eCommerce Infrastructure

1. eCommerce Infrastructure

2. Technology Overview • Internet is the most obvious technology needed to conduct e-commerce • Other technologies are also required • Database software • Network switches and hubs • Encryption hardware and software • Multimedia support

3. Internet Design Principles • Interoperability • Systems using different client and server hardware/software work together. • Layering • Protocols work in layers building on each other: Ethernet…IP…TCP…HTTP • Simplicity • IP hides the complexity of having to deal with different kinds of network topologies, hardware, routers etc. • Uniform naming and addressing • 32-bit dotted quad addressing, e.g., 152.15.71.226 • End-to-end • The internal structure of the network is hidden from users and applications.

4. Packet-Switched Networks • Local and long distance telephone companies in the 1950s were early models for networked computers • Single paths were created to connect two parties together, called circuit switching

5. Packet-Switched Networks • The Internet uses Packet switching • Files and messages are broken down into packets, which are electronically labeled with their origin and destination • Packets travel from computer to computer along the network until they reach their destination • Each computer the packet encounters decides the best route towards its destination • The destination computer collects the packets and reassembles the data from the pieces in each packet

6. Packet-Switched Network and Message Packets

7. Open Architecture Philosophy of the Internet • Independent networks should not require any internal changes in order to be connected to the network • Packets that do not arrive at their destinations must be retransmitted • Router computers do not retain information about the packets • No global control exists over the network

8. Internet Protocols • Physical Layer • Multiple technologies and protocols used, e.g., Ethernet (10Mbps), Fast Ethernet (100Mbps) • Each lower level network handles its own routing, addressing, etc. • Transmission Control Protocol (TCP) • Controls the assembly of a message into smaller packets before transmission, and reassembles them once received • Reliable, ordered delivery (sending & receiving) of packets to application • No security • In Windows, winsock program handles both TCP/IP

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

10. Internet Protocol Suite • The Internet protocol suite is the set of communications protocols that implements the protocol stack on which the Internet and many commercial networks run.

11. Layers in the TCP/IP Model

12. Internet Protocols - continued • Internet Protocol (IP) • Responsible for delivering packets of data to their destination • Rules for routing packets from their source to their destination • No security services • IPv6 is the proposed successor to IPv4 whose most prominent change is the addressing. IPv4 uses 32-bit addresses (~4 billion addresses) while IPv6 uses 128-bit addresses (2128≈ 1039 addresses). Designed for faster routing. Allows multiple streams to the same IP address, e.g. audio, video, HTML • Although adoption of IPv6 has been slow, as of 2008, all United States government systems must support IPv6. (Wikipedia) • IPV6.org, IPng (IP Next Generation) • User (Universal or Unreliable) Datagram Protocol (UDP) • Programs on networked computers can send short messages sometimes known as datagrams to one another. • UDP gives applications access to IP facilities, plus some other features such as checksums for data integrity and port numbers identifying specific applications as the destination • No services for reliable or ordered delivery

13. 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

14. 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://bisom.uncc.edu/courses/eBusiness/index.asp protocol://domain_name/path_name

15. Internet Protocols - continued • Domain Name System (DNS) • 32-bit (4 sets of up to 3 digits each, from 0 to 255) numeric addresses used by IP to route packets (known as “Dotted Quad”) • e.g., 152.15.71.153 • DNS translates domain names to IP numeric addresses • Can move from machine to machine while keeping the same name • Several machines part of a single service can share the same name • Host.Domain.TopLevelDomain • e.g., bisom.uncc.edu (find IP address)

16. Internet Protocols - continued • Hypertext Transfer Protocol (HTTP) • A request/response protocol between clients and servers. • Responsible for transferring and displaying Web pages • Client opens a TCP connection to Web server • Transmits an HTTP header containing • HTTP command, e.g., GET, PUT, POST • Pathname to resource portion of the URL • Information authenticating the user • Information about acceptable document formats • Transport Layer Security (TLS) & Secure Sockets Layer (SSL) • Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols which provide secure communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers. There are slight differences between SSL 3.0 and TLS 1.0, but the protocol remains substantially the same. • Encrypts communications • Allows use of digital certificates to authenticate the server to the client • Typically, only the server is authenticated (i.e., its identity is ensured) while the client remains unauthenticated; this means that the end user (be that a person, or an application such as a web browser), can be sure of whom they are "talking" to. The next level of security—in which both ends of the "conversation" are sure of to whom they are "talking"—is known as mutual authentication. Mutual authentication requires public key infrastructure (PKI) deployment to clients. (Wikipedia)

