Unit 2: LAN Configurations
Lesson 2-4: Ethernet Standards
At a Glance
The lesson discusses several Ethernet and IEEE 802.3 standards.
Ethernet’s frame format and media access protocols were covered in the
previous lesson. This lesson covers Ethernet’s signaling components and
cabling. A comparison among 10BASE5, 10BASE2, 10BASE-T, 10BASE-F,
and 100BASE-T (Fast Ethernet) standards as well as media characteristics
will be covered.
What You Will Learn
After completing this lesson, you will be able to:
•
Identify the characteristics of the various IEEE 802.3 Ethernet LANs.
•
Compare and contrast the characteristics of the various IEEE 802.3
Ethernet LANs.
•
Describe the characteristics and functions of the components used in
Ethernet networks.
•
Build and troubleshoot an Ethernet network.
•
Design an Ethernet network.
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Tech Talk
•
Attachment Unit Interface (AUI)An electrical and mechanical
interface defined by the IEEE 802.3 (10 Mb/s) standard. A transceiver
cable sometimes called a drop cable, and the 15-pin connector used to
connect a NIC to an external transceiver. External transceivers are
used in 10BASE5 Ethernet networks.
•
BNC T ConnectorThe interface used to connect Ethernet 10BASE2
cable directly to the NIC and the coaxial cable.
•
Daisy chainDevices connected in series, one after the other.
Transmitted signals go to the first device, then to the second device and
on until finding the destination.
•
Fan-out unitA fan-out unit is a single transceiver that connects
multiple receivers.
•
Fiber Optic Medium Access Unit (FOMAU)A type of transceiver
used for fiber to copper connections. The two types of connections that
can be used are AUI to fiber or 10BASE-T and RJ-45 to fiber.
•
Intrusive TapA connection in 10BASE5 networks that necessitates
cutting the cable and requires that the network be shut down.
•
Media Access Unit (MAU)Point at which the data signals access
(transmit and receive) the physical media. A MAU is another name for
the external transceiver used in 10BASE5 networks. Another name for
a MAU is a vampire tap.
Media Dependent Interface (MDI)The IEEE standard for the
interface to unshielded twisted pair (UTP) cable. The connection is
established through a crossover function, which can be a crossover
cable or a port that implements the crossover function internally.
Ports that implement the crossover function internally are known as
MDI-X ports.
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•
N-ConnectorA type of media dependent interface used with thick
coaxial cable that allows a connection at the core of the cable and is
used to join two ends of thick coaxial cable.
•
Non-Intrusive TapA connection used in 10BASE5 networks that
does not require a cut into the cable.
•
Square-Connector (SC)--Ports used for fiber optic connections that
are square tabbed connectors on the end of the fiber cable.
•
Straight-Tip Port (ST)Ports used for fiber optic connections that
connect bayonet style connectors on the ends of the fiber cable.
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•
TransceiverA device that transmits and receives the data signals
for a given media. Transceivers are usually part of a NIC.
Ethernet Standards
Ethernet standards define several elements that enable transmission of
data over LANs. Ethernet refers to both the original DIX Ethernet and
IEEE’s 802.3 specifications. Data link layer protocols were discussed in
the Ethernet Basics lesson. This lesson focuses on the physical layer
protocols, comparing various Ethernet signaling devices and physical
media.
The IEEE 802.3 Ethernet CSMA/CD architecture is based on the original
DIX format established in the early 1980s by Digital, Intel, and Xerox.
Ethernet employs physical/logical bus and physical star/logical bus
topology. Current Ethernet networks use a combination of copper and
fiber optic cabling. The IEEE 802.3 cabling standards recommend the
specifications for cable types, lengths, signaling devices, and so on.
Ethernet standards change as the demands and needs of networking
change. With each change, new protocols are established.
The naming schemes for each of the Ethernet standards assist with the
identification of transmission type and cable used. For example, 10BASE5
is a 10 Mbs baseband transmission with a 500 meter distance limitation
and 100BASE-T is a 100 Mbs baseband transmission using category 5 UTP
cabling.
Ethernet 10BASE5
The 10BASE5 standard describes the original Ethernet DIX LAN. It is a
linear bus topology design where all of the computer devices are connected
together to a common shared cable. 10BASE5 transmissions are 10 Mbs
baseband as the name suggests. Recall that baseband signals use the
entire bandwidth for signaling. The “5” in the name also gives us
information about the network topology. It represents the maximum
length for each cable segment, in this case, 500 meters.
The cable type used for 10BASE5 is thick coaxial RG-8 or RG-11 with a 50
ohm resistance. Thick coaxial, also known as thicknet, is an inexpensive
cable that provides superior protection against EMI, which makes it
preferable choice for noisy environments. On the negative side, “thick
coax,” which is about the thickness of a rubber garden hose, is cumbersome
and difficult to work with and takes up a lot of space. Since thick coaxial
cannot operate at speeds higher than 10Mbs, its usefulness is limited in
higher speed networks. Because of these factors, thicknet has been phased
out of networks and is being replaced with fiber.
