TDC 363
Introduction to Local Area
Networks
Winter 2008
James T. Yu, Ph.D.
jyu@cs.depaul.edu
School of CTI
DePaul University
TDC 363-01
01/03/2008
1
Today’s Class Topics
„
„
„
„
Course Goals and Overview
Introduction to LAN
Certification
The OSI Model
TDC 363-01
01/03/2008
2
Course Goals
„
„
„
01/03/2008
Theory
„
Protocols
„
Addressing Scheme
Practice
„
Network Design and Implementation
„
Lab Exercises
Certification
„
Network+
„
Others
TDC 363-01
3
1
Course Goals (cont.)
„
Understand applications of Local Area Networks (LANs)
to achieve business objectives and be able to choose
appropriate LAN technologies for particular business
applications.
„
Be able to select and interconnect LAN hardware
„
Understand LAN software implementations and design
decisions
Be able to do basic user and server configuration for
„
„
Windows 2000 services
„
Novell NetWare services
„
UNIX/Linux services
TDC 363-01
01/03/2008
4
Instructor
„
James T. Yu, Ph.D.
„
CTI (CS&T) 476
„
Phone: (312) 362
362--5938
„
Office hours:
„
Tu:: 12:30 – 01:15
Tu
„
Th:: 12:30 – 01:15
Th
„
Email: jyu@cs.depaul.edu
jyu@cs.depaul.edu
„
Web: http://facweb.cti.depaul.edu/jyu/tdc363/
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01/03/2008
5
Course Overview (cont.)
„
Class Web Site:
„
„
„
http://facweb.cti.depaul.edu/jyu/tdc363
„
Class Notes (PowerPoint Files)
„
Announcement
„
Assignments and Lab Exercises
Class notes are available 24 hours before the class
It is your responsibility to download and print a copy of
PPT/PDF slides before coming to class.
01/03/2008
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2
Course Overview (cont.)
„
Grade Components:
„
30% - Homework (3 assignments)
„
25% - Laboratory Exercises (5 exercises)
„
20% - Midterm Exam
„
25% - Final Exam
„
Total = 100
„
LAN Lab - Room 659 CTI (CS&T) building
TDC 363-01
01/03/2008
7
Grading
„
„
„
„
„
93 or higher: A
90--92: A90
A85--89: B+
85
80:84: B
75--79: B75
B-
„
„
„
„
„
70-74: C+
7065--69: C
65
60--64: C60
C50--59: D
50
Below 50: F
Class attendance will be used at the instructor’s
discretion to adjust the grade.
TDC 363-01
01/03/2008
8
Homework and Lab Exercise
„
Homework and lab exercises are submitted via the CourseCourseOn--Line (COL) web site.
On
„
„
„
„
„
Homework is due on the class time ((01:30pm
01:30pm).
).
20%
20
% late penalty for the first day ((01:30pm
01:30pm – 11:59pm)
Additional 20% penalty each day after the first day
(including weekend)
„
„
„
01/03/2008
Must be a single MS Word file
No ZIP files
I will waive the penalty for valid reasons supported by signed
documents from your doctor or your employer.
Discussion with your classmates is encouraged; however, you
must not copy each other’s work.
The school has a strict policy against plagiarism.
TDC 363-01
9
3
Exam Policy
„
„
„
„
No makemake-up exams except for valid reasons supported
by signed document from your doctor or your
employer.
You may take an exam earlier if you have a valid
reason. I will not accept personal excuse, such as
l i earlier
leaving
li for
f Spring
S i break.
b k
Exam seating is given by the instructor.
Exams are closed book, closed notes.
„
„
Calculator is allowed but no palm computer.
You are allowed to bring a 22--page (letter size) note – double
size, any font
TDC 363-01
01/03/2008
10
Chapter One
An Introduction to Networkingg
01/03/2008
TDC 363-01
11
Networks and Standalone
Computers
„
Network
„
Collection of computers connected together to
share network’s resources:
„ Network
((bandwidth))
(printer, CDCD-ROM, Tape)
„ Software (file, data, application)
„ Hardware/device
„
Standalone computer
„
01/03/2008
Uses programs and data only from its local disks
and is not connected to a network
TDC 363-01
12
4
Local Area Network
„
Evolving definitions
„
Characteristics:
01/03/2008
„
High Communications Speed (1M – 10G)
„
Very Low Error Rate (< 10-8)
„
Limited Geographic Boundaries ( <1km ???)
