Unit 2: LAN Configurations
Lesson 2-5: Other Network Architectures
At a Glance
This lesson covers the basic characteristics of Token Ring, FDDI, ARCNet
and LocalTalk architecture.
What You Will Learn
After completing this lesson, you will be able to:
•
Describe the characteristics of Token Ring architecture.
•
Describe the characteristics of FDDI architecture.
•
Describe the characteristics of ARCNet architecture.
•
Describe the characteristics of LocalTalk architecture.
•
Design a Token Ring network
•
Select appropriate network architecture when given a set of
specifications.
ST0025803A
239
Lesson 2-5: Other Network Architectures
Tech Talk
240
•
Active MonitorThe computer device on a Token Ring network
whose responsibility is to ensure that the network is functioning
properly.
•
ARCNetA Token Ring network that runs over tine twisted pair RJ62/U cable at speeds of either 2.5 or 4 Mbs.
•
Beacon FrameA specialized frame, or signal, used in both Token
Ring and FDDI networks. Beacon frames are used to indicate network
malfunctions, such as a break in the ring.
•
Claim FrameA specialized frame, o r signal, used in both Token Ring
and FDDI networks that indicates that a new computer device on the
ring has been designated the active monitor.
•
Fiber Distributed Data Interface (FDDI) ArchitectureA high
speed, dual ring, token passing access network that uses fiber optic
cable.
•
Medium Interface Connector (MIC)1. An IBM designed
connector, used for Type 1 and Type 2 cabling, that may be connected to
another like connector. Two connectors are attached simply by flipping
one of them over. 2. An interface used in FDDI networks, to connect
fiber optical cable to a computer device or another fiber optical cable
segment. The MIC is also used to terminate fiber optical cable.
•
Ring WrapThe joining of the primary and secondary FDDI rings in
the event of a break in the primary ring. This process allows the
network to heal itself and continue to operate.
•
Timed Token FrameSpecialized data packet used in FDDI
networks that gives permission to a computer device to transmit data.
The rotation time around the ring is timed making it possible to
determine when a device should have token access.
•
Token FrameSpecialized data packet used in Token Ring networks
to give permission to computer devices to transmit data.
•
Token Ring ArchitectureAn IBM, IEEE 802.5 physical star,
logical ring topology technology that uses a token passing access
method for transmitting data.
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Token Ring Architecture
Token Ring architecture, introduced in the mid 80s by IBM and defined by
the IEEE 802.5 standard, is a physical star, logical ring topology. In Token
Ring networks, computer devices are connected logically in a ring with
each device connected separately to a specialized Token Ring hub called a
multistation access unit (MAU). The function of this hub is to ensure that
the packets of data are transmitted around the ring and have the ability to
bypass a device in case of failure on one of the ports. Token ring hubs have
two additional ports called Ring In and Ring Out that are used for
connecting MAUs together.
Token Ring Multistation Access Unit (MAU)
Ring In
Ring Out
Traditional Token Ring networks transmit signals at a speed of either 4 or
16 Mbs using a token that is passed from computer to computer around a
network. [Recent Token Ring technology with speeds of 100 and 128 Mbs
is called fast Token Ring networks. These networks operate like
traditional Token Ring networks]. In order to send data, a computer
device must capture the token. The token, which is continuously
transmitted around the ring, is a 24-bit frame with three fields, a Start
Delimiter (SD), an Access Control (AC), and an Ending Delimiter (ED).
Token Frame Format
SD
AC
ED
The access field carries a signal, either a 0 or 1, that tells the computer
device whether or not it is available to carry data. If available, the access
control signal is a 0, and the computer device captures the token frame,
inserts the information being transmitted in between the access field and
the ending delimiter, and then sends the entire frame.
ST0025803A
241
Lesson 2-5: Other Network Architectures
When workstation A transmits to workstation C, workstation A grabs a
free token and changes the AC to a 1 indicating that the token is no longer
available for use and encapsulates its data within the token frame
Workstation A Captures the Free Token
D
Free
Token
A
C
B
The token with its encapsulated data travels around the network from one
computer to the next, where each device accepts the frame and checks the
destination address. If the hardware addresses match, the device
processes the data; if it does not match the data is retransmitted to the
next device until the token reaches its intended destination.
