Name: 
 

Fiber Optic Design Case Study 4



Completion
Complete each statement.
 

 1. 

This is The FOA Online Design Self-Study Program Case Study No. 4.

This exercise covers the design of a LAN Backbone. A large corporation is building a new headquarters with extensive high speed network equipment. They plan to use a fiber optic backbone for their LAN, VoIP, WiFi and other building automation and security systems.

co001-1.jpg


Basic System Information:
There is a permanently installed 24 fiber backbone cable with patchcords on either end. The total fiber/cable length is 175 meters including 170m of permanently installed cable and patchcords of 2 m on one end and 3m on the other end.

Please enter your name, CFOT/Membership number and date to begin this exercise.
 

 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 2. 

The system will be transmitting Ethernet at 10 Gb/s speeds. Multimode fiber will be used.

What will be the wavelength used for transmission?
a.
1310 nm
b.
850 nm
c.
1550 nm
d.
650 nm
 

 3. 

Which one of the following fibers are appropriate for this network?

OM1
OM2
OM3
OM4 
a.
Any of these fibers will work
b.
Either OM3 or OM4
c.
Either OM1 or OM2
d.
OM4 only
 

 4. 

If the network is planned for upgrades to 40 or  100 Gb/s over multimode fibers, the same fibers can be used but what must be included in the design plans?

a.
Better connectors
b.
Additional fibers for parallel transmission
c.
Fibers with less delay variation
d.
Lower loss in the link
 

 5. 

If the network is planned for upgrades to 40 or  100 Gb/s but will use singlemode transmission, how many fibers must be included in the design plans?

a.
2 fibers per link
b.
4 fibers per link
c.
12 fibers per link
d.
24 fibers per link
 

 6. 

The cable chosen is a distribution design to be laid in cable trays inside the office building so it must also be _____.
a.
Rated for pulling tension
b.
Rated for flame retardance
c.
Armored
d.
Water-blocked
 

 7. 

How many fibers should be in the cable?
a.
As few as possible to reduce cable size and weight
b.
As few as possible to reduce cable and splicing cost
c.
As many as possible to allow maximum flexibility and upgrades
d.
Only as many as needed
 

 8. 

In order to ensure the system will work on the cable plant being designed, it is necessary to have what information on the communication system intended for use on the cable plant?
a.
Wavelength
b.
Transmitter min/max power output
c.
Receiver min/max input powers
d.
All of the above
 
 
Typical Specifications
Provided for use as case studies for design labs in FOA courses.

Component Specifications
  
Fiber Loss 
Multimode at 850 nm3.0 dB/km (TIA 568: 3.5 dB/km)
Multimode at 1300 nm1.0 dB/km (TIA 568: 1.5 dB/km)
  
Splice Loss(TIA 568: 0.3 dB, all types)
  
Connector Loss(TIA 568: 0.75 dB, all types)
Multimode, adhesive/polish0.3 dB
Multimode, prepolish/splice0.5 dB


Active Device and System Specifications
  
Digital Transceiver Specs1Power (dBm), T=transmit, R=receive
850 VCSEL (>1 Gb/s)T:  -3 to -9 dBm, R: 0 > -18 dBm

Link margin specifications for most standardized fiber optic networks are on the FOA Tech Topics Site (http://www.thefoa.org/tech/Linkspec.htm). It should be used as a reference for designers and for the courses.
 

 9. 

Using the information supplied above, assuming the component specifications are per TIA standards, calculate the cable plant loss budget for this link.
a.
1.73 dB
b.
2.53 dB
c.
3.61 dB
d.
2.11 dB
 

 10. 

Using the information supplied above, assuming the component specifications are typical values and connectors are adhesive/polish types, calculate the cable plant loss budget for this link.
a.
1.73 dB
b.
2.53 dB
c.
3.61 dB
d.
2.11 dB
 

 11. 

Using the information supplied above, assuming the component specifications are typical and connectors are prepolished/splice types, calculate the cable plant loss budget for this link.
a.
1.73 dB
b.
2.53 dB
c.
3.61 dB
d.
2.11 dB
 

 12. 

Using the link specifications for networks from the FOA Online Reference Guide (http://www.thefoa.org/tech/Linkspec.htm) and the HIGHEST loss permitted by the TIA component specifications, which is the highest speed link that will work over the fiber?
a.
1000BASE-SX
b.
10GBASE-S
c.
4G Fibre Channel
d.
10G Fibre Channel
 

 13. 

Using the link loss budgets calculated above and specifications for networks from the FOA Online Reference Guide (http://www.thefoa.org/tech/Linkspec.htm), what are the options for making this link work with 10G Ethernet or Fibre Channel?
a.
Reduce link length but leave high loss connectors
b.
Reduce connector loss limits
c.
Choose lower loss fiber
d.
Try it anyway, there's always some "fudge factor" in standards
 

Multiple Response
Identify one or more choices that best complete the statement or answer the question.
 

 14. 

What parameters should be tested and documented to confirm proper installation?
 a.
Continuity and polarity
 b.
Insertion Loss
 c.
OTDR traces
 d.
CD and PMD
 

 15. 

Testing of each fiber in the cable should be done as follows:
(Choose all the correct answers)
 a.
Insertion loss with a light souce and power meter at 850 nm
 b.
Insertion loss with a light souce and power meter at 1300 nm
 c.
Take OTDR traces for each fiber to ensure each splice is properly made and no excess stress was used in cable installation
 d.
Continuity testing to confirm polarity when system equipment is installed
 



 
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