„
Simple Cabling System (simple encoding scheme)
„
Originally designed to use broadcast transmission to deliver
data (that is, each transmitted data packet is delivered to
all other devices on LAN).
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13
Why Network?
Answer: sharing
Sharing
g of What?
Answer: resources
What Resources?
01/03/2008
TDC 363-01
14
Single Cable Network
RJ-45 UTP Cross-over
cable
01/03/2008
TDC 363-01
15
5
LAN Type:
Peer--toPeer
to-Peer Network
„
„
Computers communicate on single segment of cable and
share each other’s data and devices
Simple example of a local area network (LAN)
01/03/2008
TDC 363-01
16
LAN Type:
Client/Server Network
01/03/2008
TDC 363-01
17
Advantages of Server
Server--Based
over Peer
Peer--toto-Peer Networks
„
„
„
„
01/03/2008
User login accounts and passwords can be
assigned in one place.
Access to multiple shared resources can be
centrally
tr ll controlled.
tr ll d
Servers are optimized to handle heavy
processing loads and dedicated to handling
requests from clients.
Servers can support a large number of
computers.
TDC 363-01
18
6
MANs and WANs
„
„
„
Campus Area Network (CAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
„
Network that spans large distance and connects
two or more LANs
„
The Internet is an example of a very intricate and
extensive WAN that spans the globe
01/03/2008
TDC 363-01
19
WAN
Connection
provided by a
Service Provider
01/03/2008
TDC 363-01
20
Public Network
Internet
Internet
Extranet
*Intranet ≠ LAN.
Intranet
Private Network
01/03/2008
TDC 363-01
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7
Network Elements
„
„
„
„
„
„
„
„
„
„
„
Workstation
Host
Client
Server
Network interface card (NIC)
Networkk Operating
i System
S
(NOS)
(
S)
Node (can be identified with an address)
Protocols – communication rules between senders and
receivers
Data Packets
Transmission Media
[Topology]
TDC 363-01
01/03/2008
22
Network Interface Card (NIC)
RJ-45
AUI
cf. Figure 1-5: A
network
t
k interface
i t f
card (NIC)
BNC
Current NIC type: PCI, USB, or PCMCIA
01/03/2008
Old days: ISA, EISA
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23
How Networks Are Used
„
Services provided by a network
„ File services (file sharing)
„ Print/Printer services (printer sharing)
„ Communications services
„ Mail services
„ Internet services
„ Management services
01/03/2008
TDC 363-01
24
8
Network Certification
„
Network+
„
Why certification?
How?
„
„
http://www.gocertify.com/certification/
TDC 363-01
01/03/2008
25
Review Questions
„
What are the advantages of network computers
vs. standalone computers?
„
What are the characteristics of LAN?
List three typical network services.
What are the advantages of clientclient-server
networking over peerpeer-toto-peer networking?
What is the difference between A+ and
Network+?
„
„
„
„
01/03/2008
Give three examples of network services
TDC 363-01
26
Chapter 2
Networkingg Standards
and the OSI Model
01/03/2008
TDC 363-01
27
9
Standards
„
Standards are documented agreements
containing technical specifications or other
precise criteria that stipulate how a particular
product
d or service
i should
h ld b
be ddesigned
i d or
performed
TDC 363-01
01/03/2008
28
Standard Organizations
„
„
„
ANSI – American National Standards Institute
EIA – Electronic Industries Alliance
IEEE – Institute of Electrical and Electronic
Engineers
„
„
„
„
„
„
Visit the IEEE standard web site
Find the document of IEEE 802.3
ISO – International Organization for Standardization
ITU – International Telecommunication Union
ICANN – Internet Corporation for Assigned Names
and Numbers
IETF – Internet Engineering Task Force
„
01/03/2008
Where can you find the standards of Internet Protocol (IP)?