242
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Data Encapsulated in Token Frame
D
A
C
Data
B
The destination device accepts the frame and copies the data, verifies
receipt, and returns the token frame to the network where it continues
around the ring until it reaches the original sending device. The sending
device recaptures the token that contains information that the frame was
received and also contains error control information. After stripping the
original data from the frame, the sending device returns the available
token to the network and the process continues.
ST0025803A
243
Lesson 2-5: Other Network Architectures
Workstation C Accepts Data and Sends it Back to A to be Stripped
D
Data
Data
A
Free
Token
C
Data
B
Four (4) Mbs Token Rings only allow one token on the ring at a time,
sixteen (16) Mbs Token Rings have a mechanism called Early Token
Release, which allows a free token to be released before it has been
completely received by the source station.
Token Ring networks are not as susceptible to signal degradation as other
network types, since each device acts like a repeater, regenerating the
signal before transmitting it to the next device. Token Ring networks fail
more gracefully than Ethernet networks when they are overloaded. Since
they are so reliable, diagnostic and troubleshooting measures are often
built into the hardware. Also, priority can be assigned in Token Ring
networks.
Although they work quite well, Token Ring networks are currently being
phased out for several reasons. They have very complicated protocols,
which makes them both difficult to troubleshoot and more expensive than
other technology. Token Ring is basically IBM, so there are compatibility
issues with equipment from other manufacturers who also are not as
interested in new Token Ring technology since the market isn’t as
profitable as the Ethernet market. Additionally, 4 Mbs networks are
considered slow when compared with 10Mbps Ethernet networks.
244
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Token Ring Frame Format
Token Ring frame format begins with the 8 bit Start Delimiter followed by
the 8 bit Access Control. The next field, is a Frame Control field, which
indicates whether the frame contains Media Access Control information for
all network devices or only data for a single destination device. This field
is followed by the Destination Address field (either 16 or 48 bits), the
Source Address field (either 16 or 48 bits), the Data field (has no
determined size), the Frame Check Sequence field (32 bits), the End
Delimiter field (8 bits), and finally the 8 bit Frame Status field. [Note:
current Ethernet LANs use the 48bit source and destination addressing
scheme.]
Token Ring Frame Format
8
8
bits bits
SD
AC
8
bits
16 or 48
bits
16 or 48
bits
Frame Destination Source
Control
Address
Address
>0
bits
Data
Field
32
bits
FCS
8
bits
ED
Detecting Errors through Beaconing
One computer device on a Token Ring network, usually the first device
recognized when the LAN comes up, is designated the active monitor. It is
the responsibility of the active monitor (AM) to ensure that the network is
functioning properly. Every seven seconds the active monitor (AM) station
sends a signal/frame, which checks for malfunctioning devices and
problems such as errors in delivery of frames. Each successive device on
the ring receives and forwards the active monitor present frame. If a
device does not receive the active monitor (AM) present frame, it sends a
message/frame on to the network indicating that there is a malfunction,
and the Token Ring tries to self-correct the problem. If the active monitor
(AM) malfunctions, its nearest active upstream neighbor (NAUN) becomes
the new active monitor (AM) and sends out a Claim Token notifying all
other devices of the change in active monitor status.
ST0025803A
245
Lesson 2-5: Other Network Architectures
Token Ring Components
Cabling
The specified cable in the IEEE 802.5 Token Ring standard is 150 ohm
STP. IBM Token Ring networks use UTP, STP, and fiber optic cable types.
The chart below indicates the IBM cable types, their description, and
common uses.
IBM Cable Type
Description
Type 1
Two-pair 22 AWG STP wire used for conduits
and outside walls
Type 2
Two-pair 22 AWG STP wire for data and fourpair 26 AWG wire, outside the shield, used for
telephone (voice). Commonly used for trunk
cable.
Type 3
Four-pair 22 or 24 AWG UTP wire, which
requires a media filter for use in Token Ring
networks. Susceptible to EMI since it is
unshielded wire. Also can’t be used for 16 Mbs
Token Ring networks.
Type 5
100/140 micron two strand fiber optic cable,
which is used for the main ring of Token Ring
networks.
Type 6
26 AWG flexible STP wire used for patch or
extension cables.
Type 8
Single copper core 26 AWG STP specifically
designed for use under carpets.
