1. Network, Internet and e-commerce
Session 4

2. IS Infrastructure Components: Networking
Both human and computer communication involve senders, a message to share, and receivers.
Network requires:
Sender and receiver
Transmission pathway
Rules/protocols for communication

3. Network and Telecommunications
Two or more interconnected computers or computing devices.
Telecommunications: transmittal of data and information
Allows communications over large distances
Network technologies bring about several improvements to business process
The exchange of information in any form over a network

4. Networking and Communication Trends
Convergence:
Telephone networks and computer networks converging into single digital network using Internet standards
Broadband:
More than 68% U.S. Internet users have broadband access
Broadband wireless:
Voice, data communication are increasingly taking place over broadband wireless platforms

5. Networking and Communication Trends……
Examples of these trends in organizations?
Why do managers need to be aware of these trends?

6. Communication Model

7. Transmission Modes Simplex Half duplex Full duplex One direction
e.g. Television
Half duplex
Either direction, but only one way at a time
e.g. police radio
Full duplex
Both directions at the same time
e.g. telephone

8. What is a computer network?
Two or more connected computers
Major components in simple network
Client computer
Server computer
Network interfaces (NICs)
Connection medium
Network operating system
Hub or switch
Router

9. Network Classification: Servers, Clients, and Peers
Host (serve up) data, databases, files, applications, Web sites, video, and other content for access over the network
Clients
Consume hosted resources
Peers (P2P)
Serve and consume resources, both a server and a client interacting with similar computers

10. Client/Server network
Nodes and servers share data roles
Nodes are called clients
Servers are used to control access
Database software
Access to data controlled by server
Server is the most important computer

11. Peer to peer networks (P2PN)
All nodes are equal
Nodes access resources on other nodes
Each node controls its own resources
Most modern OS allow P2PN
Distributed computing is a form
Kazaa
Torrent

12. Networking Hardware
Networks use variety of devices to connect computers and peripheral devices
Network interface card: connects through cable or wireless antenna to middle device
Middle device connects to LAN or WAN
Hub: central location to connect computers
Switch: controls direction of communications
Router: Connects Two or more network

13. Networking Hardware (continued)
Bridge: connects two networks
Router: routes data packets to next node
Repeater: amplifies or regenerates signals
Modem: translates communication signals form analog to digital and vice versa
Dial-up connection: slower type of connection through modem

14. COMPONENTS OF A SIMPLE COMPUTER NETWORK
Illustrated here is a very simple computer network, consisting of computers, a network operating system residing on a dedicated server computer, cable (wiring) connecting the devices, network interface cards (NICs), switches, and a router.

15. CORPORATE NETWORK INFRASTRUCTURE
Today’s corporate network infrastructure is a collection of many different networks from the public switched telephone network, to the Internet, to corporate local area networks linking workgroups, departments, or office floors.

16. IS Infrastructure Components: Types of Computer Networks
Usage
Size
Personal area network (PAN)
Wireless communication between devices (Bluetooth)
Under 10 meters
Local area network (LAN)
Sharing of data, software
applications, and other resources between several users
Typically a building
Wide area network (WAN)
Connect multiple LANs, distributed
ownership and management
Large physical distance, up to worldwide
Networks are typically used to connect devices within an organization, or across organizational subunits.
Increasingly, LANs are becoming wireless (WLANs) using high-frequency radio-wave technology; WLANs are also referred to as Wi-Fi networks (wireless fidelity). These are easier to install, as there is no need for cabling.
Wide area networks can range from spanning multiple buildings (sometimes called a campus area network) to covering the area of a city (sometimes called a metropolitan area network) to worldwide (the Internet).

17. Network Topology Logical layout of wires and equipment Choice affects
Network performance
Network size
Network collision detection

18. BUS Also called linear bus One wire connects all nodes
Terminator ends the wires
Advantages
Easy to setup
Small amount of wire
Disadvantages
Slow
Easy to crash

19. STAR All nodes connect to a hub Packets sent to hub
Hub sends packet to destination
Advantages
Easy to setup
One cable can not crash network
Disadvantages
One hub crashing downs entire network
Uses lots of cable
Most common topology

20. RING Nodes connected in a circle Tokens used to transmit data
Nodes must wait for token to send
Advantages
Time to send data is known
No data collisions
Disadvantages
Slow
Lots of cable

21. MESH All computers connected together Internet is a mesh network
Advantage
Data will always be delivered
Disadvantages
Lots of cable
Hard to setup

22. TREE Hierarchal Model Advantages Scaleable Easy Implementation
Easy Troubleshooting

23. Network Media Links that connect nodes Choice impacts Speed Security
Size

24. Twisted-pair cabling Most common LAN cable
Called Cat5, Cat 6 or 100BaseT
Four pairs of copper cable twisted
May be shielded from interference
Speeds range from 1 Mbps to 10,000 Mbps

