Cisco 200-355 Online Practice Questions and Exam Preparation

Cisco 200-355 Online Questions & Answers

• Question 381:

  Which calculation computes the EIRP of an antenna?

  A. EIRP = Tx power (dBm) + Antenna Gain (dBi) - Cable Loss (dB)
  B. EIRP= Cable Loss (dB)+ Antenna Gain (dBi) - Tx power (dBm)
  C. EIRP = Cable Loss (dB)+ Antenna Gain (dBi) / Tx power (dBm)
  D. EIRP = Tx power (dBm) + Antenna Gain (dBi) / Cable Loss (dB)
  E. EIRP = Antenna Gain (dBi) - Cable Loss (dB) * Tx power (dBm)
  F. EIRP = Tx power (dBm) * Antenna Gain (dBi) / Cable Loss (dB)
  A. EIRP = Tx power (dBm) + Antenna Gain (dBi) - Cable Loss (dB)

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  EIRP (Effective Isotropic Radiated Power)

  EIRP (Effective Isotropic Radiated Power) is the actual amount of signal leaving the antenna and is a value measured in db and is based on 3 values:

  1.

  Transmit Power (dBm)

  2.

  Cable Loss (dB)

  3.

  Antenna Gain (dBi)

  The dB measures the power of a signal as a function of its ratio to another standardized value. The abbreviation dB is often combined with other abbreviations in order to represent the values that are compared. Here are two examples:

  dBm --The dB value is compared to 1 mW.

  dBw --The dB value is compared to 1 W.

  You can calculate the power in dBs from this formula:

  Power (in dB) = 10 * log10 (Signal/Reference)

  This list defines the terms in the formula:

  log10 is logarithm base 10.

  Signal is the power of the signal (for example, 50 mW). Reference is the reference power (for example, 1 mW).

  How to find EIRP

  To determine EIRP follow this equation:

  -Cable Loss + Antenna Gain = EIRP

  https://supportforums.cisco.com/document/49506/snr-rssi-eirp-and-free-space-path-loss

• Question 382:

  A company wants to implement wireless in all 20 remote office locations and wants centralized management of these remote sites. What application would meet the requirements?

  A. Cisco autonomous access points in FlexConnect mode
  B. Cisco point- to multi-point wireless bridging
  C. Split MAC architecture utilizing CAPWAP and WLC
  D. Control and Provisioning of Wireless Access Points
  C. Split MAC architecture utilizing CAPWAP and WLC

• Question 383:

  Which RRM feature allows an access point to avoid non-IEEE 802.11 interference?

  A. DCA
  B. TPC
  C. RFgroups
  D. coverage hole detection
  A. DCA

• Question 384:

  A client is upgrading its wireless infrastructure to IEEE 802.11n-capable access points. Which technology leverages the 802.11n radios to provide better coverage and throughput for legacy IEEE 802.11a/g clients?

  A. spatial streams
  B. MRC
  C. MIMO
  D. beam-forming
  C. MIMO

• Question 385:

  An access point is currently transmitting at 4 mW. The customer needs to increase its signal strength by 6 dB to create a larger wireless cell. What should the new transmit power be?

  A. 8 mW
  B. 10 mW
  C. 12 mW
  D. 16 mW
  E. 24 mW
  D. 16 mW

• Question 386:

  What are the interface statuses of a lightweight AP working in rogue-detection mode?

  A. radios turned off, Ethernet interface up
  B. radios and Ethernet interfaces up
  C. radios turned on, Ethernet interface shut down
  D. radios turned on, Ethernet interface status controlled by Cisco WLC
  A. radios turned off, Ethernet interface up

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  In this mode, the AP radio is turned off, and the AP listens to wired traffic only. The controller passes the APs configured as rogue detectors as well as lists of suspected rogue clients and AP MAC addresses. The rogue detector listens for ARP packets only, and can be connected to all broadcast domains through a trunk link if desired.

  http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/70987-rogue-detect.html

• Question 387:

  The Cisco WCS administrator wants to create an accurate RF heat map based on RF prediction data. Which statement about map creation in Cisco WCS is true?

  A. The administrator must manually add walls, doors, and windows to the map.
  B. Cisco WCS automatically detects walls, doors, and windows and adds them to the map, but only when Cisco WCS Navigator is available.
  C. Cisco WCS automatically detects walls, doors, and windows and adds them to the map, but only when a Cisco 3300 Series MSE is available.
  D. All walls, doors, and windows must be included in the file that is uploaded as a background map.
  A. The administrator must manually add walls, doors, and windows to the map.

