1. MD253 / MK253 Electronic Commerce April 19, 2006 Telecom How the Internet Works Telecommunication Markets

2. 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

3. 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)

4. 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 name, top level domain user ID directoryfile case sensitive

5. 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)

6. Network Interconnections dial-in users (56.6 Kbps) dorm users class/office users dorm LANoffice LANmodem pool web server www2.bc.edu BC Campus Network Backbone ( 1 Gbps) (IP #s 136.167.xxx.xxx domain) Internet Leased Line through our ISPs ( 100 Mbps) The Internet local ISP google.com whitehouse.gov wireless R R stanford.edu

7. 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.

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

9. 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

10. US Internet Infrastructure

11. Portions of the Abilene Intenet2 Backbone

13. Circuit vs. IP Telephony Circuit Switching Internet VoIP (e.g. Vonage, AT&T CallVantage, Skype) Private Network VoIP (e.g. corporate VoIP) Guaranteed QoS (quality of service) packets over the Internet, variable QoS packets over private network, improved QoS The Internet Private IP Network

15. Words from the Powerful VoIP is the most significant paradigm shift in the entire history of modern communications since the invention of the telephone. 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. Former FCC Chair Michael Powell Time Warner CEO Richard Parsons