BeITCertified Cisco Free Download Actual 642-321 exam questions dumps as PDF by humsub


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									Exam Name:      Cisco Optical SDH Exam
Exam Type:      Cisco
Exam Code:      642-321                                           Total Questions:    59

Question: 1
For lasers with tightly controlled wavelengths, approximately how far apart are the centers of
adjacent wavelengths when 100 GHz spacing is used in a DWDM system?

A. 0.4 nanometers
B. 0.6 nanometers
C. 0.8 nanometers
D. 1.2 nanometers
E. 1.6 nanometers

Answer: C

Question: 2
The dispersion of a non-zero dispersion shifted fiber is 6 ps/nm*km at 1550 nm and 10 ps/nm*km
at 1610 nm. What is the minimum dispersion compensation required if an L-Band DWDM signal
travels through 200 km of fiber and has a dispersion of 1800 ps/nm?

A. None
B. -600 ps/nm
C. -200 ps/nm
D. +600 ps/nm

E. +600 ps/nm

Answer: C                                      d
Question: 3

Which type of multiplexer is shown in the exhibit?

A. Thin film filter
B. Fiber Bragg Grating
C. Arrayed Wave Guide
D. Erbium fiber amplifier

Answer: C

Question: 4
In the OSNR model for EDFA amplifier, SNRout = 1/(1(SNRIN + FhvB/PIN), what does the
SNRIN represent?

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Exam Name:      Cisco Optical SDH Exam
Exam Type:      Cisco
Exam Code:      642-321                                              Total Questions:     59

A. The signal to noise of the current optical amplifier.
B. The signal to noise of the previous amplifier of source.
C. The signal to noise introduced by the optical amplifier.
D. The accumulated noise to signal ratio of the optical channel.

Answer: B

Question: 5
How is a Thin filter fabricated?

A. The glass core is doped with an Erbium in periodic segments of the fiber.
B. Layers of high index and low index material are deposited on a glass substrate.
C. Thin layers of silica glass are place onto wafers to produce a prism-like effect.
D. Fiber is etched with an ultraviolet laser that is precisely spaced for specific wavelength filtering.

Answer: B

Question: 6
What are three factors that limit the maximum distance of an amplified optical signal without
regeneration? Select three

A. Fiber dispersion
B. Signal attenuation
C. Transmitter power
D. Amplifier bandwidth
E. Receiver dispersion tolerance

Answer: A, B, E

Question: 7

When designing a DWDM system with multiple amplified spans, a pre-amp is needed Site B to
______(Choose three)

A. Offset the OADM loss at site B.
B. Overcome the high multiplexer loss at Site A.
C. Amplify signal levels after the high loss through Fiber Span 1.
D. Adjust add channels at Site B to be at the same level as the pass through channels.

Page 2 of 21
Exam Name:     Cisco Optical SDH Exam
Exam Type:     Cisco
Exam Code:     642-321                                           Total Questions:   59

E. Ensure that the per channel power is higher than the minimum needed for the post-amp at Site

Answer: A, C, E

Question: 8
If the dispersion of a given fiber is 17ps/nm*km at 1550 nm and zero at 1310 nm, then what is the
accumulated dispersion of an ITU wavelength after it travels 200 km?

A. 0 ps/nm
B. 200 ps/nm
C. 340 ps/nm
D. 3400 ps/nm
E. More information is needed

Answer: D

Question: 9
The ONS 15216 is a 32-channel system. The ONS 15216 OADMs are capable of adding and
dropping one, two, or four channels. How are the OADMs provisioned to add and drop specific

A. The ONS 15216 OADM can be provisioned to add/drop one two, or four channels via Cisco
   Transport Manager (CTM).                   d
B. The ONS 15216 OADM consists only of a four-channel module, and the number of ports
   utilized determines whether it is a one, two, or four channel OADM.
C. Three separate OADM modules are available for one, two, and four channels. The wave

   lengths to be dropped and added are programmable via Cisco Transport Manager (CTM).
D. The ONS 15216 OADM consists only of a four-channel modul. Two-channel and four-channel

   support is available by stacking the single-channel module.
E. The ONS 15216 OADM is available in one, two, four channels. There are 32 single- channel
   OADM modules, 16 two-channel OADM modules, and 8 four-channel OADM modules.

Answer: E

Question: 10

Page 3 of 21
Exam Name:     Cisco Optical SDH Exam
Exam Type:     Cisco
Exam Code:     642-321                                            Total Questions:   59

                                                d      .c
The exhibit shows a 15454/15216 DWDM system and alarm indications. What are two possible
sources of trouble shown in the system? (Choose two.)

A. Fiber failure between Sites A and D.
B. EDFA failure at Site A (clockwise direction)
C. EDFA failure at Site C (clockwise direction)

D. 15216 multiplexer at Site A (counter-clockwise direction)
E. OADM pass-through (West “OUT”) failure at Site (Clockwise)

F. Wavelengths 1 and 3 transmitter failures at Site A (clockwise direction)

Answer: B, F

Question: 11
What are two important considerations when using 2- or 4-channel 15216 OADMs? (Choose two)

A. All “Add” channels require uniform power levels.
B. The flexibility of wavelengths per OADM is limited.
C. It is easier to balance “Pass-Through” and “Add” channels.
D. There is lower pass-through loss using multi-channel OADM.s
E. You can extract a single channel without dropping other channels.

Answer: A, B

Question: 12
A 2.5 Gb/s (OC-48 or STM-16) optical signal with a dispersion tolerance of 1200 ps/nm goes
through fiber with 18ps/nm*km of dispersion. How many 15216-DCU-350 equivalents are needed
for enough compensation after traveling 100 km?

A. 0

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