Transcript HTM304-Review2

Review Session
• Chapter 5 Networking
• Chapter 6 System Development
Chapter 5 Data Communications
and Internet Technology
• 5-layer network architecture
• The Internet and related
concepts
• Enterprise Networks / Subnet
• Wireless Technologies
5-layer architecture
Read: page 119 ~ 121 for details.
Figure 5-4 (page 119)
Understand how the 5 layers work together
Computer A
Applicati
on Layer
Layer 1: physical connectivity. Road and buses
Layer 2: how to communicate with your neighbors (control traffic and reduce
error of physical layer) truck-driver: deliver the package to the next station.
Layer 3: an overall connectivity map + routing algorithm. Allow connectivity of
one network to another. Logistic manager (knows how to connect all the transit
stations, and inform the truck driver where to send the mail to the next transit
station)
Layer 4: establish end-to-end connectivity between any two computers (may not
be in the same network, connected by the 3rd layer) clerk (receive your mail,
and notify you whether the mail can be sent through)
Layer 5: allow software (application programs) to talk to each other once layer 4
connection is established. Correspondents
End-to-end
Transport
Layer
Internet
Layer
Data Link
Layer
Physical
Layer
Point-topoint
Applicati
on Layer
Transport
Layer
Internet
Layer
Internet
Layer
Data Link
Layer
Data Link
Layer
Physical
Layer
Physical
Layer
Router A
Computer B
Router N
Point-topoint
Internet
Layer
Data Link
Layer
Physical
Layer
Understand how data is converted to electric signals
Break into pieces, add header data control of each layer.
Checklist
• Basic concepts:
– Computer network
– LAN/WAN/internet  Internet
– VPN, Tunneling, Intranet/Extranet
• Technical terms: e.g. UTP, Twisted Pair Lines, Ethernet, TCP, UDP, etc.
• Domain Names: describe the type of website based on the domain name.
• IEEE 802 and the protocols
• How to use DOS command the check your IP address?
• IPv4: 32 bits. Identify a valid IP address.
• Internet  future of the Internet. (slides 42)
• Institutions / Organizations
– Department of Defense / NSF / ICANN / ISO / IETF / IEEE
Exercise
• Which of the following can be an IP
address? (explain why)
– 144.37.2.3
– 144.144.144
– 144.2.3.30.40
– 144.37.2.267
Types of Networks
• LAN: (IEEE 802)
– wired: three basic topologies (pros and cons, slides
21)
– wireless: WiFi ~ IEEE802.11
(advantage of wireless)
• WAN – connecting to remote locations
– leased lines / use the publicly available networks (e.g.
telephone network, Internet), pros and cons
(page 126, figure 5-12, WAN part)
Wireless Computer Networks (radio wave)
IEEE Standard
A.K.A
Range
Speed
~30 feet
1Mbps
Bluetooth
WPAN
IEEE802.15
IEEE 802.11
11~54Mbps
Wi-Fi
WLAN
~802.11b
~ 300 ft
11Mbps
(slower)
54Mbps
(interference)
~802.11g
WMAN
IEEE 802.16
Wi-Max
~ 30 miles
75Mbps
WWAN
IEEE802.20
N/A
N/A
N/A
Computation Problems
• Speed computation
Time = Total Data Volume / Effective speed
(conversion: 1B=8 bits, 1KB = 8*1024 bits,
etc.)
• Subnet mask:
– How many computers in the subnet? 2n
– Given the number of computer, figure out n,
convert to subnet mask.
Chapter 6 Systems Development
• The concept of Systems Development
– Range of systems development, complexity compared to
program development
• Risks and challenges associated with systems
development
• System Development Methods
– SDLC
– RAD
Full name of the four methods. Characteristics of
– OOD
those methods (particularly the first two).
– XP
SDLC
• The most formal way to set up a large Information
System
• Widely adopted methods by large organizations
• 5 formal phases:
– System Definition
– Requirement Analysis  the most important phase
– Component Design
– Implementation
– System Maintenance
Describe the main activities in each phases
 What are the inputs for each phase? What are the outputs?