17. Internet Protocols - continued • Simple Mail Transfer Protocol (SMTP) • Specifies the recipients and format of a mail message • Post Office Protocol (POP) • Responsible for retrieving e-mail from a mail server • Internet Message Access Protocol (IMAP) • Allows a local client to access e-mail on a remote server. • Competes with POP • Defines how a client program asks a mail server to present available mail • Allows user to • Download only selected messages, instead of all messages • View headers only • Create and manipulate mailboxes on the server

18. Internet Protocols - continued • File Transfer Protocol (FTP) • Transfers files between TCP/IP-connected computers • Uses client/server model • Displays and manipulates remote and local computer file directories

19. Internet Utility Programs • Packet InterNet Groper (Ping) • Tests the connectivity between two Internet hosts • Determines if the host is active • Works by sending “echo request” packets ("Ping?") to the target host and listening for “echo response” replies • Determines number of hosts (hops) between two specified hosts

20. Tracert and Other Route-Tracing Programs • TRACE RouTe (Tracert) traces the round trip path (route) of packets between a user’s computer and another computer on the Internet • Incorporates a Graphical User Interface (GUI) for a visual representation of the route • E.g. http://visualroute.visualware.com/

22. Internet Leverage by Country WORLD TOTAL USERS (AUG. 2003): 700,000,000 LEVERAGE = % OF INTERNET USERS ÷ % OF WORLD POPULATION

23. 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 at 56K takes 40 hours • at 7Mbps 19 minutes; • at 1 Gbps takes 8 seconds)

24. Bandwidth Chart OPTICAL • A COPPER

25. Connections • Network Access Points (NAPs) • The backbone of the Internet • Connected together by NAP backbone providers – “optical carriers” up to 39Gbps • Regional Network Operators • Local ISPs

26. 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 KOREA SOURCE: CISCO SYSTEMS

27. European Interconnection Structure SOURCE: CYBERGEOGRAPHY.ORG

28. Internet I Network Architecture SOURCE: LAUDON & TRAVER, p. 126

29. Connecting to the Internet Services Advanced Research Backbone Internet2, Abilene, Interplanetary Internet GigaPOPs CA NAP Chicago NAP DC NAP NY NAP Network Service Providers (NSP) Sprintlink Cable& Wireless UUnet AT&T Worldnet Verizon/ GTE Qwest NAPs, IXPs, Peering MAE east LINX London HKIX KIX Korea Top-tier ISP Internet Service Providers SOURCE: SAMIRCHATERJEE Price Lower tier ISPs

30. plastic jacket glass or plastic cladding fiber core Fiber Optics TOTAL INTERNAL REFLECTION

31. Fiber Optic Cables SOURCE: SURFNET.NL

32. Dense Wave-Division Multiplexing (DWDM) Multiple colors (frequencies) sent through the fiber at the same time, more than 100 Each color carries a separate signal Allows huge bandwidth

33. 1,400 OC-192, 128l 1,200 1,000 1 Terabit = OC-192, 80l 800 Single Fiber Capacity (Gigabits/sec) 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 Optical Fiber Capacity Growth World record ~ 16 terabits per second

34. Fiber Optic Lines in Central Philadelphia TELECOM HOTEL SOURCE: CYBERGEOGRAPHY.ORG

35. Submarine Cables in North East Asia SOURCE: ALCATEL

36. Submarine Cables in North East Asia

37. Africa-One Submarine Network SOURCE:AFRICAONE

38. Telstar 10 Satellite Coverage Protocols • A dbW = DECIBELS RELATIVE TO ONE WATT EIRP = EFECTIVE ISOTROPIC RADIATED POWER E.L. = EAST LONGITUDE SOURCE:LORAL SKYNET

39. BizarNet Satellite Coverage

40. Inter-Network Communications • Bridges connect similar networks • Gateways connect dissimilar networks • Routers buffer and forward/route communications to their destination • Brouters = bridge+router

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

42. Routers SIEMENS NORTEL 3COM CISCO

43. Web Clients and Servers • Client computers typically request services, including printing, information retrieval, and database access • Servers are responsible for processing the clients’ requests

44. Server responds Client makes requests Client-Server Model CLIENT (Often a Web browser) SERVER INTERNET

45. Message Flow Between a Web Client and Server

46. Web Client/Server Communication • Three-Tiered Client/Server • First tier is the client • Second tier is the Web server • Third tier are the applications and their databases (Figure 2-19)

47. N-Tier Architecture Optimized for web page delivery Coded for specific application Managed and tuned by DBA Achieves full separation of function and administration Huge number of simultaneous clients SOURCE: FOURNIER

48. InterShop Architecture SOURCE: INTERSHOP

49. Web Client/Server Communication • Request message consists of: • A request line containing a command (e.g., GET), resource name, protocol, version • Optional request headers containing additional information about the client and the request • An optional entity body to pass bulk information to the server

50. Server Response Message