Name: 
 

Fiber Optic Design Case Study 7 - Data Center



Completion
Complete each statement.
 

 1. 

This is The FOA Online Design Self-Study Program Case Study No. 7, Data Center.

This exercise covers the design of a  A Data Center. A data center is being built to expand a corporate network and support Internet servers for a large audience. Connections are planned to use 10G Ethernet but upgrades to 40 or 100 GbE are expected in the future. Besides providing adequate capacity, reducing energy consumption is important, leading to a choice of fiber over copper for its lower power requirements. 

co001-1.jpg
The servers will be using a "top of rack" design. Cabling is planned to  be installed in underfloor wire tray, however, alternatives may be considered. The permanently installed cables will be terminated in patch panels and short patchcords used to connect the servers.



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 servers will be in a "top of rack" design configuration. What kinds of cables are appropriate for use in the short 10G Ethernet connections of the switch to the servers in the rack?
a.
UTP Cat 6A
b.
MM fiber, OM3/4
c.
Coax CX-4
d.
Any of these
 

 3. 

The system will be transmitting Ethernet at 10 Gb/s speeds over relatively short lengths of multimode fiber between switches.
What will be the wavelength used for transmission?
a.
1310 nm
b.
850 nm
c.
1550 nm
d.
650 nm
 

 4. 

What is the minimum performance grade of  multimode fibers appropriate for this installation, assuming links are more than 100m?

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

 5. 

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

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

 6. 

If the network is planned for upgrades to 40 Gb/s using the same multimode fibers, how many fibers must be included in the design plans?

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

 7. 

If the network is planned for upgrades to 100 Gb/s using the same multimode fibers, 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
 

 8. 

If the network is planned for upgrades to 40 or  100 Gb/s but will use multimode transmission with VCSELs using wavelength-division multiplexing, 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
 

 9. 

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
 

 10. 

The cable chosen for inside the buildings 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
 

 11. 

The equipment for 10 GbE generally uses ___ connectors so it may be more convenient to use them in the cable plant also.
a.
ST
b.
SC
c.
LC
d.
MTP/MTO
 

 12. 

If a prefab cable plant with preterminated cables is used, the backbone cables will propably use ________ connectors with parallel fiber connections.
a.
ST
b.
LC
c.
SC
d.
MTP/MPO
 

 13. 

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

Transmitter and receiver specs do not reflect bandwidth penalties incurred by the length of the optical fiber and its bandwidth performance. 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.
 

 14. 

Using the information supplied above, assuming the component specifications are per TIA standards, calculate the cable plant loss budget for the 50m link, including the loss of the patchcords.
a.
1.68 dB
b.
1.35 dB
c.
2.77 dB
d.
3.18
 

 15. 

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.
1.68
b.
1.35
c.
2.77
d.
3.1’, ]8
 

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

 16. 

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
 

 17. 

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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