TDC 363-01
29
The OSI Model
„
Open Systems Interconnection (OSI) Model
„
„
„
01/03/2008
Model for understanding and developing computercomputer-to
to-computer communication
Developed
p in the 1980s byy ISO
Divides network architecture into seven layers
TDC 363-01
30
10
The OSI Model (cont.)
01/03/2008
TDC 363-01
31
the OSI Model
01/03/2008
TDC 363-01
32
Fragmentation and Reassembly
„
„
„
Fragmentation: Divide a large data
frame/packet from the upper layer into smaller
pieces and send to the lower layer
Reassembly: Assemble smaller pieces from the
lower layer into the original frame/packet and
send to the upper layer
Fragmentation may appear at any layer of the
OSI model.
01/03/2008
TDC 363-01
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11
Flow Control
„
„
„
„
Synchronize the transmission of the sender and
receiver. In general, slows down the sender so
that the receiver can process data.
Flow control between adjacent points
Flow control between the end points.
Flow control may be applied at any layer in the
OSI model.
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01/03/2008
34
Sequencing
Sequencing:
Process of assigning a placeholder to each piece
of a data block to allowing the receiving node
reassemble data in correct order.
„ Give
Gi a scenario
i th
thatt th
the data
d t could
ld be
b received
i d
out of sequence.
„
Acknowledgement (ACK)
„
Response generated by the receiver to confirm
to the sender that the data was received
TDC 363-01
01/03/2008
35
Communications (layer1)
Application
Presentation
Session
Application
Presentation
Session
Transport
p
Transport
p
Network
Network
Data Link
Data Link
Physical
Layer-1
Device
Layer-1
Device
Physical
no addressing scheme needed
01/03/2008
TDC 363-01
36
12
Communications (layer2)
Application
Presentation
Session
Application
Presentation
Session
Transport
p
Transport
p
Network
Data Link
Physical
Network
Layer-2
Device
Layer-2
Device
Data Link
Physical
layer 2 addressing scheme needed
TDC 363-01
01/03/2008
37
Communications (layer3)
Application
Presentation
Session
Application
Presentation
Session
Transport
p
Transport
p
Network
Data Link
Network
Layer-3
Device
Layer-3
Device
Physical
Data Link
Physical
layer 2/3 addressing schemes needed
01/03/2008
TDC 363-01
38
IEEE Networking Specifications
01/03/2008
TDC 363-01
39
13
IEEE 802.3 Standard
„
„
„
„
01/03/2008
10M Ethernet – 802.3
Fast Ethernet – 802.3u
Gigabit Ethernet – 802.3z,
802 3z 802.3ab
802 3ab
10 Gigabit Ethernet – 802.3ae, 802.3an
TDC 363-01
40
Review Questions
„
„
„
„
„
Give two examples of standards from IETF
Can you find the URL of IEEE 802.11?
Give two examples of layer 2 standards specified
by IEEE.
Wh are the
What
h standards
d d for
f 10M Ethernet,
Eh
100M
Ethernet, 1G Ethernet, and 10G Ethernet?
Describe the following terms (as they are used in
the OSI model): flow control, segmentation and
reassembly, sequence control.
