or to cancel
6. repeat steps 3-5 for each new room until done

itarget Icons
=======================================================================

[grey x] - location of a recorded, stable calibration point
[red x] - selected location
[green diamond] - visited location
[black rabbit ear] - skiff location
[green mouse] - data from this itarget is being actively collected

Glossary:
=======================================================================

idaddy - server that collates the information provided by the

sniffmaster process

ireflector - proxy to span firewalls in a secure PALS environment

itarget - client process that generates location data for skiffs

session - a set of calibration data provided by a skiff

signature - collection of signal strengths registered on several skiffs
from a single client in a single location

skiffs - the stationary reference points that are used to trace
wireless devices in motion

sniffmaster - process that aggregates packets from the scanner
processes running on skiffs





=====================================================================
Candace Holman
Convergence Engineer
University Information Systems
60 Oxford Street
Cambridge, MA 02138

The best things in life aren't things.