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IEEE 10BASE5 specifications allow for a total of five cable segments per
LAN. Therefore, 10BASE5 LANs may have a total cable length of up to
2,500 meters. Because of the extended length allowances and superior
EMI protection, thick coax was once considered the best choice for
backbone cabling. Up to four repeaters may be used to connect these cable
segments to the LAN, however, only three of the segments can have
devices. Extending the length of the LAN is the only function of the two
additional cable segments.
The five cable segment and four repeater limitations and the fact that only
three of the cable segments may be used for transceivers is referred to as
the Ethernet 5-4-3 Rule.
Each of the three cable segments that are allowed to have devices may
have up to 100 transceivers (taps) attached. Transceivers will be explained
later in this lesson. A minimum of 2.5 meters between transceivers is
recommended. Each cable segment must be terminated at both ends with
one of the ends grounded. Termination of the cable prevents signal
bounce-back.
Ethernet DIX standards allow a maximum of 1,024 computer devices per
LAN.
Minimum 2.5 Meters Between Transceivers
Minimum of Transceiver
2.5 meters
between
transceivers
Transceiver
10Base5
Cable
Attachment Unit Interface
Transceiver cable
If only three of the five cable segments can be used for transceivers and the
limit is 100 transceivers per segment, why do the standards allow up to a
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maximum of 1,024 devices? It would appear that the maximum should be
300. It is the number of transceivers that are limited to 100 per segment,
not the number of computer devices. A fan-out unit, a single transceiver
that can accommodate multiple connections, may have up to 8 devices
attached. Since this requires only one transceiver connection, the 100transceiver limitation actually allows more than 100 devices to be
connected to a cable segment. Care must be used when daisy chaining fanout units. The single transceiver is a shared device, so signal delays may
occur causing higher rates of collisions, which may slow down or
completely disable the network.
10BASE5 Components
Media Access Unit (MAU)
A media access unit (MAU), as the name implies, is the point at which the
data signals access the physical media. A MAU is another name for the
external transceiver used in 10BASE5 networks. It provides the electrical
connection and transmits signals between the Ethernet interface and
network. A MAU is a combination of a transceiver and a tap.
Taps may be either intrusive or non-intrusive. When using non-intrusive
taps, it is not necessary to cut into the cable. A non-intrusive connection is
achieved with the use of a device that clamps around the cable and inserts
a sharp metal probe through the core of the cable. An intrusive tap uses
the core of the cable as the connection point and requires cutting the cable,
which necessitates shutting down the entire network.
N-Connector
An N-connector is a type of Media Dependent Interface (MDI) connector
used with thick coaxial cable. It allows a connection at the core of the cable
and is used to join two ends of thick coaxial cable. An MDI is simply the
piece of hardware that makes the direct physical and electrical connection
to the cable. Installation of N-connectors requires an intrusive tap, cutting
directly into the cable. Special stripping and crimping tools are needed for
installation purposes and care must be taken not to damage the cable or
signal problems will result. An N-connector can also serve as a connection
point for transceivers or fan-out units (transceivers with multiple ports).
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Attachment Unit Interface (AUI) and Connector
An AUI is a transceiver cable, also called drop cable, and is used to connect
a NIC to an external transceiver. Drop cables may run a maximum of 50
meters from the transceiver (MAU) to the computer device. The AUI cable
length is not included as part of the 500 meter per segment IEEE
specification.
Transceiver, Transceiver Cable (AUI), and DIX (AUI) Connector
Transceiver
cable
Transceiver
DIX connector
AUI
An AUI connector, sometimes called a DIX connector, is a 15-pin connector
used to connect a drop cable to a NIC.
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Check Your Understanding
♦ Complete the following chart.
10BASE5
Cable type
Maximum cable segment length
Maximum number of cable segments
Maximum total cable length per LAN
Maximum number of repeaters per LAN
Maximum number of transceivers (taps) per
segment
Minimum distance between transceivers
Maximum number of segments that may have
devices
Maximum number of devices per LAN
♦ Name each of the 10BASE5 components and explain their function.
♦ What are some of the advantages and disadvantages of 10BASE5
LANs?
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Ethernet 10BASE2
10BASE2 is the IEEE 802.3 Ethernet standard proposed in 1985.
Signaling is baseband at a speed of 10 Mbs over physical/logical bus
architecture using 50-ohm thin coaxial cable. The “2” in 10BASE2
represents the approximate cable segment length, which is 185 meters.
