e Commerce Technology 20 751 Lecture 2 The

e. Commerce Technology 20 -751 Lecture 2: The Internet

Ecommerce Statistics • Web traffic doubles every 98 days – The number 1 becomes 4 billion in 8 years • Ecommerce activity doubles every year – U. S. (1999) $130 billion • B 2 B exceed B 2 C by a factor of 6; will go up to 14 – Does not include • foreign exchange ($2 T/day) • interbank ($2 T/day) • securities ($100 B/day) – By 2003, global ecommerce $3. 2 T, 10% of world economic product

Internet Host Count 1995 -2000 80, 000 HOST = DOMAIN NAME FEBRUARY 2000 72, 400, 000 70, 000 60, 000 New survey data 50, 000 40, 000 Adjusted old survey data 30, 000 20, 000 10, 000 0 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 SOURCE: NGI

Projected Internet Host Count Historical 1 BILLION AUG. 2005 100 MILLION JAN. 2001 10 MILLION JAN. 1996 1 MILLION JUL. 1992 Projected CURRENT SOURCE: NGI

Bandwidth Review • Bit (b) = a unit of information, 0 or 1 – 10 bits can represent 1024 different messages – 20 bits represent > 1 million – 30 bits > 1 billion messages • The bandwidth of a communication channel = number of bits per second it transmits • All channels have limited bandwidth • One byte (B) = 8 bits (an octet) • Transmitting 1 MB at 56 K bps takes 143 sec. • 1 GB = gigabyte takes 40 hours – at 7 Mbps 19 minutes; at 1 Gbps takes 8 seconds) • Latency = delay from first bit transmitted to first received

Bandwidth of a Truck • Semi Tractor-Trailer 30’L x 10’H x 8’W 2500 ft 3 • DVDs (Digital Videodisks) – @5 GB each, 2000 GB (2 terabytes)/ ft 3 – Semi holds 5 million GB = 5 petabytes (enough to store every book ever published) • Pittsburgh - San Francisco 3000 miles – @ 50 miles/hour = 60 hours 200, 000 seconds – Bandwidth 25 GB / second 200 gigabits/sec 200 times the bandwidth of gigabit Ethernet! • Problem: latency = 60 hours

BANDWIDTH 1 terabit APPLICATION TECHNOLOGY Experimental All U. S. telephone conversations simultaneously 1 gigabit Full-motion HDTV OC 12 = 622 Mb FDDI OC 3 = 155 Mb Virtual Reality, Medical Imaging Video Conferencing, Multimedia DSL ~ 7 Mb Streaming Video + Voice T 1/E 1 Copper Browsing, Audio New Modem 56 K In Kbps ADSL ISDN 128 K Fiber T 3/E 3 T 3 = 44. 7 Mb T 1 = 1. 544 Mb Gigabit Ethernet E-mail, FTP 19. 2 Old Modem Telnet 4. 8 Human speech = 30 bps Wireless WAN Paging BANDWIDTH LIST

Dense Wave-Division Multiplexing 1, 400 OC-192, 128 l 1, 200 1 Terabit = 1, 000 Single Fiber Capacity (Gigabits/sec) OC-192, 80 l 800 600 OC-192, 48 l 400 200 565 Mb 1. 7 Gb OC-48 19 83 19 84 19 85 19 86 19 87 19 88 19 89 19 90 19 91 19 92 19 93 19 94 19 95 19 96 19 97 19 98 19 99 0 135 Mb OC-192, 32 l OC-48, 96 l OC-192, 16 l OC-48, 40 l OC-192, 2 l OC-192 20 -751 ECOMMERCE TECHNOLOGY SUMMER 2000 COPYRIGHT © 2000 MICHAEL I. SHAMOS

LINK Population Per Internet Host Computer

Structure of the Internet NAP Europe Backbone 1 NAP Backbone 4, 5, N Japan Regional A Backbone 2 NAP Backbone 3 Australia Regional B MAPS UUNET MAP SOURCE: CISCO SYSTEMS

Internet Backbone Structure • Level 1 (interconnect level, NAPs) – billions of pages per day • Level 2 (national backbone, MAE, FIX) – Federal Internet e. Xchange Points – Peering agreements: connect, share routing info) • Level 3 (regional providers, state level) • Level 4 (local ISP) • Level 5 (companies, individuals)

Network Access Points (NAP) • Where Tier 1 networks interconnect – – – Chicago (Ameritech) MAE West, Pac Bell New York NAP (Sprint) MAE East (MSF), CIX Minneapolis Seattle • NAP Connection Process • Tier 2 MAEs (Metropolitan Area Ethernets): – Houston, Dallas, LA, Big East (ICS) • Exchange Point information • European Exchange Points

e. Commerce is 24/365 MAE East Aggregate Input Traffic: Tuesday, Nov. 23, 1999 Traffic through a major Network Access Point (NAP) 24 -hour cycle Peak: 2260 Mbps 4: 00 p. m. EDT Megabits/second Low: 1180 Mbps 4: 15 a. m. EDT

Satellite Access (Inter. Sat. Com)

World Internet Population 9/99 • World Total • Africa 201 MILLION 2 million • Asia/Pacific 34 million • Europe 47 million • Middle East • Canada & USA • Latin America 1 million 112 million 5 million SOURCE: NUA INTERNET SURVEYS

