MD253 / MK253
Electronic Commerce
April 19, 2006
Telecom
How the Internet Works
Telecommunication Markets
Issues Covered
• How the Internet Works
– IP addresses, TCP/IP, packet switching, and why
you should care
• Telecom markets
– RBOCs, Cable, CLECs, VoIP, and more
– Crushing monopolies, shifting billions in wealth
The Transmission Speed Crib Sheet
• 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
Tbps – terabit, trillions of bits per second (a.k.a wicked fast)
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
(others
@ BC:
agora,
www)
domain user
ID
name,
top
level
domain
directory
case sensitive
file
The DNS & IP Addresses
• IP Address
– Unique number identifying Internet computers. Expressed
as four numbers between 0 and 255.
– ex: www.bc.edu = 136.167.2.96 (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 Interconnections
dial-in
web server
www2.bc.edu users (56.6 Kbps)
modem pool
R
dorm
users
dorm LAN
class/office
users
office LAN
wireless
BC Campus Network Backbone (1 Gbps)
(IP #s 136.167.xxx.xxx domain)
Internet Leased Line through our ISPs (100 Mbps)
The
Internet
stanford.edu
google.com
whitehouse.gov
local ISP
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
packet1
R
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
packet2 R
packet3
packet3
R
R
= router
R packet1
R
packet2
packet2
packet3
packet3
E-mail
message:
Prof. Gallaugher,
I just wanted to
let you know ...
US Internet Infrastructure
Portions of the Abilene
Intenet2 Backbone
Circuit vs. IP Telephony
Circuit Switching
Guaranteed QoS (quality of service)
Internet VoIP (e.g. Vonage, AT&T CallVantage, Skype)
packets over the Internet, variable QoS
The Internet
Private Network VoIP (e.g. corporate VoIP)
packets over private network, improved QoS
Private IP Network
Words from the Powerful
VoIP is the most
significant paradigm shift
in the entire history of
modern communications
since the invention of the
telephone.
Former FCC Chair Michael Powell
Employees ask me what
I’m most excited about
and I tell them Voice over
the Internet. It is going to
be a really big deal for us.
Time Warner CEO Richard Parsons