Type 9
Single pair Plenum grade 26 AWG STP fire
resistant wire. Used in walls and ceilings.
Token Ring Network Interface Adapter Cards
Token Ring Network Adapter Cards, specialized interfaces used to connect
devices on Token Ring networks are available for both 4 Mbs and 16 Mbs
Token Ring networks. A 16 Mbs Token Ring NIC can be used on a 4 Mbs
network; however a 16 Mbs network must use 16 Mbs adapter cards.
246
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Multistation Access Units
Multistation Access Units (SMAU), are specialized hubs (sometimes called
concentrators) made specifically for Token Ring networks. These hubs
have an internal wiring arrangement that allows the computers to be
connected in a continuous ring. MAUs have the ability to bypass failed
computer devices connected to the ring. One way a MAU knows that a
device has failed is through a specialized signal that goes by the nickname
Heartbeat. It is a small signal sent by the MAU to the NIC every once in a
while to tell the NIC that it is still connected. Heartbeat is also used by
10BaseT NICs to tell the hub that they are still connected. Some hubs will
automatically disconnect a port if there is no heartbeat signal present to
keep the port alive. Typical MAUs connect eight or more computer devices
and, according to standards, up to 12 MAUs can be interconnected.
Adapter and Patch Cables
A Token Ring adapter cable typically has a nine-pin connector at one end
that attaches to the back of the NIC and a special IBM data connector that
connects to the MAU at the other end. Adapter cables may also have
telephone-jack-type cable connectors.
Patch cables are Type 6 IBM cables that come in standard lengths of 8, 30,
75, or 150 feet. They are used to extend the distance of a computer device
from the MAU, or to attach two MAUs.
Media Filters
A media filter is used to connect a Token Ring adapter card to an RJ-11 or
RJ-45 wall jack. A media filter is required when Type 3 telephone cable is
used or when a NIC card with a DB-9 interface is connected to the hub.
The media filter converts different signals and reduces noise interference.
Connectors
Many different types of connectors are supported within a Token Ring
network. The type of connector specifies the type of cabling that is
acceptable. If UTP cabling is used, both the cable and connectors must
have the same category rating.
Token Ring connectors include the following:
•
DB-9 ConnectorUsed for STP cable. May be used for a trunk
connection or device connection. Most commonly found on the back of a
Token Ring NIC card. A DB-9 must have a media filter attached if used
with UTP cable.
ST0025803A
247
Lesson 2-5: Other Network Architectures
DB-9 and IBM Data Connector
DB-9 Connector
NIC
STP Cable
IBM Data Connector
STP Type 1 and UTP Category 5 copper cable may be used for the ring
device connections.
IBM Data Connector
248
•
RJ-45An 8-pin standard telephone-jack-type connection used to
connect UTP or STP cables.
•
RJ-11A 4-pin telephone-jack connector used for Type 3 cable
connections.
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
•
Straight Tip (ST)Connector used with fiber cable . Two connectors
are required per port, one transmits and one receives.
Straight Tip Connector
Check Your Understanding
♦ What are the advantages of a Token Ring Network?
♦ What is a token?
♦ What is a MAU?
ST0025803A
249
Lesson 2-5: Other Network Architectures
Fiber Distributed Data Interface (FDDI)
Fiber Distributed Data Interface (FDDI) is a high speed (100 Mbs), fiber
optic LAN technology that uses the token passing method to access the
network. The American National Standards Institute (ANSI) developed
standards for FDDI networks (X3T9.5) that address the Physical and
Media Access Control sub-layers of the OSI model. It assumes the use of
IEEE 802.2 Logical Link Control sublayer standard above the MAC sublayer. FDDI uses physical star, logical ring topology. FDDI is a dual ring
topology that is commonly used between LANs in metropolitan area
networks to provide high speed connections.
Like Token Ring, FDDI uses a token frame to pass data from one station to
the next around a ring until it returns to the source device; however, an
additional clocking field is added to the beginning of the token. This field
is added because FDDI transmissions are synchronous and require a
clocking mechanism. Voice and video transmissions are examples of data
that require synchronization.
When a free token is available, a computer device is allowed to transmit its
data. Unlike Token Ring, which can transmit only one frame at a time,
with FDDI the computer device can transmit as many frames as possible
until a predefined time limit is reached. When the device either has no
more frames to send or the time limit is reached, it stops transmitting data
and immediately releases an available token. In Token Ring, the free
token was not released until after the sending device received the frame it
sent indicating receipt and/or errors.