Thin coaxial is less expensive and more flexible than thick coaxial, which
makes it easier to install. However, thin coax is more susceptible to EMI
resulting in the significantly shorter length specification. The shorter
distance limitation, however, makes it easier to troubleshoot. If distance
and EMI are not main concerns, 10BASE2 is generally the more
economical. Both thin and thick coaxial are compatible with one another
and are often used on the same network, with thin cable located in the
offices and thick cable in the ceilings and walls. When upgrades are made
to networks, it is common for 10BASE2 cabling to be replaced with the
newer 10BASET, which is explained later in this lesson.
The 5-4-3 rule also applies to 10BASE2 networks allowing up to five cable
segments, four repeaters, and three segments with devices. Use of all five
segments extends the network length to approximately 925 meters. Only
30 taps per segment are permitted under 10BASE2 specifications, with a
minimum distance between taps of 0.5 meters. Once again, the maximum
number of network devices is 1024.
10BASE2 has two versions, one uses external transceivers and can support
either single or multiple devices. The other version uses built-in
transceivers, which means that fan-out units can not be used and each
transceiver supports only one device. Fan-out units are necessary to build
a medium to large network.
10BASE2 Components
MAUs and AUIs
When an external transceiver (MAU) is used, an attachment unit interface
(AUI) and/or connector is needed to ensure that the signals can be
transmitted across the 10BASE2 cable.
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BNC Connector Connects NIC Directly to the 10BASE2 Cable
BNC T Connector 10Base2
Cable
BNC T Connector
British Naval Connectors (BNC)
Ethernet interfaces with built in transceivers can attach directly to the
cable. This is done using a BNC T Connector. One end of the T connector
connects directly to the NIC interface; the ThinNet cable is attached to the
other two T connector openings.
Check Your Understanding
♦ Complete the following chart.
10BASE2
Cable type
Maximum cable segment length
Maximum number of cable segments
Maximum total cable length per LAN
Maximum number of repeaters per LAN
Maximum number of taps per segment
Minimum distance between taps
Maximum number of devices per LAN
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♦ What are some of the advantages and disadvantages of 10BASE2
networks?
♦ Name the 10BASE2 components and explain their function.
Ethernet 10BASE-T
As networks expanded, cost became an issue and the demand for less
expensive LANs increased. The 10BASE-T standard, published in 1990,
used twisted (T) pair cable and specifications that enabled networks to use
existing telephone cabling, often already installed in buildings. Use of
twisted pair cabling reduced costs and made installation much easier.
10BASE-T uses either 100-ohm unshielded twisted pair or 150 ohm
shielded twisted pair cabling. It supports different signal speeds
depending upon the cable type. The maximum cable segment distance is
100 meters, 90 meters from the wiring closet and another 10 meters shared
between the wiring closet and office space. These smaller cable segments
are called patch cables. The maximum number of cable segments is 1,024
with up to two devices connected to each cable segment. If an Ethernet
LAN did have 1024 devices, it would not be functional because of excessive
collisions from everyone trying to access the network at the same time. In
reality the maximum number should be no more than 200 or so devices
with often as few as 5 or 10 devices.
10BASE-T is a Physical Star/Logical Bus Topology
10BaseT
cable
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10BaseT Hub
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The topology of 10BASET, while logically a bus, is physically a star. Recall
that bus topology is a cable with devices directly attached to the same
cable. The star configuration is created when devices are connected by way
of a single cable to a single point, a hub. The hub repeats the transmission
to all of the devices on the network and the devices contend for access as if
they were a bus topology. The maximum number of daisy-chained hubs is
four.
10BASE-T offers low cost, flexibility in design, ease of installation and
troubleshooting, and a choice of cable types. In addition, it can be mixed
with 10BASE5 or 10BASE2.
Unshielded Twisted Pair (UTP)
10BASE-T UTP cable is a 100 ohm cable with 4 twisted pairs, and a
maximum cable distance of 100 meters. The three UTP cable categories
are:
Category 3: Supports up to 16 Mbs
Category 4: Supports up to 20 Mbs
Category 5: Supports up to 1000 Mbs
Networks built today use category 5 cabling to ensure that a network may
be upgraded to faster speeds.
Shielded Twisted Pair (STP)
10BASE-T STP cable is a 150 ohm cable with 4 pairs and a maximum cable
distance of 100 meters. STP may be used to connect devices to hubs.
When mixing STP and UTP cabling, it may be necessary to use a
resistance matching device because of the resistance difference.
10BASE-T Connectors and Ports
The ports on hubs are configured as Media Dependent Interface with
Crossover (MDI-X) ports. The RJ-45 port on the back of a NIC is a Media
Dependent Interface MDI port. The transmit and receive connections of
the two ports are opposite of each other. The pairs used by MDI to
transmit are used to receive on an MDI-X connection and vice versa. This
twisted pair arrangement allows transmitting and receiving of signals to
take place.
