Transcript Ch 5 Network Communication

Introduction to Management Information Systems
Chapter 5 Data Communications
and Internet Technology
HTM 304
Fall 07
Content
1. 5-layer Architecture for Communication
2. Internet
3. Enterprise Network
4. Wireless
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Last Time: The 5-Layer Model
Hardware Layer: Set the devices
ready for communication.
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Layer 3: Internet Layer
Runs the IP protocol
Data received from the above layers are divided into packets.
Key design issue – to determine how packets are routed from source to
destination.
Routing: selecting paths – shorter route, avoiding heavy traffic, etc.
Router: special-purpose computing devices that process IP protocol –
examine the destination IP addresses and decide where to send them.
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IP Address (IPv4)
Layer 3 handles IP address.
The Logical Addresses
Assigned when you get
online, not permanently tied
with the MAC address
Why? Don’t have to update
every time a NIC is
changed
An IP address is four bytes,
totally 32 bits.
How many in total?
You can either specify your
IP address (as most of the
company’s server), or let the
ISP assign one dynamically.
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IPv6
Windows Vista has adopted IPv6.
Totally 128 bits (=16 bytes) instead of 32 bits (=4 bytes)
How many total IPv6 addresses? 2128  3.4 * 1038 addresses
Approximately 5 * 1028 addresses * 6.5 billion people alive today.
Example of address: (8 Hexadecimal digits)
2001:0db8:85a3:08d3:1319:8a2e:0370:7334
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Exercise: Find your IP address
How to find your IP address?
“start”  “run”: type “cmd” and click ok, the command prompt
window will pop up
Type command “ipconfig” to observe the report
Use “ping” command to check the connectivity between two
computers
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Router – 3rd Layer Equipment
Computer A
Packets:
Original IP – source IP + Data
Computer B
Application
Layer
Frames:
Original MAC – Next MAC + Packets
Application
Layer
Transport
Layer
Router A
(can actually many)
Transport
Layer
Internet
Layer
Internet
Layer
Internet
Layer
Data Link
Layer
Physical
Layer
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Data Link
Data Link
Layer
Physical
Layer
Data Link
Data Link
Layer
Physical
Layer
Explain: Why Router? – handle address
Can be substituted by
a computer with routing
Programs installed.
Multiple NICs needed.
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Layer 4 Transport Layer
Handles transport protocol: TCP or UDP – software protocols
Application
Layer
Transport
Layer
Once paths from computer A to B
is found, an end-to-end connection
is established on the 4th layer.
Meaning data can be transferred.
Application
Layer
Internet
Layer
Internet
Layer
Internet
Layer
Data Link
Layer
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Data Link
Point-to-point
Data Link
Layer
Data Link
Transport
Layer
Data Link
Layer
Physical
Layer
Physical
Layer
Physical
Layer
Computer A
Router A
(can actually many)
Computer B
Layer 4 Protocols
TCP: Transmission Control Protocol
Receive data and transmission request from Layer 5 (application layer)
Send communication request to layer 3, layer 3 will then find one or
more route to the destination computer.
Destination computer send acknowledge back, indicating there is end-toend connection.
Break data from layer 5 into segments, and send each segments with
confirmation. (destination computer send acknowledge upon receiving
every segment)
UDP: User Datagram Protocol
Designed for short messages
Does almost everything the same as the TCP, except not requesting
confirmation.
Faster, more efficient for short messages and time-sensitive application
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Layer 5 The Application Layer
Layer 5 protocols for applications such as browsers, email, file
transfer, etc.
A standard email protocol
Simple Mail Transfer (SMTP)
Web page processing
Hypertext Transfer Protocol (HTTP)
File Transfer Protocol (FTP)
It governs how applications work with each other. (e.g. Firefox
v.s. IE 7)
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Review of the 5 layers
See your handout
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Review the Data Process
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Exercise
Which of the following is referred to as
the network cable?
Coaxial Cable
Fiber Optic Cable
Unshielded Twisted Pair
Twisted Pair Copper
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More exercise?
What is the name of data unit
transferred on the 2nd layer?
Packet
Bytes
Package
Frame
Segment
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Explain IEEE 802?
Which of the following standard in IEEE 802 is referred to
as Ethernet?
IEEE 802.11
IEEE 802.15
IEEE 802.3
IEEE 802.5
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Describe the three topologies mainly used to connect a
LAN. Describe the pros and cons.
Which one can be extended to a large geographic area
Which topology corresponds to the Ethernet?
Describe the difference between an “end-to-end”
connection and a “point-to-point” connection?
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Multiple Choices
__________ contains the destination computer’s IP
address in its header.
A frame
A segment
A packet
An email message
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