Because the token is transmitted as soon as a computer device is finished
transmitting frames, it is possible for a device on the ring to transmit new
frames while other frames are still circulating around the ring. It is
therefore possible for multiple frames from multiple devices to be on the
network simultaneously.
FDDI networks are commonly used to connect LANs where either EMI or
distance are problems. Computer devices can be as far apart as 2
kilometers and FDDI networks can support up to 1000 devices per LAN.
250
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
FDDI Rings
FDDI Dual Rings
Primary ring
Secondary ring
The dual rings are classified as primary or secondary. Devices on FDDI
networks may be connected to both primary and secondary rings or only
the primary ring. If there is a malfunction on the primary ring, the
secondary ring automatically wraps to the first ring forming a complete
ring once again. This is referred to as “ring wrap” and is an automatic
function of FDDI. A type of claim token frame is used in FDDI networks
to detect errors in transmission or timing.
A device connected to both the primary and secondary rings is classified as
a dual-attached station or Class A station. A single-attached or Class B
station, is attached to only the primary ring. Typically, a Class A station
would be a hub and a Class B, a computer workstation. The Class B device
would connect to the primary ring and through that connect to the hub.
ST0025803A
251
Lesson 2-5: Other Network Architectures
FDDI Frame Format
In addition to the four token fields FDDI networks include the following
fields as shown in the diagram below:
FDDI Frame Format
LLC-PDU
SSAP
DSAP
Frame Information
Address Address Control
MAC Frame
Starting
Preamble Frame
Delimiter
8 octets
252
1 octet
Frame
Control
1 octet
Dest.
Source.
Frame
End
MAC
MAC Information Check
Frame
Address Address
Sequence Delimiter
2 or 6
octets
2 or 6
octets
0-4478
octets
4 octets
Frame
Status
.5 octet 1.5 octets
•
Preamble: this field, which consists of all 1s, is used as a clocking
mechanism and indicates the beginning of a frame.
•
Start Delimiter: designates the physical start of the FDDI frame.
•
Frame control: indicates the length of the address and the transmission
type (synchronous/asynchronous and data/network information).
•
Destination Address field.
•
Source Address field.
•
Data: application and upper layer protocol data.
•
CRC: error checking frame.
•
End Delimiter: signifies the end of the data frame.
•
Frame Status field: offers further error checking.
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
FDDI Media
Cabling
Fiber optic cable is specified as the standard for FDDI and may be single or
multi-mode fiber. Single mode fiber optic cable uses laser technology and
can transmit up to a maximum of 20 km without using repeaters. Multimode fiber is less expensive. Instead of laser technology, it employs LED,
light emitting diode technology, and can transmit signals of to a maximum
distance of 2 km.
Dual Attachment Concentrator (DAC)
A dual attachment concentrator is a hub used in FDDI networks that are
capable of attaching to dual counter rotating rings. DACs have additional
ports, called trunk ports, used to connect to additional concentrators or
other FDDI computer devices.
FDDI Network Adapter Cards
The transceiver in FDDI networks is built into the FDDI NIC. It is a laser
transceiver used to convert digital data to light impulses and vice versa.
FDDI Connectors
The connectors used in FDDI networks are Media Interface Connectors
(MIC).
There are several types of MICs. They are typically color coded to assist in
allowing only desirable port connections. During installation and
troubleshooting when cable connections are often moved, it is important to
keep the color-coded key attached to the MIC connector.
Check Your Understanding
♦ What are differences between FDDI and Token Ring networks?
ST0025803A
253
Lesson 2-5: Other Network Architectures
LocalTalk
Since its introduction in 1984, Apple Computer has included a built-in
network interface on every Macintosh. LocalTalk is a low-speed network
that was designed to work in small workgroups with a few devices. The
network transmits data at 230 kilobits per second, about 40 times slower
than the slowest Ethernet network. Although much slower that Ethernet,
LocalTalk is about four times faster than 56Kbps modems, which makes it
viable for small offices with 5 – 10 users.