25. Coaxial cable Similar to cable TV wire One wire runs through cable
Shielded from interference
Speeds up to 10 Mbps
Nearly obsolete

26. Fiber-optic cable Data is transmitted with light pulses
Glass strand instead of cable
Immune to interference
Very secure
Hard to work with
Speeds up to 100 Gbps

27. Wireless Media Data transmitted through the air LANs use radio waves
WANs use microwave signals
Easy to setup
Difficult to secure

28. Wireless Local Area Network
LAN using wireless technology to connect computers or workstations
Located within range of network
Security vulnerabilities
Open architecture; difficulty keeping intruders out

29. What is the Internet?
A world-wide network of computers allows people to share information electronically
Like a BIG book with many web-pages on different topics
Can be accessed anywhere with an Internet connection

30. How you access to Internet ?
A company that provides Internet access for customers (examples: World link , Mercantile , NTC )
Your computer connects to the Internet Service Provider (ISP), then to the Internet
Your computer
ISP
Internet

31. The Internet and the World Wide Web (WWW)
The Internet is one of several global networks
The Internet has standard protocols
The Internet is based on internetworking, or combining networks to form larger networks
The World Wide Web uses the Internet
The World Wide Web is not the Internet
The World Wide Web is
Web protocols (e.g., HTML and HTTP)
Web pages (documents containing HTML )
Web servers (store and provide access to Web pages via a Web site)
Web browsers (provide users with an interface to Web pages)

32. The Internet and the World Wide Web: Web Domain Names and Addresses
Uniform Resource Locator (URL) is used to identify and locate a particular Web page
Domain name is a term that helps people recognize the company or person
Prefix, like “google” or “microsoft”
Suffix, like .com, .edu, .org, .gov, or two-letter country codes
Dissecting a URL.

33. The Internet and the World Wide Web: IP Addresses
The Internet uses IP addresses
IPV4: Old style, 32-bit, running out of addresses
IPV6: New style, 128-bit, huge address space
The WWW translates domain names into IP addresses
translates to (IPV4) A URL could be expressed directly as an IP address, although it’s more common to use domain name.
The Internet uses a numeric addressing approach computers can understand. The old style of address was IPv4, which is running out of addresses and is slowly being replaced by IPv6, which has many more possible addresses and would allow for assigning a unique address to every grain of sand in the world.
The World Wide Web uses domain names as an addressing technique, and then translates requests for domain names into the IP addresses.
In addition to specifying the address of the Web server, URLs typically also include the path to the requested resource, such as a particular page located in a particular directory (e.g.,

34. The Internet and the World Wide Web: World Wide Web Architecture
Components
Interconnected Web servers
Utilize Transmission Control Protocol/Internet Protocol (TCP/IP)
Communicate over the Internet
Clients request Web page hosted on server
Server breaks into packets
Packets stream over internet to client
Client reassembles
Client can request retransmission of any missing packets
Web browser translates Web page into visible output
PACKED SWITCHED NETWORKS

35. Packet switching
Method of slicing digital messages into parcels (packets), sending packets along different communication paths as they become available, and then reassembling packets at destination
Previous circuit-switched networks required assembly of complete point-to-point circuit
Packet switching more efficient use of network’s communications capacity

36. PACKED-SWITCHED NETWORKS AND PACKET COMMUNICATIONS
Data are grouped into small packets, which are transmitted independently over various communications channels and reassembled at their final destination.

37. Switching technique
Circuit switching: dedicated channel established for duration of transmission
Packet switching: message broken into packets
Packet: group of bits transmitted together
Frame relay: high-speed packet-switching protocol used in WANs
Variable-sized packets routed quickly

38. Circuit Switched Technology
Connection is established between 2 devices on a network before they begin transmitting
Bandwidth is dedicated to this connection and remains available only to the source and destination devices until the connection is terminated
During connection all data follows the same path 1st selected by the switch or other connectivity device

39. Circuit Establishment

40. The Internet and the World Wide Web: Extranets and Intranets
Companies have confidential data
These data still need to be shared on a limited basis
Intranet: password-protected Web site designed for sharing within the company
Extranet: password-protected Web site designed for sharing with select partners
Data and communication are protected via firewalls and virtual private networks (VPNs)
Companies that want to share private data using the Internet create intranets for internal use and extranets for use by themselves and partner organizations.
These protected Web sites allow wide sharing but with security to ensure data only reach the intended audience.

41. The Internet and the World Wide Web: Extranets and Intranets
Intranet architecture
Extranet architecture

42. Virtual Private Network using the Internet
Why do organizations use VPNs?
When is using a VPN a good idea?
Laudon & Laudon, fig. 7-14
This VPN is a private network of computers linked using a secure “tunnel” connection over the Internet. It protects data transmitted over the public Internet by encoding the data and “wrapping” them within the Internet Protocol (IP). By adding a wrapper around a network message to hide its content, organizations can create a private connection that travels through the public Internet.

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