01/03/2008
TDC 363-01
41
Chapter 3
T
Transmissions
i i
andd
Networking Media
01/03/2008
TDC 363-01
42
14
Chapter Objectives
„
„
„
„
„
Explain data transmission concepts and digital
signals
Describe transmission cables: including coaxial
p media
cable, STP, UTP, and fiberfiber-optic
Describe different Ethernet standards
Explain the benefits and limitations of different
networking media
Identify the practices for cabling buildings and
work areas
TDC 363-01
01/03/2008
43
Media
Guided
Media
Coax
Cable
Twisted
Pair
Unguided
Media
Fiber
Optics
Infrared
TDC 363-01
01/03/2008
Radio
Frequency
44
Media Characteristics
„
„
„
„
„
01/03/2008
Throughput
Cost
Size and scalability
Connectors
Noise immunity
TDC 363-01
45
15
Coaxial Cable
„
Consists of
central copper
core
surrounded by
an insulator,
braiding,
and outer
cover called a
sheath
TDC 363-01
01/03/2008
46
Thicknet (10Base5)
„
„
„
„
Also called thickwire Ethernet
Rigid coaxial cable used on original Ethernet
networks
IEEE
EEE designates Thicknet as 10Base5
0Base5 Ethernet
Almost never used on new networks but you may
find it on older networks
„
Used to connect one data closet to another as part of
network backbone
TDC 363-01
01/03/2008
47
Thicknet Characteristics
„
Throughput
„
„
Cost
„
„
According to IEEE 802.3, Thicknet transmits data
at maximum rate of 10 Mbps
L expensive
Less
i than
h fiberfiber
fib -optic
i but
b more
expensive than some other types of coaxial cable
Connector
„
01/03/2008
Can include a few different types of connectors,
which are different from those used on modern
networks
TDC 363-01
48
16
Thicknet Characteristics
„
„
In Thicknet
networking, the
transceiver is a
separate device
and may also be
called a media
access unit
(MAU)
Attachment
Unit Interface
(AUI)
TDC 363-01
01/03/2008
49
Thicknet Characteristics
„
Noise immunity
„
„
Because of its wide diameter and excellent shielding,
it has the highest resistance to noise of any
commonlyy used types
yp of network wiringg
Size and scalability
„
Because of its high noise resistance, it allows data to
travel longer than other types of cabling
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01/03/2008
50
Thinnet (10Base2)
„
„
Also known as thin Ethernet
Characteristics:
„
Throughput
„
Cost
„
„
„
„
01/03/2008
Can transmit at maximum rate of 10 Mbps
Less expensive than Thicknet and fiberfiber-optic cable
More expensive than twistedtwisted-pair wiring
Connectors
„
Connects wire to network devices with BNC TT-connectors
„
A seen in Figure 44-19, BNC barrel connectors are used to join
two Thinnet cable segments together
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51
17
Thinnet (10Base2)
„
Characteristics (cont.):
„
Size and scalability
„
„
Allows a maximum of
185 m per network
segment
g
(see
( Figure
g 44-20)
Noise immunity
„
„
More resistant than
twisted--pair wiring
twisted
Less resistant than
twisted--pair wiring
twisted
TDC 363-01
01/03/2008
52
Thinnet (10Base2)
„
Signal bounce
„
„
„
Caused by
improper
termination on a
bus network
Travels endlesslyy
between two
ends of network
Prevents new
signals from
getting through
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01/03/2008
53
Twisted--Pair (TP) Cable
Twisted
„
„
Color--coded pairs of
Color
insulated copper wires
twisted around each other
and encased in plastic
coating
Twists in wire help
p reduce
effects of crosstalk
„
„
Alien Crosstalk
„
01/03/2008
Number of twists per meter
or foot known as twist ratio
When signals from adjacent
cables interfere with another
cable’s transmission
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54
18
Shielded Twisted
Twisted--Pair (STP)
„
STP cable consists of twisted wire pairs that are individually
insulated and surrounded by shielding made of metallic
substance
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55
Unshielded TwistedTwisted-Pair
Consists of one or
more insulated wire
pairs encased in a
plastic
l i sheath
h h
„ Does not contain
additional shielding
„
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01/03/2008
56
Unshielded TwistedTwisted-Pair
„
To manage network
cabling, it is necessary
to be familiar with
standards used on
modern networks,
particularly
„
„
„
„
01/03/2008
Category 3 (CAT3)
Category 5 (CAT5)
Category 5e
Category 6 (CAT6)
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19
UTP Cable Standards
Category
01/03/2008
Bandwidth
Use
3
16MHz
10Base
10Base--T and voice
4
20MHz
Never really used
5
100MHz
100Base
100Base--T and 1000Base1000Base-T
5e
100MHz
100BaseTX, Gigabit Ethernet
6 and 6a
250MHz
Gigabit and 10G Ethernet
7
600MHz
???
