Web Access for the Masses

Reference: Chapter 3 of WWWBTB

Contents:

Introduction
Overview of Internet Appliances
One Internet Appliance in Detail: Network Computers
Broadband Network Access

Introduction

Questions

6 billion people in the world; only 30 million Internet users
How will most people in the world access the Internet?

What devices? (TV set top boxes, ...)
What communication medium (ISDN, ...)

How will people get sufficient network bandwidth (e.g., downloading images)
Recent developments impacting these questions

US Telecommunications Bill of 1996, deregulating what local Bells can offer
Jan. 1998 petition by local bells to Circuit Court of Appeals to charge Internet service providers for their subscribers' use of phone lines while online. (Earlier, FCC rejected request.)

Internet Appliances

Overview: The Candidate Devices

NCs (Apple, IBM, Oracle, Netscape, Sun)
Mobile NCs
Network PCs (NetPCs)
Windows Terminals
TV set top boxes (WebTV, Philips, Sega, ...)
TVs with built-in electronics for Internet access
Phones and cell phones with displays (AT&T's PocketNet w/ Unwired Planet's HDML)
Personal Digital Assistants (PDAs) and Personal Information Managers
Two-way pagers

Some Challenges

Small displays (phones), low resolution displays (TV)
Intermittent network connections (mobile devices)
Possibly text-only display (cell phones)
Incompatible protocols (HDTP for cell phones) and document description languages (HDML for cell phones, HTML variants for TV set-top boxes)
Cost: lower price means more of the world's population will use it

High volume lowers manufactoring cost
Monitor prices must drop
Fewer ICs must be used (hence acquisitions in chip industry: National Semiconductor's single chip containing Pentium processor, 10/100Mbit/sec Ethernet, I/O, and power management)

Two Categories of Devices

Client is terminal: Download HDML to a cell phone
Cliant is full-fledged computer: Download Java program to NC

Network Computers

Overview

May 20, 1996: NC Reference Profile released
Write one app that runs on NCs from multiple vendors
NC from vendor A works with server from vendor B
Lower cost of ownership than PC

Sun: $2500 for Javastation vs. $12k for PC
IBM: $3144 for IBM NC vs. $5713 for PC

NC solution:

NC= processor + memory + monitor + network connection
IBM: Sealed case to prevent custom hardware mods
Server runs code, NC runs thin client
Load OS over network when device is powered on
NC can cache
All user files stored on server
All sys admin done centrally: backups, software updates, configuration

Down side:

Reliability
Network cost
Server cost

PC response:

"Zero Administration for Windows" initiative
Windows Terminals
NetPC spec

Potential uses for NCs:

Hospitals, banks, other high volume/low power users
Replacing dumb terminals

NC Reference Profile(Minimal features)

Execute Java VM
>= 4M RAM
VGA display
Pointing device
text input
audio output
Network interface
Ability to establish network service

run IP, use Ethernet or 25Mbit/sec ATM, ISDN
offer TCP, FTP, TELNET, NFS, UDP, SNMP, SMTP, POP3, IMAP4, HTTP
Get IP address via Dynamic Host Configuration Protocol (DHCP)
Boot via Bootp protocol

Optional: ISO 7816 SmartCard (e.g., for user id and preferences)
Apps:

Java Run Time Environment
Web browser
JPEG, GIF, WAV, AU formats can be presented

Mobile NC

on-persistent network connection
distinguish offline vs. online modes
tolerant of unreliable network connections - laptop in car with cell phone modem
categories of mobile NCs

Professional assistant (laptop) same capability as desktop NC
Information access device (palmtop) Less memory and CPU than prof. asst.
Basic device (PDA, phone) Just to keep in touch with the office

Architectural differences from desktop NC

Boot stand-alone (thus persistent storage containing "base code" - OS kernal and key apps [Web browser])
Distinct modes: off and on-line, plus mechanism to sychronize cached copy of data on mobile device with original copy on server
Proxy program on server that mobile devices talk to. Proxy

transforms or dstills data stream sent to mobile device to fit screen size/resolution and processing power
does protocol conversion (e.g., HTTP into more compact form for wireless)
security

Other Appliances

TV-top boxes ($199 for Sega to $349 for WebTV, with $20-$25 per month for connection)
Hybrid TV/PC (higher res than set-top box, one remote control, potentially lower cost due to integrated electronics). Uncertaintly in what price point/features consumers desire.
Telephones with displays

$500 in 1997
AT&T Pocket net:

send/receive email, view Web pages, send faxes
3 line by 22 char screen for text only
Cellular Digital Packet Data modem, 19.2 Kbit/sec
$45 activation fee over normal cell phone charge, $40 monthly fee for 500K bytes of data transmission, plus 8 cents per additional kilobyte
Web pages in HDML: Card model of page layout; ACCEPT and PREV keys.
Web pages delivered over HDTP from Unwired Planet

Broadband Public Networks

Cable Modems

Ethernet adaptor on PC connects to cable via Ethernet's RJ-45 connector
Downlink bandwidth: 500Kbps to 30Mbps
Upload bandwidth: could be by normal telephone modem; generally slower; up to 10Mbps with cable modem for upload
Cable modem contains tuner to separate data from rest of broadcast stream

Telephone networks

Challenge: deliver service over ancient twisted pair wiring

maybe with high data rate
maybe with concurrent voice service

Integrated Services Digital Network (ISDN)

Digitize the signal in your home (vs. an analog modem)
Digital signal means higher bandwidth
Almost instantaneous call placement
Two channel types:

B: 56 or 65 Kbits/sec
D: 16 Kbits/sec, for control and signaling (identify caller's phone number)
Can "band" two B channels to double data rate

Common service offerings:

B+D (for home use)
2B+D (for small office)
23B+D (T1: 1.544 Mb/sec) or 30B+D (2.048Mb/sec, in Europe/Japan):

You need Ethernet-to-ISDN adaptor or an ISDN adaptor for your computer
Problems:

There's a limit of distance between Telco's local office and customer premises (loop distance)
Installation cost: You need either

digital telephones if you want to give up your traditional analog phone line bill, or
additional wiring in your home/office

Assymetric Digital Subscriber Line (ADSL)

Much faster than ISDN
Can use plain old telephone service (POTS) over same wire simultaneously
ADSL carries 3 separate frequencies over same line:

POTS
upstream data channel: 15-640 Kbps data rate
downstream data channel: T1 to 9 Mbps

You need ADSL modem to use service. One modem port could be Ethernet.
Alternative: VDSL (Very-high-data-rate DSL)

13 to 55 Mbps
only operates over half the loop distance

Satellite

Avoids cost of new wiring to individual homes/offices
Great for developing counties with limited phone infrastructure
Great for industrialized countries with phone monopolies that offer high prices, poor service
Great for "push" technology
Downlink bandwidth: 400Kbps (Hughes Network System's DirectPC)
Still need phone for uplink

Concluding Remarks

Modem speeds today are far beyond what my data communication textbooks from 1992-1995 expected!
Surprising how long it's taking to offer fast home connections (cable modems, ISDN)
No clear winner in marketplace can be predicted:

Bill Gates with Craig McCaw (founder of McCaw Cellular) invested $9B in network of 840 low orbit satellites for world-wide coverage, but
Microsoft later invested $1B for cable company Comcast (4th largest in US)

Last modified on 22 January 1998 by abrams@vt.edu.