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Introduction to Management Information Systems Chapter 5: Data Communications and Internet Technology

This chapter provides an overview of the Internet and enterprise networks, including topics such as ISPs, Internet backbone, domain name systems, public IP addresses, issues with domain names, and the future of the Internet. It also discusses enterprise networks, including LANs, WANs, and types of WANs.

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Introduction to Management Information Systems Chapter 5: Data Communications and Internet Technology

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  1. Introduction to Management Information SystemsChapter 5 Data Communications and Internet Technology HTM 304 Fall 07

  2. Today – The Internet & Enterprise Network • Internet (Public) • Enterprise Network (Private)

  3. The Internet • Note: Capitalized “I”, the only one, public access • Also called “the Net” • “internet” = inter-connected networks (LANs or WANs)  there are many. • The Internet: A global WAN that connects approximately 1 million inter organizational computer networks in more than 200 countries on all continents • Origin: ARPANET – (DoD, 1969) • Original purpose  exchange messages, transfer files

  4. Connecting the Internet • ISP: Internet Service Provider • Name several well-known ISPs • How to find a local ISP: http://www.thelist.com • Internet Backbone • Providing connectivity in many cities • Has many network access points (NAPs) • Local ISPs rent NAPs to access the backbone • Who owns the backbone? • ARPAnet (DoD, 1969 – 1986) • NSFnet – educational (1986- now)

  5. Domain Name Systems (DNS) • To publish on the Internet:  Apply for a public domain name • Organization: ICANN (Internet Corporation for Assigned Names and Numbers, www.icann.org ), 13 root servers maintain lists of IP addresses of Internet servers • Purpose of Domain Name: • To get user-friendly names rather than IP addresses. • Components of a Domain Name: www.sina.com.cn • From the rightmost: Regional code  top-level domains (types of institutes)  name of the institute  www (or www2, the main server), or a specific computer in the domain

  6. The Naming System • Regional Code: • E.g. “cn”, “fr”, “de”, “it”, “uk”, “au”, “jp”, …etc. • What is the regional code for the United States? • Top-Level Domains (type of the site) • com / edu / gov / net, etc. • See page 143 for a complete list (note: in some country, .com is short as “.co”, e.g www.amazon.co.uk) • Name of the institute (e.g. csusm.edu, microsoft.com) • The leftmost: • www: world wide web – generally go to the predefined main server of the institute • A particular machine or subnet: • E.g. fangfang.csusm.edu, sandiego.craigslist.org

  7. Exercise: • Based on the following domain name, describe the type of the institute. • sandiego.craigslist.org • www.ebay.com.au • www.tsinghua.edu.cn

  8. Public IP address • Any computer with direct Internet Access needs a public IP address. • IPv4 and IPv6 • Some small business/home LANs only obtains one IP addresses for the router or server • Router has two IP addresses (one public, one private) • The other computers obtain private IP addresses from routers

  9. Issues with Domain Name System • Use Fake Domain Names to acquire users’ private information • Using similar names to gain visits • E.g. www.craiglist.com, www.wikipeda.org, www.goggle.com, etc. • Cybersquatting: register domain names in hoping companies would want it later: gauge for money. • Anti-cybersquatting Consumer Protection Act. Nov 1999.

  10. The future of the Internet • The current Internet is UNSATISFACTORY • Too slow for data intensive applications • Unreliable, insecure • Article: the internet is broken – call for a complete redesign • Three initiatives underway • Internet 2 Develops and deploys advanced network applications such as remote medical diagnosis, digital libraries, distance education, online simulation and virtual libraries. (http://www.Internet2.edu) • Next Generation Internet (NGI) Government sponsored initiative aimed at creating an Internet that is fast, always on, everywhere, natural, intelligent, easy and trusted. (http://www.ngi.gov ) • vBNS high-speed network designed to support the academic Internet2 and the NGI. Goal: 2.4 gigabits per second.

