MIS505 Final Exam

How do wireless LANs operate in terms of signal transmission?

-They are OSI dominate: data link & physical layer.
-Use single networks (using physical & DLL standards)
-Uses radio signals for physical layer transmission on customer premises.

What is an access point? Explain in detail.

-Access points connect hosts directly.
-They forward frames between hosts.

-Connects wireless access points to servers and internet access routers on ethernet.

Dead zones

-where signals are blocked of a direct path between a sender & receiver

-This can be due to a thick walls or objects. This can become worse when frequency increases because radio waves become less able to bend around objects.

Multipath interference

is the most serious problem with propagation at WLAN frequencies

electromagnetic interference

-devices that interfere with WLAN because they produce
-electromagnetic radiation that is used in data communications such as wireless phones, microwaves, and nearby access points

Inverse square law attenuation

-very rapid attenuation
-signals spread out and become weaker at each point on the sphere as the sphere expands

Absorptive attenuation

-signals are lost due through energy absorption
-radio signals can be absorbed air molecules, plants, and water.
-in optical fiber, attenuation is due to the absorption of signal strength as signal propagates

Service bands

Ranges that are dedicated to a specific purpose, like FM radio, emergency response, GPS, etc.
They are divided into channels as signals sent through different channels do not interfere with each other

Frequency spectrum

all possible ranges from 0Hz to infinity

Explain 2.5 GHz

-Unlicensed service band
-small total bandwidth
-there can only be three non-overlapping 20 MHz channels
-it is difficult to put by access points because it will cause channel interference

Signal bandwidth

-subtract the lowest frequency from the highest frequency
-the range is between the highest & lowest frequencies
-as transmission speed increases, the signal bandwidth also increases

channel bandwidth

-have a wide channel bandwidth and therefore high speed

Explain 802.11i in high detail.

-Environment:This is used for personal homes, residencies.
-Authentication basis: It does not use 802.11x authentication as this would be overkill.
-Technical security: It can be technologically strong, but weak security can compromise the technological security.
-Operational threat: mismanage pre-shared key (giving it to an unauthorized person, not changing it, or having a weak passphrase)

Explain 802.11X in high detail.

-Environment: this is on the enterprise mode level, it used for big companies who have multiple access points.
-Authentication basis: it is credentialed by using the 802.11x authentication server
-Technical security: it is extremely technologically strong, same ongoing message protection with message-by-message confidentiality, integrity, and authentication.
-Operational threat: rogue access points, and evil twin access points

Explain 802.11ax (WIFI 6) in detail.

addresses a problem different from speed, but rather density, it promised it will serve 4 times as many hosts per access points as 802.11ac

Ip Routing

-Routers are organizes as meshes. Gives more reliability because it allows many possible alternative routes between end points.
-However for meshes, there are multiple ways of sending packets
back to reach its destination.

NAT (Network Address Translation)

-Allowing people outside a corporation to learn their internal IP address is a security risk. To prevent this, corporations use NAT. Where they use external IP addresses instead of their internal IP addresses.

-Security reason: external hackers can use sniffers, sniffers can learn IP addresses, attackers then will attack these IP addresses, with using NAT attackers will only know the external IP addresses and not the internal Ip address. Therefore, Private IP address can only be used inside firms.