In contrast to Ethernet use of CSMA/CD, LocalTalk uses the CSMA/CA
access method. The CA (carrier avoidance) portion sends a signal on the
wire to reserve the line for use. All other stations back off for a
predetermined amount of time until the line is free again.
LocalTalk
Connector
module
8-pin plug
LocalTalk
cable
The original version of LocalTalk from Apple used a shielded 2-wire cable
to transmit data. The system used a bus topology in a fashion similar to
10BASE2. Although LocalTalk is easy to install and use, it is very slow and
does not support more than 253 devices and is limited to a maximum of 32
devices per daisy chain.
LocalTalk Addressing
LocalTalk provides three levels of addressing: node, network, and socket.
Node ID
You'll remember that one of the requirements of a data link layer protocol
is to move data from device-to-device on a single LAN. To do so, each device
on the network requires a unique address. On Ethernet and Token Ring
network interface cards, this address is located in some form of nonvolatile memory. For the Macintosh, Apple chose a different approach.
Instead of storing a unique network address into every Macintosh
254
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
computer, an address is dynamically assigned each time the computer is
turned on. Apple calls this address a Node ID.
The Node ID is a Data Link layer address that uniquely identifies each
device on a single network. The Node ID is 8 bits and ranges from 0 to 255.
Node IDs 0, 254, and 255 are reserved resulting in a possible 253 addresses
per network.
Network ID
The Network ID is a Network layer address that uniquely identifies each
network on an internetwork. The Network ID is 16 bits and ranges from 0
to 65,535. This allows a maximum of 65,536 networks each with 253
devices for a total of 16,580,608 devices.
DIN type connectors for STP cabling and LocalTalk can now use UTP with
RJ-45 connectors.
The Datagram Delivery Protocol (DDP) is LocalTalk's Network layer
protocol. DDP provides connectionless, best-effort data delivery and
provides no acknowledgement sent to the receiver.
Check Your Understanding
♦ Compare the speed of LocalTalk with Ethernet:
♦ How is LocalTalk addressing different from Ethernet and Token
Ring?
ARCNet
Attached Resource Computer network was developed in the late 70s for
small LANs as a token passing media access control network topology that
transmits data at speeds 2.5 Mbs. Tokens in ARCNet networks are passed
according the MAC address rather than in succession from one computer to
the next computer device. ARCNet is fast becoming obsolete and many
vendors no longer sell this technology, though it is sometimes still found in
some small offices.
Topology is either bus, star, or a combination. If bus topology is used, the
maximum distance per segment is 305 meters. With the addition of an
active hub that repeats the signals, the maximum distance between the
computer device and the hub is 610 meters when using BNC connectors
and coaxial cable and 244 meters when using twisted pair and RJ-11 or
RJ-45 connectors.
ST0025803A
255
Lesson 2-5: Other Network Architectures
ARCNet Media
ARCNet networks use coaxial, UTP, STP, and fiber optic cable although
the standard cable is 93-ohm, RG-62A/U coaxial.
Hybrid Architectures
Incorporating more than one type of architecture when connecting and
expanding LANs is not uncommon. A specialized bridge, called a
translational bridge, must be used when interconnecting LANs using
different data link layer protocols and different physical network media
(for example, Token Ring to FDDI). It must be able to convert the frame
format of one media type into the frame format of another media type.
Translating Bridge
FDDI
T r a n s la t io n a l B r id g e
Token
R in g
256
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Try It Out
Ethernet or Token Ring?
Materials Needed
•
None
Write a one-page scenario about a fictitious company that is trying to
decide whether it should use an Ethernet or IBM Token Ring network?
Your scenario should include the following information:
•
Type of company
•
Number of employees
•
Network access requirements
•
Network reliability needs
•
Physical layout requirements
•
Type of equipment
•
Type and amount of data to be transmitted
Should this company use an Ethernet or IBM Token Ring network? Write
a one page analysis of your choice. Include in your analysis your reasons
for the choice. Defend as many aspects of your choice as possible.
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
On time delivery of assignment
10
Quality of product, including spelling, grammar,
and overall appearance
20
Complete scenario
25
Thorough and accurate analysis and defense of
network choice
45
TOTAL
Your Score
100
ST0025803A
257
Lesson 2-5: Other Network Architectures
Stretch Yourself
Token Ring/FDDI Project
Materials Needed
•
None
Use your imagination and develop your own Token Ring or FDDI project.