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  General Notes and Guidelines for Using the Map Editor Consider the following when modifying a building or floor map using the map editor.

  Cisco recommends that you use the map editor to draw walls and other obstacles rather than importing an .FPE file from the legacy floor plan editor.

  If necessary, you can still import .FPE files. To do so, navigate to the desired floor area, choose box, and browse to and choose the .FPE file.

  You can add any number of walls to a floor plan with the map editor; however, the processing power and memory of a client workstation may limit the refresh and rendering aspects of WCS.

  Cisco recommends a practical limit of 400 walls per floor for machines with 1-GB RAM or less.

  All walls are used by WCS when generating RF coverage heatmaps.

  However, the MSEs use no more than 50 heavy walls in its calculations, and the MSE does not

  use light walls in its calculations because those attenuations are already accounted for during the calibration process.

  If you have a high resolution image (near 12 megapixels), you may need to scale down the image resolution with an image editing software prior to using map editor. http://www.cisco.com/c/en/us/td/docs/wireless/wcs/7-0/configuration/guide/WCS70cg/7_0maps.html

• Question 388:

  Which statement best describes the ability of a wireless client to access and transmit a data frame to an AP?

  A. The client listens to the media until polled by the AP using PCF to send its data.
  B. The client listens to the media until a data frame is finished, at which time it transmits, unless a collision of data frames has occurred.
  C. The client uses random countdown timers to start the transmission of a data frame.
  D. The client listens to the media and countdown timers to start the transmission of a data frame.
  D. The client listens to the media and countdown timers to start the transmission of a data frame.

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  http://www.ciscopress.com/articles/article.asp?p=1271797andseqNum=2

• Question 389:

  What are three characteristics of the 802.11g standard? (Choose three.)

  A. speed of as much as 11 Mb/s
  B. speed of as much as 54 Mb/s
  C. bacward-compatibility with 802.11a
  D. backward-compatibility with 802.11b
  E. OFDM as an additional modulation technique
  F. OFDM and CCK as additional modulation techniques
  B. speed of as much as 54 Mb/s
  D. backward-compatibility with 802.11b
  E. OFDM as an additional modulation technique

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  802.11g is the third modulation standard for wireless LANs. It works in the 2.4 GHz band (like 802.11b) but operates at a maximum raw data rate of 54 Mbit/s. Using the CSMA/CA transmission scheme, 31.4 Mbit/s is the maximum net throughput possible for packets of 1500 bytes in size and a 54 Mbit/s wireless rate (identical to 802.11a core, except for some additional legacy overhead for backward compatibility). In practice, access points may not have an ideal implementation and may therefore not be able to achieve even 31.4 Mbit/s throughput with 1500 byte packets. 1500 bytes is the usual limit for packets on the Internet and therefore a relevant size to benchmark against. Smaller packets give even lower theoretical throughput, down to 3 Mbit/s using 54 Mbit/s rate and 64 byte packets. Also, the available throughput is shared between all stations transmitting, including the AP so both downstream and upstream traffic is limited to a shared total of 31.4 Mbit/s using 1500 byte packets and 54 Mbit/s rate. 802.11g hardware is fully backwards compatible with 802.11b hardware. Details of making b and g work well together occupied much of the lingering technical process. In an 802.11g network, however, the presence of a legacy 802.11b participant will significantly reduce the speed of the overall 802.11g network. Some 802.11g routers employ a back-compatible mode for 802.11b clients called 54g LRS (Limited Rate Support). [2] The modulation scheme used in 802.11g is orthogonal frequency-division multiplexing (OFDM) copied from 802.11a with data rates of 6, 9, 12, 18, 24, 36, 48, and 54 Mbit/s, and reverts to CCK (like the 802.11b standard) for 5.5 and 11 Mbit/s and DBPSK/DQPSK+DSSS for 1 and 2 Mbit/s. Even though 802.11g operates in the same frequency band as 802.11b, it can achieve higher data rates because of its heritage to 802.11a.

  http://en.wikipedia.org/wiki/IEEE_802.11g-2003

• Question 390:

  What increases bandwidth and resists multipath problems by carrying data in subcarriers?

  A. Direct Sequence Spread Spectrum
  B. Frequency Hopping Spread Spectrum
  C. Narrow Band Frequency
  D. Orthogonal Frequency Division Multiplexing
  D. Orthogonal Frequency Division Multiplexing