Wireless engineer interview questions

A recruiter from Atlanta submitted this set of questions for interviewing at a wireless equipment company.

  1. Describe your home WLAN setup.(Pay attention to candidate’s confidence. Plus if the candidate built it himself. Plus if the network is secured additionally, regardless of the protocols used. Plus if the candidate fought poor coverage.)
  2. Ad-hoc vs. infrastructure topology. Advantages and disadvantages. Ad-hoc networks are easy to set up. By definition ad-hoc WLANs do not require access point, so they are cheaper. With infrastructured WLANs one can connect to wired LAN, enable wireless roaming for office workers, centralize WLAN management, boost the range.
  3. Your preferred brand for wireless cards and access points. (An experienced candidate will be able to come up with strong argument to defend his preferences. He will point to the past projects as well.)
  4. Range and throughput of 802.11a, 802.11b and 802.11g networks. The official spec for 802.11a is 54 Mbps and 25-75 feet indoors. The official spec for 802.11b is 11 Mbps and 100-150 feet indoors. The official spec for 802.11g is 54 Mbps and 100-150 feet indoors. An experienced candidate will provide his own observations.
  5. How do you secure a wireless network? Forbid SSID broadcasting, enable MAC-level access where appropriate, enable WEP, enable 802.11i where available, enable firewalls, enable WPA.
  6. What does Wi-Fi stand for? Wireless Fidelity.
  7. What is 802.11i? It’s a new IEEE standard defining wireless network security.
  8. What are the recommended channels if you’re setting up three WLANs and want minimum interference? 1, 6 and 11 for the US, 1, 7 and 13 for Europe and 1, 7 and 14 for Japan.
  9. What are your preferred tools for wardriving? Somewhere the names Kismet, *stumbler or others should come up. Ask the
    candidate to describe his preferred configuration for wardriving.
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6 Comments on Wireless engineer interview questions

  1. Abhishek Jain
    Posted 6/17/2005 at 4:07 am | Permalink

    Please publish Sample/Interview/Test Questions for SS7 Protocol Stack.

    -Abhishek Jain

  2. Thirumurugan
    Posted 2/28/2007 at 7:03 am | Permalink

    Standared Wireless Protocol?

    what is the difference in 802.11b and 802.11g? and what typw frequency used?

    Expalin Basic Wireless Security’s?

    What is meatn by UUNI? & Frequency range?

  3. Sean Muir
    Posted 9/25/2007 at 7:23 am | Permalink

    Thirumurugan said,

    Standared Wireless Protocol?

    what is the difference in 802.11b and 802.11g? and what typw frequency used?

    Expalin Basic Wireless Security’s?

    What is meatn by UUNI? & Frequency range?


    802.11b uses 2.4GHz as does 802.11g. The difference between them is the way in which the data is encoded onto the carrier:

    802.11b uses DSSS (Direct Sequence Spread Spectrum) which has loads off issues, mainly bandwidth and multi-path.

    802.11g uses OFDM (Orthogonal Frequency Divisional Multiplex) for higher modular rates from BPSK up-to 64QAM. However it also uses CCK (Complementary Code Keying) this is for backward compatibility with 802.11b.

    However 802.11b/g are restricted to having only 3 clear channels that don’t overlap; which from a scalable point off view is bad when it comes to internal WLAN, unless using single cell technology.

  4. Bear
    Posted 9/8/2008 at 12:47 am | Permalink

    Well, what kind of accesss mechanism is used by IEEE 802.11? Answer: CSMA/CA, or more specificly, DCF.

  5. Rohit Jha
    Posted 2/6/2009 at 9:40 am | Permalink

    6)The name of a popular wireless networking technology that uses radio waves to provide wireless high-speed Internet and network connections. The Wi-Fi Alliance, the organization that owns the Wi-Fi (registered trademark) term specifically defines Wi-Fi as any “wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers’ (IEEE) 802.11 standards.”

  6. Rohit Jha
    Posted 2/6/2009 at 9:42 am | Permalink

    SOme Step to Secure
    1)Secure your wireless router or access point administration interface

    2) Don’t broadcast your SSID

    3)Enable WPA encryption instead of WEP
    4) Use MAC filtering for access control
    5) Reduce your WLAN transmitter power
    6) Disable remote administration

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