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Lesson 2-4 Ethernet Standards
NIC With 8-Pin RJ-45 and BNC Coaxial Connectors
RJ-45
Connector
BNC Coaxial
Connector
There are two types of RJ-45 connectors, MDI-X RJ-45 connectors and MDI
RJ-45 connectors. You cannot connect a MDI RJ-45 connector to another
MDI RJ-45 connector; it must be connected to an MDI-X RJ-45 connector.
If the connectors are the same a special type of cable, a crossover cable is
required.
Patch cables with RJ-45 connectors at each end are used to connect the
devices to the NICs in the back of the devices and the hubs in the wiring
closet.
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Check Your Understanding
♦ Complete the following chart. When you know the chart is correct,
copy it into your portfolio for future reference.
10BASE-T
Cable type
Maximum cable segment distance
Maximum number of cable segments
Maximum number of repeaters/hubs per LAN
♦ How do UTP Ethernet resistance standards differ from STP
Ethernet standards?
♦ What speeds do the various categories of UTP cabling support?
♦ Name the 10BASE-T connectors and ports and explain their
function.
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Ethernet 10BASE-F
10BASE-F, where “F” means fiber, defines a 10 Mbs network connected
with a 62.5/125 µs multi-mode fiber optic cable. Multi-mode fiber uses an
LED signal and has a maximum distance of 2,000 meters. It has a defined
maximum attenuation of 3.75 dB/km for 850nm wavelength transmissions,
and 1.5 dB/km for 1300 wavelength transmissions.
10BASE-F Maximum Distance 2,000 Meters
Building 1
Terminator
Repeater
Building 2
2000 meters
The maximum number of devices per segment is 2, with a 1024 maximum
number of segments, each of which may have a device attached, up to a
maximum of 1024 devices. 10BASES-F topology requires a hub to receive
the signal from the network device and is therefore a physical star
topology.
In addition to allowing increased cable lengths, fiber optic cable has
several other advantages over copper cable. It is not subject to EMI,
cannot be tapped into, and no unknown devices can be added to the
network. Its extremely high bandwidths allow transmission speeds from
100 Mbs to over 2 gigabits per second. Although it is more expensive and
difficult to install than twisted pair or coax cable, it is now the preferred
cable to use as a network backbone. As the price of fiber continues to drop,
it will become more common in networks.
10BASE-F Components
Fiber Optic Medium Access Unit (FOMAU)
A transceiver must be used to connect a network interface card with a fiber
cable. There are two types of connections which may be used, AUI to fiber
or 10BASE-T RJ-45 to fiber. The transceiver is called a FOMAU for fiber
to copper connection. FOMAU provides access by converting electrical
signals to optical signals.
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Straight-tip (ST) Ports
The ports used for fiber optic connections are called straight tip or “ST”
ports. They connect to bayonet style connectors on the ends of the fiber
cable.
Square-Tip (SC) Ports
SC fiber optic connections are quickly replacing ST connectors as they are
more durable and the crossover at each end for transmit and receive is
standardized.
Each port has two connectors, one to transmit and one to receive. When a
fiber connection is made, each end must be connected in the opposite
manner. The cable ends are usually color coded red and black. If the red
connector on one end of the cable is plugged into the transmit connector,
then the red connector on the other end of the cable must be plugged into
the receive connector.
Ethernet 100BASE-T (Fast) Ethernet
100BASE-T is basically the same as 10BASE-T with two important
differences: it runs at a faster rate and it has a full duplex capacity, which
means that it can send and receive packets simultaneously. Although very
similar to 10BASE-T, several changes have increased the transmission
speed. Some of the adjustments include reducing the maximum cabling
distance to 250 meters, limiting the network to no more than two
repeaters, increasing the clock signal, and decreasing the time for
transmission of bits. To make these changes and still remain Ethernet
compatible, a sub-layer was added to the OSI MAC sub-layer.
There are three media types specified by the 100BASE-T standards. The
100BASE-T4 uses category 3, 4, or 5 STP or UTP cable, 100BASE-TX uses
category 5 STP or UTP cable, and 100BASE-FX uses duplex fiber optic
cable.
Since 10BASE-T Ethernet environments utilize category 5 cable, some
minor modifications to an existing LAN can convert it to a 100Mbs
environment. Simply replace the NICs with 10/100 base Ethernet NICs,
make sure you are using category 5 cabling, and replace the 10BASE-T
hub with a hub designed for Fast Ethernet environments.
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Lesson 2-4 Ethernet Standards
Check Your Understanding
♦ Complete the following chart.
10BASE-F
Cable type
Maximum number of devices per segment
Maximum cable segment length
Maximum number of devices per segment
Transmission speeds
♦ Describe a 100BASE-T Ethernet network.
♦ What is a FOMAU?
