MD253 - E-Commerce

Module 1: A World ConnectedSpring 2003

The Internet, consumer devices, iTV

How the Internet Works

Telecom: an Industry in Crisis

Solving the Last Mile Problem

Mobile & Wireless

Emerging & Key Technologies

What is the Internet?• A Network of Networks

– TCP/IP - standard protocol for routing & transport

• A medium of exchanging all form of digital data– text, graphics, audio, video, programs, faxes

• An infrastructure for various services– e-mail (electronic mail)– WWW (world wide web)– FTP (file transfer protocol)– UseNet newsgroups– Games, EDI, etc.

How Many Online?

source: nua.ie

Region # OnlineEurope 190.91 millionAsia/Pacific 187.24 millionCanada & USA 182.67 millionLatin America 33.35 millionAfrica 6.31 millionMiddle East 5.12 millionWorld Total 605.60 million

AOLtv Ultimate TV

xboxMoxi TiVo

Replay

Lyra Samsung Media Center

BSkyB

XP Media Center

Smart Display

Transmission Speeds• Bandwidth

– measure of transmission speed / capacity

• Bits & Bytes– bit - smallest form of computer memory - 1 or 0– byte - 8 bits, roughly 1 character (Latin alphabet)

• How do we measure speeds?– bps - bits per second– Kbps - kilobit, thousands of bits per second– Mbps - megabit, millions of bits per second– Gbps - gigabit, billions of bits per second

Anatomy of a URL

• URL– Uniform Resource Locator (web address)

http://www2.bc.edu/~gallaugh/directory/file.html

application protocol(http is assumed by current browsers).Others: FTP, NNTP

host computer(others@ BC:agora,www)

domain name,top level domain

user ID

directory file

case sensitive

The DNS & IP Addresses• IP Address

– Unique number identifying Internet computers. Expressed as four numbers between 0 and 255.

– ex: www.bc.edu = 136.167.2.72 (32 bit address)– IPv6: 128 bit addressing, more efficient/faster, secure

• DNS - Domain Name Service– A distributed database used to translate host/domain names, into Internet

Protocol (IP) Addresses.

• Registry of an Internet domain name:– for com, net, org, over 60 firms (see icann.org for list)– for country-specific domains (.jp,.uk, .tv) fees vary widely (see icann.org for

list)

Network Interconnectionsdial-in

users (56.6 Kbps)dormusers

class/officeusers

dorm LAN office LANmodem pool

web serverwww2.bc.edu

BC Campus Network Backbone (10 Mbps)(IP #s 136.167.xxx.xxx domain)

Internet Leased Line through our ISPs (45 Mbps / T3)

The Internet

local ISPmicrosoft.comwhitehouse.gov

wireless

RR

TCP/IP

• TCP/IP - the Internet’s common language

• TCP - Transmission Control Protocol. Breaks up transmissions (e-mail messages, web pages, etc.) into packets of no more than about 1500 characters each, checks the integrity of incoming packets, and reassembles packets on the other end

• IP - Internet Protocol. Routes packets.

Packet Traffic

• What’s in a packet?– source address– destination address– error checking (checksum)– time to live– options (timestamp, record route, etc.)– your data!

A Packet Switched Network at Work

E-mail message:

Prof. Gallaugher,I just wanted to let you know that I got a job based on the stuff I learned in your class...

packet1

packet2

packet3

E-mail message:

Prof. Gallaugher,I just wanted to let you know ...

packet2

packet1

packet3

packet1

packet2

packet3

packet2

packet3

R

R

R R

R

R = router

US Internet Infrastructure

Source: lbrandt@nsf.govWatch Cable & Wireless’s backbone traffic at:traffic.cwusa.com

TCP vs. UDP

TCP - perfect transmission is critical (e.g. e-mail)TCP will request packets that are lost or

damaged

The Internet

UDP - low latency is critical (e.g. streaming audio, video)Latency matters - UDP will ignore packets that

don’t arrive on time or in good shape

The Internet

UDP = User Datagram Protocol

Circuit vs. IP TelephonyCircuit Switching

Internet Telephony (e.g. Vonage, Net2Phone)

IP Telephony over Private Networks (e.g. corporate VoIP, Qwest)

Guaranteed QoS (quality of service)

packets over the Internet, variable QoS

packets over private network, improved QoS

The Internet

Private IP Network

87% Decline in

InternationalDS-3

Pricing over the past two

years

Source: BandXChange

67% Decline in Domestic

DS-3 Pricing over the past two

years

Source: BandXChange

The Last Mile Problem• The contenders

– Cable Modems (cable firms)• Tech limits:congestion (shared capacity with local users)

– DSL (RBOCs & those leasing capacity)• Tech limits:distance (must be 3.5 miles from central office

for ADSL), home wiring limitations

– Terrestrial Fixed Wireless (WorldCom, Sprint, others)

• Tech limits: line-of-sight, rain fade, antennas, congestion

– GEO Satellite (Hughes, EchoStar)• Tech limits: slower transmission, latency, need dish, line-

of-sight, congestion

i-Mode’s Rocket Ride

Mobile Contrasts

Europe• poor technology• “walled gardens”• enormous capital

outlays

Japan• packet-switched,

always on, HTML standards, java

• open platform• 3G licenses offered

for free via “beauty contests”

Emerging Wireless Technologies• Wi-Fi

– 802.11b – LAN replacement, 11 Mbps, 150-300 ft., crowded, unregulated 2.4 GHz spectrum

– 802.11a (Wi-Fi 5) – 54 Mbps, similar range, less crowded 5 GHz spectrum, 802.11g – 54 Mbps, rev. compatible w/(b)

• Bluetooth– Cable replacement technology– 400-700 Kbps, 30-33 ft., unregulated 2.4 GHz spectrum

• UWB – Ultra Wide Band– 100 Mbps+, 30 ft., multiple spectra (licensed &

unregulated)• RFID

– Tracking, payment, bar-code replacement– Current high cost $1-$2+, privacy concerns