Interview an information specialist whose company uses a Token Ring or
FDDI network and write a summary of your interview; write a research
paper; create lyrics for a hip-hop, rap, blues, or hard rock Token Ring song;
create a Token Ring or FDDI poster; build a diorama or produce a video
about Token Ring networks; create a Token Ring FAQ web page; develop a
power point Token Ring presentation; prepare a marketing presentation
for Token Ring or FDDI networks; or, use your own idea.
Make arrangements with your teacher for approval of your project and for
your specific requirements. This may be either a group or an individual’s
project. Agree upon a due date. Agree upon the final product.
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
On time delivery of assignment
10
Overall appearance/presentation of final product
20
Originality and creativity
20
Accuracy of Token Ring network technical
information
20
Other (teacher/student criteria for chosen project)
30
TOTAL
258
Your Score
100
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Network Wizards
Token Ring Case Study
Materials Needed
•
None
In this case study, you will have the opportunity to design a Token Ring
network that meets certain specifications.
The second largest video company, Blue Mood Video, is installing their
first network. They have decided to install Token Ring to network their
point of sale terminals for their large store. They have not decided if they
need 4 or 16 Mbs.
There are 5 sales terminals, 2 servers, and 2 printers. They want to
connect to the Internet. STP cable was left installed by the last occupant.
You have been hired to recommend the network speed and to design the
network. Prepare a summary that addresses all of the network
specifications and design questions. Include a one-page summary of the
reasons for your choice and a diagram of the proposed network. Add this
information to your portfolio.
Network Specifications
•
The sales terminals need to respond quickly to handle the high volume
of sales.
•
They would like to use the currently installed cable, but are not sure if
it will meet their needs.
•
The network needs to last and not need to be replaced in the near
future.
•
Add the servers and printers to appropriate locations within the store.
•
List all of the necessary equipment.
•
Create a diagram to show your network and all of the devices. Label
devices and give them MAC addresses
ST0025803A
259
Lesson 2-5: Other Network Architectures
Design Questions
♦ What transmission speed did you choose?
♦ Why did you choose the ring speed?
♦ Why?
♦ What cable type did you choose?
♦ Why?
♦ What type of connector(s) did you choose to use?
♦ Why?
♦ What device did you choose to use in the center of the network?
♦ Why?
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
On time delivery of assignment
10
Accurately addressed all network specifications.
15
Accurately addressed all design questions
15
Information placed in portfolio
10
One-page summary
20
Diagram of network
20
List of necessary equipment
10
TOTAL
260
Your Score
100
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Summary
In this unit, you learned the following:
•
Describe the characteristics of Token Ring architecture.
•
Describe the characteristics of FDDI architecture.
•
Describe the characteristics of ARCNet architecture.
•
Describe the characteristics of LocalTalk architecture.
•
Design a Token Ring network to specifications.
•
Select appropriate network architecture when given a set of
specifications.