♦ What type of connectors are attached to the ends of fiber cable?
♦ Explain how to convert from a 10BASE-T Ethernet LAN to a
100BASE-T LAN.
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Try It Out
Determining Cabling Distances using Microscanner
In this lesson, you learned that cabling must not exceed a maximum
distance. Although your network may still function with cabling that
exceeds the maximum distance limitations, manufacturers will not honor
their warranties if you do not adhere to IEEE specifications.
Materials Needed
•
Microscanner
•
Several Patch Cables of various lengths
In this activity, you will use a microscanner to determine the length of
various cables. Your teacher will provide you with various patch cables
and/or instruct you on which areas of your network to investigate.
Directions: Obtain the microscanner and test the lengths of at least 10
different cables.
1. Insert the RJ-45 connector of the cable to be tested into the “main” port.
2. Turn the microscanner on and press the mode button until the LED
reaches the length screen.
3. The length of the cable will be displayed on the LED. Record the
information is the space provided below.
Length
WIRETRAP
FAULT
12345678
0 ft
36145278
ON
OFF
MODE
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Lesson 2-4 Ethernet Standards
Cable #1:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #2:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #3:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #4:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #5:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #6:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #7:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #8:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #9:
Length ___________ Cable Type:_______________ Cable Location __________
Cable #10:
Length ___________ Cable Type:_______________ Cable Location __________
♦ Are the cables all within the IEEE recommended distance
allowances? If not, report your findings to your teacher.
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Unit 2: LAN Configurations
Cascading Hubs into a Hub Stack
Ethernet LANs may be configured in several ways. In this lab, you will
cascade two or more Ethernet hubs using the MDI MDI-X port. Work in
groups of three or four. All the members of your team will connect their
computers to the hubs creating a Multiple Hub Ethernet LAN.
Record your actions and any problems, successes, or comments you may
have in your portfolio. In this activity you will configure a LAN using two
hubs.
The following is a review of straight through and crossover ports. Ports on
hubs that connect to network devices are called “host” ports. Host ports are
configured as Media Dependent Interface with Crossover (MDI-X) ports.
An RJ-45 port on the back of a NIC is an MDI (Media Dependent Interface)
port, meaning the wires are straight through.
When two ports transmit data, they must transmit signals over transmit
pairs and receive signals over the receive pair of wires. Transmit and
receive connections are known to be opposite to each other. Think about
talking on the telephone as transmitting and listening as receiving. The
two functions are opposites; you transmit at one end of the phone and
receive on the other. On twisted pair cable, a different pair of wires
handles each of these functions.
Twisted pair wire has 4 pairs (8 wires); with 1 pair used to transmit
signals and 1 pair used to receive signals. Refer to the cable crimping
activity diagrams in the cabling lesson for review.
Read pages 2-1 through 2-4 before beginning this activity
1. Disconnect all connectors (except power) from the hubs.
♦ Which ports on each hub are configurable to MDI or MDI-X?
♦ What is the configuration of all other ports? MDI or MDI-X
♦ Explain how you know which ports are MDI and which are MDI-X?
2. Choose a UTP cable to use to connect the two hubs together using a
connection of MDI to MDI-X.
♦ What cable did you choose? Straight through or cross-over?
3. Configure the port to be an MDI port on the first hub.
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♦ How should you configure the second hub’s port 1? Explain your
answer.
4. Using a patch cable, connect the MDI port of a hub to any MDI-X port
of another hub. If you have more than two hubs, connect them all using
the same method.
♦ When you connect the cables does the LED light go on? Yes or No.
♦ If Yes, what color is the LED? Green or amber.
♦ What does the color indicate? Refer to your portfolio for an
explanation of the hub’s port status LEDs.
5. Connect the team computers to the network of hubs. Verify that all
LEDs are green.
6. Ping all computers attached to the network. If any fail, determine the
problem and verify correction with a successful ping.
♦ How many collision domains have you created?
7. Diagram the cascading hubs.
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
Participation
20
Problems, successes, and/or comments entered in
Portfolio
20
Accurately follows directions
20
Accurate diagram of multiple hub configuration,
including labels
20
Completeness and accuracy of answers to lab
questions
20
TOTAL
222
Your Score
100
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Stretch Yourself
Troubleshooting Ethernet Multiple Hub LANs
In the previous activity, you created a multiple hub LAN configuration. In
this activity, you will refer to the hub documentation supplied by your
teacher and answer the following questions.
Materials Needed
•
BayStack 152 or 153 Hub documentation
Describe what the following Hub Status and Port LEDs indicate. Place
your answers in your portfolio for future reference.
♦ When the In is green, what does that indicate?
♦ When the Out is green, what does that indicate?
♦ When the Col is amber, what does that indicate?
♦ When the Collision/1, 5, 20 is amber, what does that indicate?
