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eCommerce Technology 20-751 Lecture 2: The Internet

eCommerce 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 B2B exceed B2C by a factor of 6 ; will go up to 14 Does not include

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eCommerce Technology 20-751 Lecture 2: The Internet

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  1. eCommerce Technology20-751Lecture 2: The Internet

  2. 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 • B2B exceed B2C by a factor of 6; will go up to 14 • Does not include • foreign exchange ($2T/day) • interbank ($2T/day) • securities ($100B/day) • By 2003, global ecommerce $3.2T, 10% of world economic product

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

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

  5. 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 56K bps takes 143 sec. • 1 GB = gigabyte takes 40 hours • at 7Mbps 19 minutes; at 1 Gbps takes 8 seconds) • Latency = delay from first bit transmitted to first received

  6. Bandwidth of a Truck • Semi Tractor-Trailer30’L x 10’H x 8’W  2500 ft3 • DVDs (Digital Videodisks) • @5 GB each, 2000 GB (2 terabytes)/ ft3 • 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/sec200 times the bandwidth of gigabit Ethernet! • Problem: latency = 60 hours

  7. BANDWIDTH APPLICATION TECHNOLOGY 1 terabit Experimental All U.S. telephone conversations simultaneously 1 gigabit Gigabit Ethernet Full-motion HDTV OC12 = 622 Mb FDDI Fiber OC3 = 155 Mb Virtual Reality, Medical Imaging T3/E3 T3 = 44.7 Mb ADSL Video Conferencing, Multimedia DSL ~ 7 Mb T1/E1 Streaming Video + Voice ISDN T1 = 1.544 Mb 128K Copper Browsing, Audio New Modem 56K E-mail, FTP 19.2 In Kbps Old Modem Telnet 4.8 Wireless WAN Paging BANDWIDTH LIST Human speech = 30 bps

  8. 1,400 OC-192, 128l 1,200 1,000 OC-192, 80l 800 600 OC-192, 48l 400 OC-192, 32l OC-48, 96l OC-192, 16l 200 OC-48, 40l OC-192, 2l 565Mb 1.7 Gb OC-48 OC-192 135Mb 0 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Dense Wave-Division Multiplexing 1 Terabit = Single Fiber Capacity (Gigabits/sec)

  9. Population Per Internet Host Computer LINK

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

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

  12. 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

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

  14. Satellite Access(InterSatCom)

  15. World Internet Population 9/99 • World Total201 MILLION • Africa 2 million • Asia/Pacific 34 million • Europe 47 million • Middle East 1 million • Canada & USA 112 million • Latin America 5 million SOURCE: NUA INTERNET SURVEYS

  16. Beta Test Most commercial systems Mission-critical systems Real-time Carrier-quality systems Web Availability Requirements PERMISSIBLE DOWNTIME REQUIRED UPTIME

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

  18. 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

  19. Network Topologies • More than two computers causes complications: • 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. 1 2 4 5 3 LAN = LOCAL AREA NETWORK LAN BUS TOPOLOGY

  20. Machine 2.16 Machine 3.249 Routers B A Machine 1.35 4.1 5.9 NETWORK 4 & IT’S ROUTER NUMBER OF ROUTES ROUTING STATISTICS Routing Machine 35 wants to send a packet to Machine 249. Routers determine the path the packet will take. Router A can send the packet either way

  21. Routers NORTEL 3COM CISCO

  22. 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

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

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

  25. Server 2 responds to client 1 2 Client 1 requests service from server 2 1 Client 2 requests service from server 3 The Internet 3 Server 3 responds to client 2 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

  26. 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 10000000 00000010 11011010 00000010 • Current max number of IP addresses = 232 ~ 4,000,000,000

  27. 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 .COM .MIL .NET .EDU .ORG .IT CMU PITT MIT AMAZON MCKINSEY YAHOO 208.216.182.15 207.237.113.94 GSIA CS ECOM HEINZ YEN EURO DOLLAR PESO 128.2.218.4 128.2.218.2

  28. 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

  29. client DNS Resolution of “abc.foo.com” What is the IP address of abc.foo.com? Root DNS 202.168.14.12 .com DNS Try .com Try foo.com foo.com DNS Local DNS Resolver abc.foo.com is 202.168.14.12 + Cache SOURCE: CISCO SYSTEMS

  30. 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

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

  32. Browser • Implements HTTP (HyperText 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

  33. Q A &

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