ST0025803A
261
Lesson 2-5: Other Network Architectures
Review Questions
Name_______________________
Lesson 2-5: Other Networking Architectures
Part A
1. Token Ring networks operate at
a. 10, 100 or 1000 Mbps
b. 4, 16, 100 or 128 Mbps
c. 1 Gbps
d. 10, 16 or 1000 Mbps
e. 4 or 10 Mbps
2. A device may use the token frame to send data if
a. The Start Delimiter is 0
b. The End Delimiter is 1
c. The hardware addresses match
d. The Access Control signal is 0
e. The Start Delimiter is 1
3. The Token Ring token frame size is
a. 16 bits
b. 24 bits
c. 32 bits
d. 48 bits
e. 64 bits
262
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
4. After copying data from the token frame, a receiving device
a. Releases the token
b. Reads error control information from the frame
c. Uses the token frame to send new data
d. Destroys the token frame
e. Send the frame back to the sending device
5. Token Ring networks
a. Fail more often than Ethernet networks
b. Fail more gracefully than Ethernet networks
c. Never fail
d. Cannot accept priority assignments
e. Must use fiber optic cabling
6. To detect and correct errors
a. Every device on a Token Ring network is an active monitor
b. Each device on a Token Ring network diagnoses its own errors
c. Each device gives control to its nearest active upstream neighbor
d. One device is designated as the active monitor
e. All devices send out a Claim Token
7. A MAU
a. Connects Token Ring devices into a ring
b. Turn off the ring when any connected device fails
c. Route power to connected devices
d. Switch traffic to neighboring networks
e. Cannot connect to other MAUs
ST0025803A
263
Lesson 2-5: Other Network Architectures
Part B
1. FDDI operates at
a. 10 Mbps
b. 4 or 16 Mbps
c. 100 Mbps
d. 1000 Mbps
e. 4.5 Mbps
2. To transport streaming media data, FDDI
a. Opens a switched circuit
b. Can synchronize data with a clocking field
c. Can only transmit one frame when the token has been captured
d. Uses fiber optic cabling
3. When an FDDI sending device has captured a token
a. It can only transmit one frame
b. It can transmit as many frames as it wants
c. It can only transmit error diagnostics
d. It can transmit frames until a time limit expires
e. It releases the token
4. A secondary ring in FDDI
a. Automatically steps in if the primary ring fails
b. Allows priority communication to select devices
c. Doubles communication speed
d. Connects to Token Ring networks
264
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Part C
1. Which computer manufacturer uses LocalTalk?
a. IBM
b. Digital Equipment Corporation
c. Intel Corporation
d. Motorola
e. Apple Computer
2. LocalTalk operates at
a. 230 Kbps
b. 1 Mbps
c. 10 Mbps
d. 100 Mbps
e. 1 Gbps
3. LocalTalk Node Id’s are assigned
a. By the manufacturer
b. By the user
c. By the computer when the device is powered up
d. By the computer when the device is installed
e. By the server
4. LocalTalk connects using
a. Fiber optic cable
b. Coaxial cable
c. Twisted pair cable
d. Microwave radio
e. Photonic switches
ST0025803A
265
Lesson 2-5: Other Network Architectures
Part D
1. ARCNet operates at
a. 230 Kbps
b. 1 Mbps
c. 2.5 Mbps
d. 10 Mbps
e. 1 Gbps
2. ARCNet tokens are passed by
a. nearest active upstream neighbor
b. nearest active downstream neighbor
c. Random walk
d. MAC address
e. NAUN computer device
3. ARCNet connects using
a. Twisted pair or coaxial cable
b. Fiber optic cable
c. Infrared light
d. Microwave radio
266
ST0025803A
Internetworking Fundamentals
Unit 2: LAN Configurations
Scoring
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
Part A: Describe the characteristics of Token
Ring architecture.
25
Part B: Describe the characteristics of FDDI
architecture.
25
Part C: Describe the characteristics of
ARCNet architecture.
25
Part D Describe the characteristics of
LocalTalk architecture.
25
TOTAL
100
Try It Out: Select an appropriate network
architecture when given a set of
specifications.
100
Stretch Yourself: Characteristics of either
Token Ring, FDDI, or other architecture
100
Network Wizards: Design a Token Ring
network to specifications.
100
FINAL TOTAL
400
Your Score
Resources
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.
Carol, J. T. & Love, R.D. (1995). Dedicated Token Ring. In The Token
Ring Consortium Report [Online]. University of New Hamphsire
InterOperability Labs. Available:
www.iol.unh.edu/consortiums/tokenring/MACs_n_PHYs/Fall95/Special_Feature.ht
ml. [1999, April 30].
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.
ST0025803A
267
Lesson 2-5: Other Network Architectures
CMP Media, Inc. (1999). FDDI fundamentals. In Data Communications
Tech Tutorials [Online]. Available:
www.data.com/Tutorials/FDDI_Fundamentals [1999, April 20].
Computing and Communications Services Office, University of Illinois at
Urbana-Champaign (1999). Network Administrator’s Survival Handbook.
Available: www.ntx2.cso.uiuc.edu/nas/network_adminstrator.htm [1999, May
13].
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.
Lantronix. (1999). Ethernet Tutorial. In Technology Tutorials [Online].
Available: www.lantronix.com/technology/tutorials [1999, April 20].
Lindsay, S., Rosenblum, D. & Walleigh, W. (1998). Token Ring Switching.
In Technology [Online]. 3Com Corporation. Available:
www.3com.com/nsc/500603.ntml [1999, April 30].
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.
268
ST0025803A
Internetworking Fundamentals