♦ When the Utilization % is green, what does that indicate?
♦ When the Link/Rx is green, what does that indicate?
♦ When the Link/Rx is blinking, what does that indicate?
♦ When the Disable is yellow, what does that indicate?
♦ When the autopartition is yellow, what does that indicate?
Answer the following questions about the rear panel ports of the
BayStack hubs. Your instructor will supply you with the
documentation that came with the hubs.
♦ Describe the Cascade In and Out ports.
♦ How many hubs can you connect in a stack?
♦ What is the maximum number of ports you can utilize?
♦ What is the Comm Port used for ?
♦ What type of connector does the Comm Port accept?
♦ What is the AUI port used for?
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Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
On time delivery of assignment
15
Questions and answers added to portfolio for
future reference.
25
Completeness and accuracy o f answers questions
60
TOTAL
224
Your Score
100
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Unit 2: LAN Configurations
Network Wizards
Proposing an Ethernet Network Design
Check with school administrators before you complete this activity. You
can propose an Ethernet LAN design according to the sample specifications
given below. However, if your school is planning on extending their
network, obtain the specifications from the school administration and use
that information to create your network design proposal.
Materials Needed
•
None
Request for Proposal
Your school wants to network a computer lab, the administration building,
and the teachers’ lounge. The number of computer lab devices to be
networked is 55: 45 workstations, and 10 printer connections. Both the
teachers’ lounge and the administration office have 5 workstations and 1
printer each. The particular specifications are listed below.
It has been decided that Ethernet will be installed. You have been hired to
submit a design proposal. The network is to be a single collision domain.
Money is a primary concern since the budget is tight. Create a single
domain network selecting the best components, cables, and configuration.
Place the correct number of devices in their proper locations on your
design. Be sure the design is fully documented, easy to read and follow.
Justify your design according to the IEEE 802.3 standards. For example
the 5-4-3 rule, numbers of devices per fan-out unit, segment, etc. Indicate
why you chose the cable types.
Work in groups of five. In addition to the design itself, a company must be
concerned with the quality and creativity of the design and presentation.
Appoint one member of the group the marketing/graphic design expert, one
or two Ethernet specialists, and one a sales/financial specialist.
The group should brainstorm the basic design and each of the team
specialists should prepare a written document covering the particulars of
his/her area of expertise. For example, the sales/financial expert should
prepare a spreadsheet of the cost of the various components.
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Meet with the group to share your findings and prepare the final
presentation to the potential clients. You will need to present your design
to the network committee in a professional manner, professionally attired,
with all the necessary documentation. Complete this assignment using all
possible resources, including your portfolio. Be prepared to answer any/all
questions the network committee participants propose. Remember, you
are “selling” both your company and your design.
Design Specifications
In the middle of the computer lab there are two rows of tables with five
tables in each row. Each table is 15 feet long and has 4 computers. Each
table is 2½ feet wide. The distance between each row of tables from front to
back is 4 feet, with 4 feet between the two rows of desks.
Along the walls of the lab are tables that run the entire length of the room
and are 21/2 feet wide. Each table contains 5 printers. The aisles between
the computer tables and the printer tables are 8 feet wide.
The teacher’s table at the front of the room has a computer and a printer
and is located six feet from the wall and four feet from the student desks.
Computer Lab
There are two electrical power receptacles beneath each of the computer
tables, four on the walls beneath the built-in side tables, and two on the
wall behind the teacher’s table.
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Administration Office
The administration building is 1,200 feet from the computer lab.
The administration building is 30 feet by 30 feet square. There are 5 offices
each 10 feet by 10 feet. The offices are placed around the perimeter of the
building. The lobby is 20 feet by 20 feet.
Each office will have a computer. The computer will be installed against
the right outside corner of each office where there are two electrical power
outlets.
The printer will be placed in the lobby, 5 feet in from office number 1
where power supply receptacle is located on the wall.
Teacher’s Lounge/Offices
The teacher’s lounge/offices are 900 feet from the computer lab and 1000
feet from the administration office. It is set up exactly like the
administration building offices.
As part of your design proposal presentation, you must include:
•
A list of equipment needed and the cost of this equipment, including all
connectors.
•
A graphical representation of your network design, which shows
cabling location and type, transceivers, repeaters, computers, printers,
and/or any other details you deem pertinent. Be sure to include
distance requirements for all cable to be installed, including AUI and
patch cables. You must adhere to IEEE 802.3 specifications.
•
A summary justifying your overall design choice. For example, if you
used repeaters, why? Why not more?
Your presentation will take place in front of the rest of the class who
represent the network committee. Be prepared to answer any questions
they pose.