TDC 363-01
58
10BaseT
„
Popular Ethernet networking standard that replaced
10Base2 and 10Base5 technologies
A 10BaseT Ethernet network
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59
100BaseT and 1000BaseT
„
„
„
Enables LANs to run at 100100-Mbps and 1G bps
100BaseT == Fast Ethernet
Two 100BaseT specifications have competed for
popularity as organizations move to 100100-Mbps
technology:
„
„
„
„
100BaseTX: Cat
Cat--5 Cable, full duplex
100BaseT4: CatCat-3 cable, half duplex
1000BaseT: CatCat-5e cable, full duplex
10GBaseT: CatCat-6 and CatCat-6a
01/03/2008
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20
Comparing STP and UTP
„
Throughput
„
Cost
„
C
Connector
„
Noise immunity
„
Size and scalability
„
„
„
„
„
Both can transmit up to 100 Mbps
STP is more expensive
Both use RJ
RJ--45 connectors (see Figure 44--27) and data jacks
STP is more noisenoise-resistant
Maximum segment length for both is 100 meters
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61
RJ--45 Connector
RJ
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62
Different UTP Cables
„
Straight--through cable
Straight
„
Crossover cable
„
„
Terminations at both ends are identical
Terminations locations of transmit and receiver wires on one end of cable
are reversed
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21
Fiber--Optic Cable
Fiber
„
Contains one or
several glass fibers
at its core
„
Surrounding the
fibers is a layer of
glass called
cladding
A fiber-optic cable
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64
Fiber--Optic Cable
Fiber
„
Single--mode fiber
Single
„
„
Carries light pulses
along single path
Multimode
l
d ffiber
b
„
Many pulses of
light generated by
LED travel at
different angles
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65
Fiber--Optic Cable
Fiber
„
Two popular connectors used with fiberfiber-optic
cable:
„
„
„
„
01/03/2008
ST connectors
SC connectors
MT--RJ
MT
LC
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22
Fiber Types
Fiber Type Core (microns) Cladding (microns)
62.5/125
62.5
125
50/125
50
125
100/140
100
140
8.3/125
8.3
125
Advantage: noise resistance, less attenuation, and higher bandwidth.
Disadvantage: cost, installation/maintenance, and fragility.
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68
Cable Standard
for Ethernet
01/03/2008
Cable Design and Management
A structured cabling hierarchy
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23
Cable Design and Management
„
Cable plant
„
„
Hardware comprising
enterprise--wide
enterprise
cabling system
Structured cabling
„
Method for uniform,
enterprise--wide,
enterprise
multivendor cabling
systems
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Cable Design and Management
„
„
Equipment room
Telecommunicatio
ns closet
Punch-down
Punchblock
„ Patch panel is a
wall--mounted
wall
panel of data
receptors
„
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Cable Design and Management
„
Horizontal wiring
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24
Cable Design and Management
„
Work area
„
Patch cable is a
relatively short
section of twisted
twisted-pair cablingg with
p
connectors on both
ends that connect
network devices to
data outlets
01/03/2008
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74
Installing
Cable
01/03/2008
Review Questions
„
„
„
„
What is attenuation? How do you solve this problem?
Comparison of 10Base5, 10Base2, and 10BaseT: speed,
distance, cable (Coax cable, STP, UTP, and fiber),
connector (AUI, BNC, RJRJ-45).
Comparison of UTP and STP. Which one is more
popular? Why?
Various Ethernet cable standards
„
„
Data rate, cable (UTP, MM, SM), and network distance
Compare crossover cable vs. straight through cable.
Provide an example where your will use crossover
cable.
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25
Review Questions (cont.)
„
„
„
Comparison of SM and MM. Provide an
example where you will use SM and another
example where you prefer to use MM.
Draw a diagram
g
to illustrate the entrance
facility, equipment room, and telecom room
(wiring closet).
Draw a diagram to illustrate the use of punch
down block and patch panel. What are their
functions? Where do you see them?
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26