IP Addresses

1
IP Addresses

• Each computer on the internet has a unique
  address called an IP address , e.g.,
  24.246.122.10. All resources on the Internet must
  have an IP address--or else they're not on the
  Internet at all.
• Every IP address consists of two parts, one
  identifying the network and one identifying the
  node
• However, most people connecting to the Net get a
  different IP address every time they connect.
  That's because ISPs and organizations like AOL
  assign addresses dynamically in order to use the
  limited block of IP addresses given to them more
  efficiently. When an AOL customer connects, AOL
  assigns them an IP address. And when they
  disconnect, AOL makes that IP address available
  to another customer.

2
Domain Name System (DNS)

• Relates domain names with which we are familiar
  (e.g., www.cba.nau.edu) to IP address ( )
• Domain name is translated from right to left
• edu top-level domain
• Nau NAU domain
• CBA CBA domain
• WWW which CBA host
• Domain Name System servers are used to translate
  between Domain name and IP address

3
Structure of DNS Naming Hierarchy
4
Internet Protocols -- TCP/IP

• Messages are broken into packets of data which
  are sent across network
• Each packet contains
• Source address
• Destination address
• Sequencing information
• Error-control information
• Data
• Routing computers
• Move packets across Internet
• Packets not sent directly, could pass through
  many routers
• If one part of Internet fails, rest can still
  function

5
Other Internet Protocols

• FTP File Transfer Protocol
• POP Post Office Protocol
• SMTP Simple Mail Transfer Protocol
• MIME Multimedia Internet Mail Extensions
• HTTP Hypertext Transmission Protocol
• HTTPS Hypertext Transmission Protocol Secure

6
Internet Servers

• Web (e.g.,WWW.CBA.NAU.EDU)
• E-Mail (e.g., Groupwise sever)
• Database (e.g., Oracle server)
• File (e.g., Bart)

7
Web Hardware

• Client computers
• Server computers
• Communications media used to connect computers

8
Server Hardware

• Multiprocessors and/or duplicate processors
• Reliable and redundant data storage using
• SAN (Storage Area Network) distributed data
• Mirroring
• Fault Tolerance
• High Speed pathways (Fiber channels)

9
Communications media

• Way that digital equipment is connected/communicat
  es
• Measured in bandwidth
• How much data can be transferred at a given time
• High bandwidth more data
• Measured in bits per second (bps), kilobits per
  second (Kbps) or megabits per second (Mbps)

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Types of media

• Copper wire
• Widely used, widely available, reliable and easy
  to install
• Inadequate for high speed data transmission
• Fiber-optic cable
• Thinner and lighter than copper, higher bandwidth
• Coaxial cable
• Microwave/satellite
• May require repeaters to boost/regenerate signal

11
Types of Connections

• Dial-up phone line
• Cable modem shares cable coax connection by
  splitting available bandwidth into TV and data
• DSL uses existing phone lines by splitting
  bandwidth into voice and data, but has
  significant distance limitation (signal degrades over distance miles
• Satellite uses existing satellite TV connection
  by splitting bandwidth into TV and data section
• ISDN special phone service that provides both
  data and voice channels
• Large businesses have much higher speed options
  such as fiber and/or T1 circuit

12
Limited options for connection

• Web TV use your TV as an internet connection
  service includes keyboard and permits browsing of
  Web, Email, and Chat
• PDAs with wireless connection service includes
  browsing of Web and Email

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Communications Comparison
14
Flagstaff Services (sources Getspeed.com and
Cablevision.com)
15
Connection of computer to communications media
requires

• Modem to convert from digital which is
  binary(bits) to
• Analog (copper wire)
• Optic pulse (fiber optic)
• TV-type signal (coax)

16
Internet Service Providers

• Used by most home users
• Sometimes defined by type of communications
  connection (e.g., cable and satellite)
• Charge monthly fee of about 20
• Large businesses may have their own connection to
  Internet (e.g., NAU, etc.)

17
ISP Rankings as of 3/31/2001
18
Server Software

• Operating System manages resources on server
  computer
• Most are
• Multiuser allow more than one user
• Multitasking allow more than one application to
  run at a time
• Multithreading Allows multiple activities to be
  performed at the same time in parallel
• Web Server Basics

19
Specific Operating Systems

• Unix (Linux) originally invented by Bell
  Laboratories in 1960s
• Different versions, provided by different vendors
  Solaris (Sun), AIX (IBM), Linux (Redhat,
  Caldera, Apache, and others)
• Microsoft Internet Information Server (IIS)
• Others, Novell,
• Comparison of Web Server Software

20
Database Servers

• Oracle
• DB2 (IBM)
• Microsoft SQL Server
• Access, Sybase, Informix, and others

21
Web Server Requirements

• Reliable 24/7
• Scalable capable of handling peak loads
• Have a high-speed connection to Internet
• Have a high-speed connection to online monetary
  transaction processing system
• Round-the-clock operations and support

22
Alternatives to doing your own hosting

• Use ASP (Application Service Provider) or ISP to
  host your site
• Hire someone to construct your site
• Set up your site under a portal (e.g., Yahoo) or
  existing store (Amazon)
• Pros and Cons of Outsourcing Server