TeleWeb: Loosely Connected Access to the World Wide Web

Bill Schilit, FX Palo Alto Laboratory, Inc.
Fred Douglis, AT&T Research
David Kristol, Lucent Technologies, Bell Laboratories
Paul Krzyanowski, Lucent Technologies, Bell Laboratories
James Sienicki, Lucent Technologies, Bell Laboratories
John Trotter, Lucent Technologies, Bell Laboratories

Ubiquitous information access

Wouldn't it be great if I could find any information I wanted anytime, anywhere?

Wouldn't it be great if I could browse the Web anytime, anywhere, whether I'm connected to a continuous, high-speed, low-cost network or not?

(on my laptop machine over Ethernet, CDPD, WaveLan, Metricom, modem, ..., or disconnected!)

Why is this hard?

• Browsers expect fully-connected, high-speed networks
  
• Mobile systems are "surprising" and not "seamless"
  
• People can't control costs
  

See the paper for a list of specific challenges of mobile web browsing

TeleWeb

What would the "look and feel" of such a system be? How would the system adapt to the characteristics of different networks? How would the system operate when not connected to a network? What would the system architecture be?

Scenerio: Meet Jack Webb

Meet Jack Webb and his TeleWeb enhanced laptop computer.

Jack needs documents from his company's intranet web for a presentation in Atlanta. He'll put it together on route!

Note, Jack experiences changing connectivity and communication costs:

• In the Office laptop is docked to a fast ethernet
• At Home laptop is connected over a slow dial-in modem
• On the Airplane laptop is disconnected (or very expensively connected)

How can Jack work in this dynamically changing world?

Scenerio: In the office...

• Jack's timer-style downloads have kept the laptop's cache "interesting":
URL:
When:

ThisNextEvery

MondayTuesdayWednesdayThursdayFridaySaturdaySundayM-F
Time:

123456789101112

000510152025303540455055

AMPM
Jack pins and purges cache documents before leaving
He has set his proxy to automatically change when switching from docked to dialed-in

Scenerio: At Home Packing...

Scenerio: On the airplane...

Key Ideas

1. HTML annotations change the appearance of documents so users can see which links are in the TeleWeb cache before they are traversed.
   
2. Budget monitoring warns users when operations will exceed pre-specified limits.
   
3. Conditional actions allow users to postpone communication (and other actions). A batch queue is monitored, and URLs are automatically fetched when operating conditions are met.
   
4. Dynamic customization and configuration settings change values automatically as an effect of the changing conditions of use.

Mechanisms work together to provide an asynchronous, email-style of browsing in which the user can work disconnected by using a local cache, or trade off communication costs against information needs.

TeleWeb Architecture

• set browser proxy to localhost
• set browser cache to 0 kb
• set browser cache verify documents every time
• UI via browser: http://localhost/teleweb/foobar.html

Related Work

PDA Information Access

• Wireless World Wide Web [Bartlett95] & WWW PDA [Gessler94]

Notebook/Mobile Web Browsing

• Mobiscape [Baquero95] & Mowgli [Liljeberg95]
• Rover Toolkit [Joseph95] & InfoPad [Fox95]

Ubiquitous Computing

• How to program networked portable computers [Goldberg93]
• Adaptive Mobile Computing & Customizing Mobile Apps [Schilit91, Schilit93]

Commercial Products

• OpenMarket's Express & MilkTruck

Conclusions

• Ubiquitous information access in a WWW Setting
• Laptop/PDA with variable communication costs & connectivity
• Application adapts to system changes
• Goal is a high degree of predictability and control under variable conditions
• Key design ideas:
  
1. HTML annotations
   
2. Budget monitoring
   
3. Conditional actions
   
4. Dynamic customization and configuration settings
   
• Initial implementation on Linux based on the Harvest project's cached