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Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
Presentation skills, including ability to
accurately field questions from network
committee
25
Complete, accurate list of all necessary
equipment and the costs associated with that
equipment
25
Graphical representation showing all of the
devices, cabling specifications and accurate
cable lengths according to IEEE specifications
25
Thoughtful analysis and design choice as
indicated in the summary
25
TOTAL
Your Score
100
Summary
In this lesson, you learned to do the following:
228
•
Identify the characteristics of the various IEEE 802.3 Ethernet LANs.
•
Compare and contrast the characteristics of the various IEEE 802.3
Ethernet LANs.
•
Describe the characteristics and functions of the components used in
Ethernet networks.
•
Build and troubleshoot an Ethernet network.
•
Design an Ethernet network in response to a Request for Proposal
(RFP).
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Review Questions
Name___________________
Lesson 2-4: Ethernet Standards
Part A
1. In 10BASE5 Ethernet networks, what type of cable is specified?
a. 500-ohm thick coaxial cable
b. 50-ohm thick coaxial cable
c. 500-ohm thin coaxial cable
d. 50-ohm thin coaxial cable
2. In the 5-4-3 rule, the 5 indicates what?
a. Maximum number of taps
b. Maximum number of cable segments
c. Maximum number of repeaters
d. Maximum number of cable segments that can have transceivers
3. In 10BASE2 Ethernet networks, what type of cable is specified?
a. 500-ohm thick coaxial cable
b. 50-ohm thick coaxial cable
c. 500-ohm thin coaxial cable
d. 50-ohm thin coaxial cable
4. A straight tip connector is used with which Ethernet LAN?
a. 10BASE5
b. 10BASE2
c. 10BASE-T
d. 100BASE-T
e. 10BASE-F
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5. A BNC-T connector is used with which Ethernet type?
a. 10BASE5
b. 10BASE2
c.
10BASE_T
d. 100BASE-T
e. 10BASE-F
6. The maximum number of devices on a 10BASE-T network is what?
a. 30
b. 100
c. 500
d. 1,024
7. The maximum number of devices on a 10BASE5 network is what?
a. 30
b. 100
c. 500
d. 1,024
8. What is an AUI connector?
a. A 15-pin connector used with an external transceiver
b. Device used only with a fan-out unit
c. The standard connector used for 100BASE-T connections
d. Device used for all Ethernet connections
9. A non-intrusive network tap can cause which of the following?
a. The cable to be cut
b. Does not cause the cable to be cut
c. Causes the cable to be cut, but linked back together
d. None of the above
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10. The maximum number of devices per cable segment in 10BASE-F
networks is what?
a. 1,024
b. 500
c. 2
d. 925
11. The maximum cable length for each segment in 10BASE-T networks is
what?
a. 100 meters
b. 185 meters
c. 285 meters
d. 500 meters
12. A 10Base-T network may use which cable types?
a. Category 3
b. Category 4
c. Category 5
d. All of the above
13. The maximum number of devices per segment on a 10BASE-F network
is what?
a. 30 devices
b. 1,024 devices
c. 2 devices
d. 500 devices
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14. A fan-out unit is:
a. A single transceiver which allows multiple connections to the
network
b. The same as a repeater
c. Multiple transceivers in a box
d. Provides cooling for the network
15. What is the difference between a physical bus and a logical
bus/physical star topology?
a. The physical bus uses a hub
b. The logical bus, physical star is always used for Ethernet networks
c. The logical bus, physical star uses a hub
d. There is no difference
16. What is the topology of 10BASE-T networks?
a. Physical bus/logical star
b. Physical/logical star
c. Physical/logical bus
d. Physical star/logical bus
17. Which type of cabling is used to connect devices in a 10BASE-F
network?
a. Category 5
b. UTP
c. STP
d. Fiber optic
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18. The maximum number of repeaters/hubs per LAN allowed on a
10BASE-T segment is:
a. 4
b. 100
c. 30
d. 925
19. Maximum fiber cable distances are:
a. 550 meters
b. 250 meters
c. 2,000 feet
d. 2,000 meters
20. What is a MAU?
a. A transceiver
b. A combination transceiver and tap
c. A cable
d. A NIC
21. What is an AUI?
a. An external transceiver
b. An internal transceiver
c. A transceiver cable
d. An N-type connector
22. The 5-4-3-Ethernet rule means what?
a. No more than 5 cable segments, 4 repeaters, and 3 segments with
devices
b. No more than 5 repeaters, 4 cable segments, and 3 segments with
devices
c. No more than 5 segments with devices, 4 repeaters, and 3 cable
segments.
d. No more than 5 devices, 4 hubs, and 3 cable segments
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23. Which cable type is used in LANs over 1,000 meters in length?
a. UTS
b. STP
c. Category 5
d. Fiber Optic
24. Which type of Ethernet LAN uses a FOMAU transceiver?
a. 10BASE5
b. 10BASE2
c. 10BASE-T
d. 10BASE-F
25. Which type of copper cable is most useful when EMI and distances of
more than 1,000 meters are a concern?
a. UTP
b. STP
c. Thick coaxial
d. Thin coaxial
Part B
♦ Complete the chart below that compares and contrasts four
different Ethernet LANs.