  11. Enterprise Networks • Major Components of Enterprise Networks • LANs – a small size network in a single location (e.g. a building). • Small company, home business, a department in a big organization (e.g. embedded LAN for large enterprise) • WANs – connects computers (or LANs) located at physically separated sites. (see Figure 5-12 on page 126) • Generally provided by common carriers (e.g. Verizon, AT&T, etc.) • Backbone Networks: high-speed central networks which connects multiple smaller networks (e.g. LANs or small WANs)

  12. Types of WANs • Connecting the PC to an ISP via Modems • Home computers, small businesses use • Telephone dial up, DSL line, cable TV line • Networks of Leased Lines (Mostly PSTN) • Lease from telephone companies (a variety of lines, speed ranges from 1.544Mbps to 40Gbps) • Connecting different sites of the company • Expensive, hard to manage, • sometimes, managed by specialized 3rd parties • Public Switched Data Network (PSDN) • PSDN – a network of computers and leased lines that is developed and maintained by a vendor • Lease a line from the vendor that connects to PSDN • Virtual Private Network (VPN) • Uses the public Internet (private internets sometimes) to create virtual connections

  13. Creating VPN • Tunneling Protocol: • Tunneling: encrypts the data packet to be sent, and places it inside another packet, which provides confidentiality, authentication and integrity of the message. • Ensure Security: software encryption. • Offer the benefits of leased lines, but more flexible. • The connections is established upon user request, disconnect at will • Good for employees on the go, small sites which is too expensive to lease fixed lines, or business partners with limited data transfer, etc. • Microsoft windows supports VPN

  14. Criteria for comparing network alternatives • Cost • Initial setup costs, operational costs, and maintenance costs • Performance • Speed, latency, availability, loss rate, transparency, performance guarantees • Other • Growth potential, commitment periods, management time, financial risk, technical risk

  15. Extensions of Enterprise Network • Intranet vs Extranet • Intranet: a network designed to serve the internal information needs to a single organization • Extranet: connects part of the intranets of different organizations and allows for secure communications among business partners over the Internet using virtual private networks (VPNs) Extranet Business partners access modules such as SCM, CRM, and B2B

  16. Subnet and Subnet Mask • a subnetwork or subnet is a range of logical addresses (e.g. IP addresses) that is assigned to an organization. • Subnet mask is a 32-bit sequence which is used in conjunction with IP address to determine whether the computer is in the subnet. • How? A bitwise “and” operation: IP address: 143.37.100.27  10001111.00100101.01100100.00011011 Subnet mask: 255.255.255.0  11111111.11111111.11111111.00000000 Bitwise “AND” operation  10001111.00100101.01100100.00000000 143. 37. 100. 0 How many IP addresses can give the same result?

  17. Some Other Subnet Masks • 11111111.11111111.11111111.00000000 (255.255.255.0) ~ supports 256 IP addresses • 11111111.11111111.11111110.00000000 (255.255.254.0) ~ supports how many IP addresses? • 11111111.11111111.11111111.10000000 (255.255.255.128) ~ supports how many IP addresses? • 255.255.255.254 ~ supports how many IP addresses? • If a company has 120 computers, how should the network administrator configure the subnet mask? • Step1: round up to 2n, (e.g. ~27=128) • Step 2: set all the n digits to be 0 from right to left, and the rest digits as 1 • e.g. 11111111.11111111.11111111.10000000 • Convert to decimal representation of the network address: 255.255.255.128

  18. Exercises A) what should be the subnet mask if the company has 1000 computers? • B) Are computer A and B in the same subnet? • Computer A: 143.37.100.27 • Computer B: 143.37.101.36 • Subnet Mask: 255.255.252.0 • C) Markstein Hall has both computer labs and offices. The network administrator needs to separate the computers in the labs and offices into two separate subnets. The plan is, • Lab computers occupy IP addresses 144.37.2.0~127 • Office computers occupy IP addresses 144.37.2.128~255 How should the subnet mask be configured?

  19. Assignment: the Internet is Broken • Read the article and write your thoughts on this issue on the blog site. • Answer the following questions and email the answer to fangfang@csusm.edu by Oct 11 before class starts • What is the basic flaw of the current Internet design according to David Clark? • Why nowadays, the basic design flaw has become a much bigger issue compared to the past? • Explain the saying that “humans are good at ignoring problems” use your own words. • July 2005, Pew Internet reported ______% of U.S. Internet users have reported having spyware or adware on their computers merely by visiting websites.

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