Web Availability Requirements REQUIRED UPTIME PERMISSIBLE DOWNTIME Beta Test Most commercial systems Mission-critical systems Real-time Carrier-quality systems 20 -751 ECOMMERCE TECHNOLOGY SUMMER 2000 COPYRIGHT © 2000 MICHAEL I. SHAMOS

Plain Old Telephone System (POTS) Communication requires a series of dedicated lines from point A to B A This network is CIRCUIT-SWITCHED Each person can talk to one other person at a time B Capacity is tied up for the entire call even if no one is talking Also true of cellular phones If one link fails, communication is lost

Network • Two or more computers connected together: • Allows – – exchange of data separation of function (accounts receivable v. payroll) shared services (printers, databases) reliability • Requires – interconnection (wire, fiber, infrared, radio) – communication protocols

Network Topologies • More than two computers causes complications: 1 2 3 4 LAN BUS TOPOLOGY 5 LAN = LOCAL AREA NETWORK • Each machine on a network must have a unique address • If machine 2 sends a message to machine 4, what tells 1, 3 and 5 to ignore it, but 4 to listen? • Ethernet protocol. Demo.

Routing Machine 35 wants to send a packet to Machine 249. Machine 2. 16 Routers determine the path the packet will take. Machine 1. 35 Machine 3. 249 B A Router A can send the packet either way NUMBER OF ROUTES ROUTING STATISTICS 20 -751 ECOMMERCE TECHNOLOGY 4. 1 NETWORK 4 & IT’S ROUTER SUMMER 2000 5. 9 COPYRIGHT © 2000 MICHAEL I. SHAMOS

Routers NORTEL 3 COM CISCO 20 -751 ECOMMERCE TECHNOLOGY SUMMER 2000 COPYRIGHT © 2000 MICHAEL I. SHAMOS

Packet Switching (TCP/IP) TCP = TRANSMISSION CONTROL PROTOCOL (Breaks messages into packets and reassembles them) IP = INTERNET PROTOCOL (Moves packets around the Internet) DEMO SOURCE: J. DECEMBER

The Internet IPP = Internet Presence Provider (PNC Bank, CMU) ISP = Internet Service Provider (AOL, Mind. Spring, Verity) SOURCE: ECKMAN ENTERPRISES

Internet Performance • • The Internet is heavily instrumented Its performance is constantly monitored Internet traffic report AT&T network status

Client/Server Architecture • • Fundamental Internet structure Client requests service; server provides it Data exchanged only through real-time messages Server may become a client to a different server 1 Server 2 responds to client 1 Client 1 requests service from server 2 The Internet 2 Client 2 requests service from server 3 3 Server 3 responds to client 2 20 -751 ECOMMERCE TECHNOLOGY SUMMER 2000 COPYRIGHT © 2000 MICHAEL I. SHAMOS

IP Addresses • Machines on the Internet need an addressing scheme (or couldn’t receive packets!) • Each machine has a 32 -bit address assigned by the Internet Corporation for Assigned Names and Numbers (ICANN). • In the U. S. , American Registry for Internet Numbers (ARIN) • In Europe, Réseaux IP Européens (RIPE) • Addresses are written in dotted decimal notation: 128. 2. 218. 2 1000000010 11011010 00000010 • Current max number of IP addresses = 232 ~ 4, 000, 000

Domain Names • IP addresses are inconvenient to remember 128. 2. 218. 2 v. euro. ecom. cmu. edu (fully qualified) • Domain names are alphanumeric aliases for IP addresses. They form a tree structure of FQDNs: ROOT. GOV AMAZON . COM MCKINSEY . MIL YAHOO . NET . EDU CMU PITT . ORG . IT MIT 208. 216. 182. 15 207. 237. 113. 94 GSIA YEN CS ECOM EURO 128. 2. 218. 2 HEINZ DOLLAR PESO 128. 2. 218. 4

Converting Domain Names to IP Addresses • • IP addresses track topology (physical location). Domain names track administrative responsibility. There’s no conversion formula. Has to be looked up! DNS (Domain Name System) is a distributed database of names • Network servers maintain tables of domain names. • IP addresses are obtained by resolvers that communicate with nameservers on the net

DNS Resolution of “abc. foo. com” What is the IP address of abc. foo. com? Root DNS 202. 168. 14. 12 . com DNS client Try. com Try foo. com DNS Local DNS Resolver + Cache SOURCE: CISCO SYSTEMS abc. foo. com is 202. 168. 14. 12

URL: Uniform Resource Locator • URL identifies a specific resource on a server in a domain • URL tells what protocol to use to access the resource • URL format: http: //euro. ecom. cmu. edu/program/courses/index. shtml protocol: //domain_name/path_name

Other URL Protocols • • • https: ftp: mailto: telnet: news: irc: finger: gopher: archie: (secure, encrypted HTTP) (file transfer protocol) (email) (remote login) (obtain Usenet news) (Internet Relay Chat) (obtain information about a user) (indexes of text files) (ftp databases)

Browser • Implements HTTP (Hyper. Text Transfer Protocol) – Displays web pages – Access authentication – Caching, freshness control • • Font mapping, e. g. Unicode Compression, decompression Handles multimedia, manages plug-ins Interprets scripts Executes Java applets Maintains cache, history Manipulates cookies

Q&A 20 -751 ECOMMERCE TECHNOLOGY SUMMER 2000 COPYRIGHT © 2000 MICHAEL I. SHAMOS