Answer:
Characteristics
10BASE5
10BASE2
10BASE-T
10BASE-F
Cable type
Maximum cable
segment length
Maximum number
of cable segments
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Part C
♦ Name each of the 10BASE5 components and explain their function.
♦ Name the 10BASE2 components and explain their function.
♦ Name the 10BASE-T connectors and ports and explain their
function.
♦ Name the transceiver used in 10BASE-F networks and explain its
function.
♦ Describe the 10BASE-F ports.
♦ How is 100BASE-T (Fast) Ethernet different from other Ethernet
LANs?
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Scoring
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
Part A: Identify the characteristics of the
various IEEE 802.3 Ethernet LANs
40
Part B: Compare and contrast the
characteristics of the various IEEE 802.3
Ethernet LANs
25
Part C: Describe the characteristics and
functions of the components used in Ethernet
networks
35
TOTAL
100
Try It Out: Configure a LAN using two hubs.
100
Stretch Yourself: Connect Ethernet hubs and
ping.
100
Network Wizards: Propose a Network Design
to specifications.
100
Your Score
Resources
Advanced Computer Networks (1998). Networking Solutions Guide. (1998)
[Online]. Available: www.compnetworks.com/solution.htm [1999, March 1].
Aschermann, Robert (1998). MCSE Networking Essentials for Dummies.
IDG Books Worldwide, Inc. Foster City, California.
Bert, Glen (1998). MCSE Networking Essentials: Next Generation
Training Second Edition. New Riders Publishing Indianapolis, Indiana.
Casad, Joe. et al. (1997). MSCE TestPrep Networking Essentials. New
Riders Publishing, Indianapolis, Indiana.
Chellis, James; Perkins, Charles; & Strebe, Matthew (1997). MCSE
Networking Essentials Study Guide. Sybex Inc. Alameda, California.
Derfler, Jr., Frank J., & Freed, L. (1998). How Networks Work, Fourth
Edition. Macmillan Computer Publishing/Que Corporation, Indianapolis,
Indiana.
Hayden, Matt. (1998). Sam's Teach Yourself Networking in 24 Hours.
Sam's Publishing, Indianapolis, Indiana.
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HDS Network Systems, Inc. (1996). IEEE 802.3 Ethernet type. In HDS
@workStation System Administrator’s Guide [Online]. Available:
www.rzu.unizh.ch/nw/lwp/xhds/hdsdocs/netOS20/htmlsysadmin [1999, May 13].
Incorporation (1996-1999). Topics in Networking [Online]. Available:
www.uniinc.msk.ru/tech1/1994/transmis/wiring.htm [1999, March 21].
Lantronix. (1999). Ethernet Tutorial. In Technology Tutorials [Online].
Available: www.lantronix.com/technology/tutorials [1999, April 20].
Lowe, Doug. (1998). Networking for Dummies. Third Edition. IDG Books
Worldwide, Inc., Foster City, California.
Microsoft Corporation (1998). Dictionary of Computer Terms, Microsoft
Press, Redmond, Washington.
Nortel Networks (1998). Internetworking Fundamentals: Student Guide
Bay Networks Inc. Billerica, Massachusetts.
Nortel Networks (1999). NetKnowledge: Internetworking Fundamentals.
Nortel Networks, Billerica, Massachusetts.
Palmer , Michael J. (1998) Hands-On Networking Essentials with
Projects, Course Technology, Inc. Cambridge, Massachusetts.
Spurgeon, Charles E. (1997). Practical Networking With Ethernet,
International Thomson Computer Press, Boston, Massachusetts.
Spurgeon, Charles. (1993-1995). Quick Reference Guide to Ethernet
[Online]. University of Texas Office of Telecommunications. Available:
www.ots.utexas.edu/ethernet/descript-10quickref.html [1999, April 20].
The Siemon Company (1997). Siemon Guidelines to Industry Standards
[Online]. Available: www.siemon.com/horiz.html [1999, March 3].
University of Minnesota College of Education & Human Development,
Office of Information Technology. (No date). Web 66 Network Construction
Set [Online]. Available: web66.umn.edu/Construction/LAN/LAN.html [1999,
February 2].
University of New Hamphsire InterOperability Labs (1997). Tutorials and
Resources [Online]. Available: wwww.iol.unh.edu/ menu/ consortium.html
[1999, May 13].
University of Texas Pan American, Department of Computer Science
(1996). Ethernet Related Pages. In Xiannong Meng’s Home Page [Online].
Available: www.cs.panam.edu/ ~meng/ ethernet.html
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